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Any time you want to talk tapers, I'm your man.  I believe that the taper is the soul of the rod, the rest just window dressing (and while I strive to dress my rods as functionally as possible, and as aesthetically, I agree that it seems like some folks do get their priorities backwards focusing more on the wrappings, tipping, engraving, etc., than on a good action to start with).

I do quite a bit of "prototyping," building multiple tips with different actions for rods, to get a practical idea of what changing a taper, or designing one from scratch, really does.

I also have dozens of graphs of rod dimensions (which for the past few years I've found more helpful than stress curves) to help me compare tapers to actions (though charts are only useful if you've cast the rod, so you know what it does).

I do really appreciate ALL the discussion topics, from thread to glues to varnishes to gizmos, but I do agree that tapers sometimes get lost (though it is hard to convey what a rod feels like without letting someone else cast it, and God knows rodmakers are an opinionated bunch who don't often agree on what each prefers in rod action).  (Chris Obuchowski)

I was wondering ... How many customers actually are educated in tapers that buy cane rods??? I don't sell rods to cane fly fisherman, my rods go to family and friends that have never fished a cane rod while I learn to become more adept at building. I've always wanted to know more about the cane rod buying community. I know there's a faction that buys just for esthetics, but how many really are educated buyers???  (Bill Tagye)

I feel pretty comfortable in saying that somewhere around 20-25% of the folks who buy rods know their tapers pretty well.  This summer I had a customer who wanted a rod "sorta like a Perfectionist, but a little stiffer in the butt."  I had another customer last year who wanted a Payne 200L just like the one his dad fished.  Another one wanted a 6' 4 weight with  a stiff butt that would still handle 6x tippets and short casts.  I have a regular customer in Germany who really knows his stuff, and gets quite specific about the taper design in the rods I build for him.

On the other hand, I've had plenty of customers who ask things like "I fish a Scott glass rod, and really like it.  Can you build a bamboo rod like that?"  Or, "I'm new to fly fishing and want the best of everything.  I hear cane rods are the best.  What would you recommend?"  (Harry Boyd)

Therein lies the confusion. "You" take a person liking a stiff butt or a 200l for knowledge about tapers, I was trying to relate this to a stress function. something more measurable in result than a feel, although I agree that is the final test.

Don't take this all wrong, I'm not saying that the old rods or contemporary copies are not great rods, They simply don't tell you how they were engineered with out another tool

I handed a rod that I built as a slingshot taper to a guy who is a very good caster, and his comment was, this is really a fast rod.

So the test I am seeking is what was your design criteria and how do you know when it matches something you can measure. and is it modifiable without the add a few thousandths here or there. I accept the fact that R.N. and a few others can design a rod by feel, but can the skill be transferred.  (Jerry Foster)

Perhaps I should have distinguished between  knowledgeable and ignorant rod buying customers.  Ignorant, but able-to-be-educated, I can live with. I guess I lean more towards the touchy-feely than the empirical.  I haven't really thought a lot about relating how a rod feels to a stress value expressed in numbers.

One "number" that helps me visualize "feel" is a slope value of the rod taper.  Ray Gould describes the slope values well in his latest book, so I won't go into it in detail here.  The higher the slope of the taper, the stiffer the rod feels.  I think that's somewhat similar to the Powell ideas Chris Obuchowski described.

In my opinion, Garrison's math is a good guide for comparing tapers, and for making relatively minor changes to those tapers.  Enough rebuttals of his theories have been written to convince me that Garrison's math is really of quite limited usefulness beyond making comparisons and small changes; Milward, for example.  Don't get me wrong... I use Frank Stetzer's Online Hexrod and find it a great tool.  I greatly appreciate Frank putting it online and Wayne laying out the concepts.  But I think stresses as expressed by Garrison are quite limited as a design tool.  As a comparison tool, they somehow work.  Engineers almost universally agree that static stresses on a cantilevered beam are not an adequate model for describing how fly rods bend and straighten under increasing and decreasing loads.

You ask if the skill of designing tapers by feel can be transferred.  I don't know that it can be transferred, but I think it can be learned with practice and experience.  That's what I sought to express in urging us all to become better casters.  (Harry Boyd)

I have been trying to get my hands on Milward's book.

Perhaps someone can enlighten me as to the key principal in his work that is an overwhelming principal of design that makes his disciples discredit the results of beam deflection. (RK?)

Yes, Ray's targets for rate of change are valid also, just haven't had time to see how they fit into stress evaluation.

I had many talks with Press Powell (before his passing) about rod design and he was very firm that EC's formulas were the only rod design tools one needs.

So are we stuck here?   (Jerry Foster)

I read Milward's book, too.  To my experiment via my simulator, stress curve varies accordingly when a rod is flexed.  Stress point (high stress point) will move to mid of the rod and finally toward grip side.  Everybody knows about this in actual fishing situation.

Garrison's math does not move rod, of-course, and it focuses to one fixed situation, movement of the rod is fixed to the  state of 4 x  gravity (acceleration) situation (this is the translated rod of Don Phillips book), it does not assume the rod will be bent (within his math) since 5 inches interval are always 5 inches.

It is obvious that a flexed rod has different shape of stress curves from time to time.

But when we try to calculate desired dimension from such stress curves, cause and effect relationship will always result in the same dimension number. Flexed stress curve will also produce the same dimension numbers to the one from unflexed stress curve, since math will change to the effect.  Even MOE, change of angles are taken in account...

So, it is okay if we use Garrison's math to calculate dimension number from stress curve.  I confirmed this point by  calculating dimensions from fully bent stress curve.  The resulted dimension is same.  My program can calculate dimensions from rod flexure. Try to think like this, one rod can show  various stress curves, but it is the same rod.

It is not okay to try to draw a flex curve of a rod from Garrison's moment or stress curve. When a rod bend, moment calculation should  change the length of interval which is caused by bend.  To draw a deflection curve, we may need to consider the effects of gravity itself either as well as inertia of rod movement.  (Max Satoh)

My understanding of Max's post is that if you consider a fly rod as a lever with a line at the end along with its own distributed mass being accelerated, the more acceleration in the forward stroke the more bend in the rod- with bending increasing from tip to butt. However the degree bending changes the effective length of the lever (the more bend the shorter it gets). How acceleration changes effective length is a function of the rod taper. Steep tapers will bend mostly at the tip and remain long levers under large accelerations. Shallower tapers will shorten more under lighter loads.

So Max says that there is a family of bend forms created from a single rod taper under different accelerations. In terms of stress the highest stress will be in the part of the rod which is under load and bending. Once a portion of the rod straightens out and is in line with the fly line the bending stress goes toward zero. Milward did an experiment in which he measured the degree of bending at 5" stations along a rod at he maximum acceleration casting load by using high speed photography. He then used the standard formula to relate f(b) to the observed bend using the standard formula. He compares his stress  curve to the Garrison curve. They are, in fact very different. The major difference can be accounted for by the bending of the rod and the resultant shortening. This is I believe what Max means by saying the same rod can have different stress curves. Each bend form generated from a single taper will have a different stress curve. The tricky part is that the load and dimensions predict the bend forms however the stress curves for different bend forms of the same rod do not predict the same dimensions. This is because large parts of the rod tip are left out of the stress curve at large bending levels. This, I think, is why Garrison didn't let his rods bend.

I hope this is not a total distortion of your post Max.  (Doug Easton)

Thank you, thank you,  you did pick up what I wanted to say very much.  Thus,  a cooperation would have a good result.

The tricky part is that the load and dimensions predict the bend forms however the stress curves for different bend forms of the same rod do not predict the same dimensions.  This is because large parts of the rod tip are left out of the stress curve at large bending levels. This , I think, is why Garrison didn't let his rods bend.

I rather think a little romantic about this.

My calculation is like this;

add moment, calculate the bend, on time 1:

add moment, calculate the bend, on time 2:

Thus, moment value for time x becomes less and less on tip top. Finally the tip top part would have zero moment which means straightened by some force, by fish, line cast or tree.

Then you questioned why the straightened tip top could be reverse calculated to dimension? I say yes, we can get the same dimension if we get a set of cause-effect pairs of moment, bend, (as well as MOE, weight). Even if the tip is straighten out, the calculation algorithm include the length from tip top to butt end (I mean action length). Doing reverse calculation from butt side to tip side, subtraction effect will remain tip dimensions from 1 inch to another.

About the reason why Garrison didn't let his rod bend?:

* He did not have PC like now.

* By assuming  the rod length to no bend, he could get higher stress value at tip top part oppositely. (since this is mere a division operation, M/Z, fixing M would result in more value then varying M according to bend)

* He possibly would like to make such a design formula by using the height of the stress value which would represent a nature of rod bend. So the slope of the curve from left to right would imply progressive nature of bend, or flat slope  for entire bending, and parabolic, etc..

* That is Stress Curve of Garrison.

* But actual world,  Tip top (around 0-15 pt) does not have such high stress, then people start confusing...

Most people start calculating moment from tip top toward butt side, even if bending is taken into account. It will cause higher tip top moment since he is calculating straight  rod at the beginning.  Calculation from butt to tip considering bend, will result lower moment value on tip top.  These stress curve would not have high stress on the tip top.  (Max Satoh)

Just to stir the pot:

One "number" that helps me visualize "feel" is a slope value of the rod taper.  Ray Gould describes the slope values well in his latest book, so I won't go into it in detail here.  The higher the slope of the taper, the stiffer the rod feels.  I think that's somewhat similar to the Powell ideas Chris Obuchowski described.

And beyond that, the higher the slope IN STATIONS OF A TAPER make the rod a better distance, or roll, or close in rod.

Compare stress curves to slopes.   Look for the places where a rods slope increased or decreases.  

I compare my tapers to an average slope and have noticed that the taper usually has a "wiggle" around the ferrule.  flatter going in and steeper coming out. 

Anyone else see this in their tapers?   If so, why?  If not, why not?  (Terry Kirkpatrick)

The wiggle is the result of the diameter being bumped at the ferrule. A good representation of this in a slope can be found in the Fierabend article in The Wise Fisherman's Encyclopedia. Reed has the extract on his site.

First page.

Second page.  (Larry Blan)

Gould’s slope value idea is just a way of getting a quick idea of how fast the taper is, it is a bit misleading on some parabolics, as they have slower butt tapers than tip tapers.

I don't know why there is a wiggle at the ferrule, and I cannot think of a good reason.  (Robin Haywood)

Ah, now the question about the wiggle in the middle. I am assuming you mean the flattening of the taper at the ferrule location on my double parabolics. This is done for a specific purpose and that is that I believe that putting a nickel silver ferrule in the middle of a 2 section rod installs a stiff strong connector that will not bend at the same rate the cane does. Thus flattening the taper there offsets that difference and provides a smoother action to the cast.  (Ray Gould)

I didn't know what was meant by the wiggle, I imagined it as some kind of bulge at the time, which was probably stupid of me.

I quite liked the look of your double parabolics, but have not had the time to properly analyze them, there was something about them that concerned me but I can't find the graphs to look at to see what it was. It wasn't much though, in fact I remember thinking that the purists would probably not accept them as parabolics!  Was it that they have convex but tapers and I tend to like them concave? If it was not so late I'd go and find out, so advance apologies if I'm talking gibberish.  I certainly would not have worried about the flattening of the area around the ferrule since I like rods with the top third and the bottom half of a quicker taper and a slower bit in the middle, this is a bit of a reduction ad absurdam, but you can probably see what I mean.

Entirely off subject I like coil springs on cars that shape too, but whenever I have spoken to a suspension expert they go on about the difficulties of designing and making variable rate dampers. This is curious since a chum and I designed a perfectly viable design for one over 20 years ago which was tested and worked and now we have electronics and fluids which are electronically variable in viscosity. Since neither of us wish to emulate Tucker or, for that matter Citroen, in terms of grief per pound earned, we gave up with big sigh and shaking of heads! He was interested since he is by training an oil chemist of fairly exotic kind but I have recently learned that an ex-colleague is involved in electronic damper design, so, thirty years too late there may yet be hope!

Back on track I will say that I do not and never have liked step down ferrules for this reason.  I've never used them intentionally, even when there was no choice I built up the butt section to take the larger diameter female. In fact, I tend to build up both sections, even now, because I still have the heeby-jeebies about removing cane! But not always, I'm mellowing a bit with age, depends on the rod and sadly, what ferrules I have to hand, but don't tell anyone.  (Robin Haywood)

I don't believe most buyers have any knowledge of stress curves, nor should they. They buy rods for a lot of reasons, cosmetics, action, collectibility of the maker, etc. But the stress curve is in the dimensions, whether they know it or not.

Since it's raining here lets give a discussion about stress curves a start.  Although I'm not  the most qualified to do this..

1. Is there an overall agreement that Garrison had the optimum stress values for bamboo correct.  140k to 220k in oz's

I see a lot of rods that break this basic tenant and are beloved by their makers.

2. Every rod is built to optimize it's casting ability at one specific length of line.

A stress curve for 4 wt at 40' reflects the weight of the line beyond the tip

3. Wayne’s topic.. the stress curve reflects the character of the rod.

A parabolic is easy to see, the others (fast, slow, etc.) we will have to work on.

This should be a basic start.

Comments and next steps to understanding.  (Jerry Foster)

I think almost no one who has not made bamboo rods (and probably plenty who have but didn't read Garrison or Cattanach) are not familiar with stress curves.

1. I don't have a mechanical engineering background, so I don't know of any data from destructive testing regarding the "idea stress values" of bamboo.  My guess is that no formal destructive testing has been done with bamboo as a building material to provide empirically based numbers.  I don't recall how Garrison arrived at his numbers (I'll have to go back to the "Bible" tonight and see what I can learn).

I agree that there are a number of rods out there that violate these "rules", some that have been in use for decades without failure.

Having built a couple of Garrison tapers, I can say I like the smooth action, but they do seem to be slightly overbuilt (on the other hand, you can throw anything from small dries to huge heavily weighted stone flies, with split shot, and big strike indicators, with a rod like a 209e, a 5 wt, so maybe they really aren't "overbuilt" if your fishing swings from one extreme to another.  I probably wouldn't fish size #24 flies with 7 or 8x tippets though, at least not if I don't want to break off most of the fish).

As an all around fishing tool, covering the largest gamut of situations, I do think that Garrison rods are excellent.

2.  I agree with number 2.

3.  I agree that stress curves reflect the character of the rod. . .but I think you need to look at the actual dimensions to get an idea of line wt, and whether the rod will be strong, soft, etc. . .how it might perform in actual fishing situations.

For those interested in rod action, Ed Hartzell a number of years ago wrote a very concise little explanation of Powell rod actions (using the A, B, C system devised by EC Powell, and as described in several monographs and publications put out by the Powell rod company long ago),  that provide an excellent starting point, and common vocabulary, for discussing basic rod actions, and variations from them.  Oh, Ed's article was published in The Planing Form.  (Chris Obuchowski)

1. I agree with the general range of Garrison's optimum stress values, not to the extend that it is important that it defines a breaking point, but rather that it helps to gage at which stresses a rod is optimized during design.  For a set line weight/length, a rod that shows an average (lets call it 'average' though it isn't really) stress of 140k will be underlined.  There isn't enough line mass to load or flex the rod properly.  Conversely, one who's average is 220k will be overlined.

There is a magic spot, for me at least, around 180k that will allow me to define a rods proper line weight for progressive rods.  Look at the Garrison 209 in RodDNA for example.  Setting the line weight at 5 and the line cast at 45, I see an 'average' stress of around 165k or so.  To me this says that with up to 45' of line out the 209 is going to feel slightly underlined as I've found my optimum stress for accurately generating a progressive taper (using this line length for this rod weight) is around 180k.  As such, if I were to design a rod for a 5 wt line with a progressive action using the 209 as a template, I would lighten up the stresses until they neared that target.  I have empirically found this to be accurate for my personal fishing and casting preferences.

With tip action and parabolic rods the target of 180k moves around a bit, and is more difficult to pin down due to the nature of the graph, but again by doing some empirical testing I know wherein that optimum stress lies for each line weight and curve style.

This is just a little bit skewed as I don't use RodDNA nor Hexrod when designing a taper.  I have a heavily modified version of Paul Griffin's Excel spreadsheet (thank you Paul!) that I have setup to, among other things, view stress curves in a 3 dimensional format, with the X axis and Y axis being the standard values and the Z axis set as the amount of line cast from 2'-48' (variable of course).  Using this standard I can easily see the stresses, and rate of change of those stresses, under various line lengths for each taper.  And they look mighty cool! ;)

2. I think that a finished rod is made to optimize a certain range of line cast, or a few specific ranges in the case of rods with hinges etc., but not for one specific line length.  However, when a taper is being designed it is important to use a standard so that you are comparing apples to apples.  If you are using stress curves to design a 4wt, you don't want to use 40' of line cast for one taper and 50' for another, so in that sense you do need to use one line length to optimize the consistency when designing and comparing.

3. Thinking of stress curves as a tool that reflects the character of the rod is a perfect way to look at it.  Parabolic, progressive and tip action are all easy to see by the shape of the curve, and the overall stiffness (preferred line weight) is easy to see by the stresses exhibited.

The term action, and its overly simplified descriptions, will always give problems, especially when you're talking with a graphite convert or someone who isn't too familiar with cane.  I'm always careful to speak in terms of 'tip action', 'even or full flexing', 'flexible or soft butt section' and the like in such circumstances and not 'fast', 'medium' or 'slow'.  Way too many folks equate 'fast action' with 'stiff', 'slow' with 'soft' etc.

Some of this is akin, I suppose, to Powell's descriptions of A, B and C actions as Chris O. mentions.  As an aside, the original pamphlet can be read on Banjo's web site.   (Chris Carlin)

OK let's try this..

A customer comes to you and says " I'd like to buy a 3 wt rod that will punch 40' of line and drop a fly on the water without a ripple."

Where would you start?  (Jerry Foster)

A lighter line version of the 7 1/2 foot three piece 4 wt. Hardy Marvel? (David Zincavage)

I'm gonna assume it's for small dries and nymphs, small stream work. My favorite light rod is the Sir D, especially in Quad configuration (Bob Maulucci's version).

I'd run the taper thru Hexrod, adjusting first for the line weight conversion, then run in through a second time to do the hex to quad conversion. 

For those of you who don't have a computer but do have a hand calculator:

Divide the AFTMA #3 wt standard by the AFTMA #4 wt standard, to find out the percentage difference (the value will be unitless, but will give you a percentage how much less mass the 3 has compared to the 4).  Next, convert the diameter of the original taper at each station to cross sectional area.  Now multiply by the conversion factor to reduce the #4 cross sectional area values at each station to a #3. Finally, convert the area values for the #3 back into diameter.

In practice, this comes out very close to the values generated by Hexrod.  (Chris Obuchowski)

Great plan + a bunch of extra stuff.

I AM losing it. I was searching for a from scratch method.

For instance, how do you define the butt dimensions to get the punch, the tip for delicacy of presentation and stupid stuff like that.  What range of stresses, how much transition and where.. never mind  he he

By the way Dave's suggestion of a Hardy caught me off guard, I ran some stresses on it. It looks like a really neat taper, casts a 3 wt at 40 ft and a 6 wt at 50' and the stresses all stayed in range. Neat.  (Jerry Foster)

Okay, from scratch then.

Start at the ferrule station @ 42", and plot a straight taper forward to the tip dropping say:

.014/5"
.0171@42"
.166@40"
.152@35"
.138@30"
.124@25"
.110@20"
.096@15"
.082@10"
.068@5"
and we'll fudge to give .060@0", the tip top, a #4

Now go larger to the butt:
.179@50
.193@55
.207@60
.221@65
.235@70
.249@75
and a constant .250 under the handle.

How do are  stresses look?  Actually, they look great - nice smooth curve, max of 209K at 10", 189K@15"

Anyone could build this taper and be very happy; a crisp medium fast 7' 3 wt, smooth progressive action.  But, the client wants a slightly stronger butt to the rod, to really punch out that 3 wt in the wind (okay, whatever).

So now we add the Powell A concept, with a constantly increasing slope (we'll keep the tip section constant, a B taper; the C taper had a constantly decreasing slope to generate a parabolic type rod).  EC often used a .___ + 2 , or a two ten thousandths of an inch increase at each 6" station (we'll use .0003/5" to increase the power in through butt.  Our     slope     now       becomes:

.014+.0003@50"
.014+.0006@55"
.014+.0009@60"
.0152@65", etc. 

The new rod dimensions become:

.060@0
.068@5
.082@10
.096@15
.110@20
.124@25
.138@30
.152@35
.166@40
.183@45
.197@50
.213@55
.227@60
.243@65
.259@70
.272@72.

If you want a more delicate tip, you can use the A system to decrease the tip diameter, or use a faster slope (.015 or .016/5"); I'd recommend the second option over either (giving you a B tip and an A butt).  With an A tip I'd worry about weakening it too much.

Now what do you think?  (Chris Obuchowski)

Ain't this great stuff?  I still think the customer was smokin' crack wanting a 3 wt wind rod.  But hey, it's his/her money.  Is it normal to start at the ferrule?  If so, how much does making it a 3 piece complicate the works?  (Mark Wendt)

It was interesting to superimpose your compound taper on mine (explained below), even though mine is 6" longer (the tips are very similar). I think it would be interesting to make the rods and compare the actions. I suspect that yours would be faster but mine might have more "reserve power." Both should cast fine in my book.  (Doug Easton)

There's that term again!  Would you mind defining what you mean by "compound taper", that's one I keep seeing but can't quite make up my mind what it means. I get progressive and parabolic, but compound seems to elude me. (John Channer)

ROFL! As Jerry pointed out, we don't all speak the same language. I know in my mind what I think a compound taper is, but I'll let Doug tell us all. I'm never sure that my explanation is correct, I once spent half a night arguing with some guy over what a hinge was.  (Larry Blan)

You guys must know the meaning of hinge in dictionary better than me. Hinge is the point where the bonnet of your  car is attached to the body. Sorry.

The hinge on a fly rod is a special term which  connote some specific action of a rod, or some special feeling of action of a casting.

My understanding came from this.  While I was flipping and flopping a rod with the line in about 30' or so, the rest of line are in my line hand.  I was walking up through a small stream watching the next casting point. There were many 1 feet size stones paved over the river so very slippery. Sometimes I lost the consciousness that I was moving the rod by looking for the next to step on.  But I kept moving the rod back and forth.

Then I felt something!!!

By moving the wrist just a little bit, say half an feet or so, the rod bent and pulled the entire line in the air and it continues backward too. The bend is around the point where the second peak of stress curve is drawn, it's hinge.  At the point, the rod bows back and forth.

Considering this situation, I understood that the rod was in the first resonance  vibration situation, that is, the vibration of the rod just matched to the nature of the rod in translated rod motion.

So I understood that the hinge is the point on a fly rod where the rod would bow back and forth, like the hinge of the bonnet, when the rod is in translated rod motion, further to say when the rod is in the first resonance vibration.

Additive:

You know what is the second resonance vibration of a rod? When you wiggle a rod right and left quickly, the rod will shape like two parenthesis overlapped.  That  is in the second resonance vibration. The things have their own vibration nature.  When it is moved slower, it would match to the first resonance vibration.  When it is moved twice faster, it would match to the second resonance vibration, it depends on the speed of motion, that is vibration.

A fly rod may only can match up to the second one maybe.  (Max Satoh)

Let me try this:

"drop a fly on the water without a ripple"

As this is the technique of a caster, I would neglect. But the rod should have enough power to do this for 40'. To land the fly silently, the loop which a rod would make should rather be a little wider than narrow? ... uuum, it still ability of a caster.

"3 wt rod "

Okay

"punch 40' of line "

I have an measure of "feeling of a cast" which is done by the figures of percentage of moment.  Like this.

At the hand grasp, we feel an aggregate force of "moment".  The force includes the sum of moment caused from each component of the rod.

Then, total moment is proportioned to two major components.

I will see the percentage of moment caused by the "rod", which includes bamboo and all the parts, and  by the "line weight to fish".

If the percentage of rod is greater, it says that "the feeling of a cast" is rod weight oriented.

If the percentage of line is greater, "the feeling of a cast" is line weight oriented.

Then,  does "punch" mean that with less feeling of fly line,  the rod should forward the line?  Or does it means that the caster feels enough of fly line weight at handgrasp?

Then I ask the client, which would you like better between faster rod or slower rod? Probably, he would reply as "faster" rod.

Then, I will face to my simulator and adjust taper so that the moment proportion becomes "line weight oriented," place stress curve around or  a little below the flex line (to realize faster action),  to cope with 40' of fly line.

There might be some conflict between the element of "line wt oriented" and faster action.  In that case, hollow build may be an candidate.  The most stiff hollow build is quad with 4 strips?

I hope the resulted rod is lighter in weight, faster action, sharp feeling of a cast.  (Max Satoh)

I still consider myself a novice at rod making and have a lot to learn about tapers, but I feel the start is to get a rod in the customer's hand and ask to check his casting style (Ability). A great caster can do this with just about any taper but what can your customer accomplish? If the customer can't get the rod to do what he wants then it will be a bad taper to him.   (Gary Jones)

I'm wondering if Jerry's original question was intended to be hypothetical in nature (made up customer, rod needs, etc.) to stimulate taper design discussion.

Jerry, could you better articulate what  you were intending by your initial question?   (Scott Turner)

Here is my sort of from scratch approach to the challenge. This is why it is sort of from scratch. I only know what I like and what other people seem to like. I will call that a rod style. To punch a line out hard with a tight loop, I like Gene Edwards style rods. I have a 7’6” 3 piece 5/6 wt Edwards Favorite that is very powerful and seems to charm most people who cast it. However it is a bit too powerful for the customer from hell. It is also very fast; which impair delicacy by promoting too much line speed. Using John Bokstrom's "Rod Design by Controlled Modification" as implemented in Larry Tusoni’s RodDNA program to analyze the taper, the “Rod Action Value” is 0.344. This represents an average straight line taper of  better than .003”/inch of rise. I decided to reduce the average slope to about .0026”/inch of rise (still pretty fast) with a tip size of 0.065. I used Frank’s Hexrod to make a straight line taper of that slope. I worked from there to modify the straight taper.  I did 4  things around  that taper:  1. I made  the tip section from stations 0-20 a bit concave (lighter) to gain some delicacy (particularly at short range). 2. I note from several rods  that have smooth actions and have good reserve power (Edwards, Granger, and the Sir D series have strong middles) so I made the rod somewhat convex in the middle, such that it uses a 12/64 ferrule. 3. I added a small hollow near the butt for better roll casting and (I think) better feel. 4. I put the modified taper through Rod DNA and checked the RAV and LWV. The RAV was nearly .315 (too steep) and when I looked at the maximum stress in the tip section it was > 250,000 PSI, so I generated a new rod model with a RAV of .275 and adjusted the Line Weight Value down from 0.058 to  0.054. This yields a rod with n average slope of 0.0026 in /inch rise and a maximum stress of about 225,000 PSI.

So how does this rod compare to others of the same length and approximate line wt.?  Well, without trying to do so, I ended up nearly duplicating a 7’6” Winston  which is in the rod DNA database.  Maybe John Gierach is right about one thing. “ All the good tapers have already been made.”   (Doug Easton)

This is about the clearest illustration of the relationship between small, subtle changes in the taper and the resulting changes in the stresses.

Combined with Doug’s explanation of how he arrived at the resultant rod.

This can be a baseline to discuss the stress curve. (Jerry Foster)

I'd be tempted to add some at the 5" station, bump the ferrule stations a bit, and level out the butt just before the grip. Then, I'd see how far from looking like a Para it really is. (Larry Blan)

I wonder if your request for the Design on the rod taper you described, I think it was a 2 piece 3 wt, is over, and if so how many replies did you get. Did any of  them meet your requirements, and if so, how did you determine that they were correct or incorrect. 

I think designing a rod using only a description would be very exciting thing, I don't know of anyone who has done that. If you could summarize the results of the tapers that you got I'm sure everyone would be very interested, I know I would. (Bob Norwood)

The question was more rhetorical than real, I have no customers, I was trying to stimulate those who have  a process to explain it. Not a making process, a design process. You witnessed most of the dialog, and I have now doubt that any of the processes discussed will work.  (Jerry Foster)

Since you asked the question. I, and I think many others thought you would tell us if the tapers were indeed 2 piece 3 weight rods that would throw a 40 foot line into the wind? This would be quite a feat to design a rod from a description. I don't know of many Makers who could do this, so my question is still, did the two designs really meet your requirements? I know that these makers put a lot of time and thought in to their tapers and to say that your question was simply rhetorical leaves me knowing no more now than I did before. The Question seemed real enough to me and I would think the answer should be also. Why ask if you can't answer?  (Bob Norwood)

My original intent was to stimulate a discussion about how to evaluate stress curves for the purpose of rod design and evaluation.

A few offered their view on  how they use stress curves. Chris O. asked me for my opinion, and I believe I posted that.

It overall ended up showing the diversity of opinion and process that I  expected.

I did not mean to mislead anyone into thinking that they had to define a taper, i was more interested in how they used their process to reach their conclusions. This was more of a follow-up to Wayne's question than anything else.

I think we got to the heart of rodmaking however, several of you discussed their modification or initialization process, and that was great. At a certain point I think we reached the place where the process was considered personal and proprietary, or too esoteric for anyone else to comprehend.  (Jerry Foster)

Your intents made a great success in drawing our, especially my, interests in viewing and posting what we have been doing. I guess it is more than tough work with stresses to receive various kind of punches.  I thank you for Jerry to have done it.

Don't you guys think so?  (Max Satoh)

Good stuff.

Now for fast. Is the height of the tip stress, the length of the descending curve, or the stress in the butt the deciding factor?

How about loop control. I think we know that the power factor is the wrist, wouldn't a high curve dictate a flexible tip which should translate to lots of tip movement..ergo..open loops? (Jerry Foster)

Empirically, my opinion is that a more uniform stress curve, without the "tip action" peak, should result in a more open loop (though a good caster can control loop size with any action rod).

For example; parabolics tend to have relatively low stresses in the tip half of the rod, and seem to throw a more open loop in the hands of an average caster.  The more "tip action", IE. "faster" rod, seems to throw a tighter loop (in the hands of an average caster).

Anyone agree?

On the other hand, "tip bounce," which I think you see more often with "soft tip" rods, can interfere with loop control.  A soft tip is more likely to collapse during a powerful cast, limiting distance severely.

I would suggest that it is the slope of descent from tip to butt that is the indicator of power (a more gradual descent means more power coming more uniformly from the length of the rod, rather than the rod having a "hinge").  (Chris Obuchowski)

I agree with you IF you look at the casting stroke as a strobe action.  But the casting stroke is a constantly changing form, and what happens before and after any given point in the casting stroke will influence the whole.  I have seen different casters with the same rod ( a parabolic of my design) make drastically different loops.  One Threw a loop so wide open that he only cast about 25-30 feet.  And he  is a certified FFF Casting instructor). Another cast the whole length of the line with a wee little bitty loop.  He was not an FFF casting instructor.  Any analysis of these two guys.  I am still convinced that the big dingus hanging on the end of the cork handle is the most vital controlling force in casting a fly line.  I even have a very good friend who can cast the entire length of a fly line with no rod at all.

Empirically, I'd opine that a more uniform stress curve, without the "tip action" peak, should result in a more open loop (though a good caster can control loop size with any action rod).

For example; parabolics tend to have relatively low stresses in the tip half of the rod, and seem to throw a more open loop in the hands of an average caster.   The more "tip action", ie. "faster" rod,  seems to throw a tighter loop (in the hands of an average caster).

Anyone agree?  (Ralph Moon)

I think another way to put it would be that rods whose effective length (length under load) is longer throw tighter loops than one's whose effective length is shorter.

Fast, tip action rods have a longer effective length while casting and thusly can more easily throw tight loops.  Parabolics, having a much shorter effective length due to significantly more flex in the rod, don't do tight loops as easily.

The Dingus definitely has the final word though.  (Chris Carlin)

I think another way to put it would be that rods whose effective length (length under load) is longer throw tighter loops than one's  whose effective length is shorter. 

Chris, I agree with all my heart, You have it right, BUT

Fast, tip action rods have a longer effective length while casting and thusly can more easily throw tight loops.  Parabolics, having a much shorter effective length due to significantly more flex in the rod, don't do tight loops as easily.

I must disagree most vehemently with the next paragraph, but then I don't know what you mean by effective length.

The Dingus definitely has the final word though. :D

I don't know the dingus, but if by that you mean the caster, I am with you.  (Ralph Moon)

My definition of effective length is the length of the rod from the hand (or perhaps even better from the elbow) to the tip of the rod as it is in a casting motion under a load.  A slower action rod bends more under the same casting circumstances and thusly has a shorter effective length than the same size rod in a faster action.

Of course the effective length is going to vary depending on where in the casting stroke the measurements are taken, but the easiest generalizations are made for a rod under maximum load, at or not long after the beginning of the fore stroke.

It seems to me that the more change in the vertical distance that the rod tip has to travel from the point of maximum stress (beginning of the fore cast) to the point of minimum stress (middle of the cast), the more open the loop wants to be.

The assumption is also that I'm talking about rods of the same 'real'  or static length when doing an action comparison.  I'm certainly not saying that a longer rod will necessarily cast a tighter loop than a shorter rod, and I wholeheartedly agree with both you and Ray that the caster is the final word,.  As such, I think that we're actually saying nearly the same thing:

"For example; parabolics tend to have relatively low stresses in the tip half of the rod, and seem to throw a more open loop in the hands of an average caster.  the more "tip action", IE: "faster" rod, seems to throw a tighter loop (in the hands of an average caster)."  (Chris Carlin)

I have frequently argued that the rod action and the line taper will demonstrate to the caster what is necessary to produce a successful cast.  If this requirement is compatible with the caster's ability and casting mechanics, the result is pleasing to the caster and the designs are considered good.  You could probably program a robot to wield the proverbial broomstick and produce great casts but with a motion that no person could or would want to duplicate.  (Jim Utzerath)

It seems to me that the tip of the rod  (maybe the top 10-15 inches) really works different from the rest of the rod, and the design principles are therefore going to be different.  Is this correct? I'd like to see a discussion of how to design a tip that will work with the rest of the rod.   I'm planing a tip tomorrow and its not too late to change the forms.  (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)

You've raised another very interesting issue re the first 10 or 15" of the tip section and how to design it. Let me refer you to page 272 of Garrison's book where he advocates making the first 5" a bit stronger than design because of the high stress in that area and proposes to draw a mostly horizontal line from 5" station to the "0" station. I have done that on most all of the rods I've made and have had no failures in that area. I did have one rod where the tip section splintered about half way between the tip and the ferrule but that was because my black lab "Moon" (no offense Ralph) jumped into my boat and landed on the rod.  (Ray Gould)

This has really been an interesting discussion. I'd opine that I'm in agreement with Chris regarding the slope of the stress curve from tip to butt indicating power (energy being used). If one looks at the comparison of stress curves for a straight line stress compared to a parabolic or semi-parabolic stress curve you will see that the stresses are higher in the last 20" of the butt section for the parabolics. In casting I feel that because of this I have more of the rod working for me and it's easier to cast. Now loop control is another matter. At the Great Western Rod gathering at Dunsmuir we had a casting instructor demonstrate (with the same rod) how to control the loop size which makes me think it's more technique than design. (Ray Gould)

Chime in with your work/observations on slope of change in dimensions predicting rod "speed". I agree with what you've published, and have both of your books, and what's more it agrees with my observations from graphing and casting rods.

I also agree (I think you said it in one of your books) that you need to look at average slope over the "working length" of the rod, and discount any fudge or deviation at the tip and butt (usually the first and last 15" - 20").  (Chris Obuchowski)

If the line follows the tip, if we agree on that, then how does a tip with a high stress 220k, flexible, naturally throw a narrow loop?  (Jerry Foster)

I think that in the case of very fine tips, what happens is the the tip folds over and gets out of the way and the rod effectively shortens itself to where it is stiff enough to push the line. Garrison designed his tapers with 3 tip diameters and said he recommended either the medium or heavy tip, and I can't argue with him from my experience. BTW, thanks for starting this conversation, I'm sure I've learned more today than I have in a long time.  (John Channer)

This is the effective length that was mentioned earlier. The tip bends more, the "shorter" length of rod describes a shorter arc, therefore produces a tighter loop, all else being equal.

Some time back, Darryl Hayashida did some work on tips and came up with a set of dimensions that he felt threw a tight loop naturally.  I don't have the dimensions handy, maybe Darryl is reading.  (Larry Blan)

While I was sleeping,  discussions heated up to interesting level.

First of all, my understanding of narrow loop or wide loop of cast fly line is, how the caster moved the tip top.

It is free from whether a rod is stiff or soft. A stiff rod can easily make wide loop if you turn it from 0 degree to 180 degree. 

I am sure the stiffness of a rod surely has a tendency to make narrower loop if the caster follow the instruction of ordinal casting style.

I believe that the loop width is the function of tip top movement, speed of tip top (that is line speed), and a pair of heights,  from the height where the tip top is most accelerated, to the height where the tip top releases the line.

Sorry, moment matter again.

Moment is a force which try to turn a bar.  Moment is the force which works perpendicular direction toward a bar. So, translated rod action (Don Phillips word), would gather the most moment at the grip of a rod. If a rod is in rotated rod action, though tip top moves longer travel, but grip does not move so long.  It happens in the same time frame (time length).  In this case, tip part will receive relatively more acceleration, resulted moment and resulted higher stress, then it becomes tip action type rod for a moment. Butt side section would not bend so much, but tip front would bend much, even if it has parabolic taper.(problem of degrees)  If we can know how the tip top behaves, we can adjust the height of tip top at the line release in a casting motion.  It will make a narrow loop or wide loop.

Of-course a rod has tendency.

A food for thought.  (Max Satoh)

We all really appreciate your information and knowledge.  I hope you have devised a better rod design program.  Outside of that, I was trying to focus on the last of your statements:  "Of-course a rod has tendency."

Assume same caster, same stroke, different taper, how do we predict what the rod does.  (Jerry Foster)

What I meant was, though the loop matter is so and so. Rod has tendency which  make a loop narrower or wider.

Soft rod (slower rod), will bend more during the cast.  It will delay the tip top movement than the faster rod.  It also mean that the line speed is not accelerated enough while the rod is under bending motion, right?   When the fly line is getting more acceleration? I guess it is when the rod starts unbending, probably when the wound up moment is released and when the rod return to almost straight position. Slower rod has longer time from full bend situation to straightened. This delay may cause some feeling to a caster. Further, since slower rod bend much, so called effective length of the rod is shortened much. When the caster stop the rod motion, the slower rod start unbending and turning around the grip with larger arc.  In larger arc, the tip top will follow the arc line. Thus tip top will have a pair of heights, highest and lowest, wider loop will be resulted.

Faster rod has less up down of tip top movement. On faster rod, the fly line start accelerated earlier than slower rod. While the faster rod is not fully bend, fly line start going forward. Since the tip top of the faster rod does not go up and down much, fly line has tendency to make narrower loop. And maybe, the caster might feel that it is rather easy to control the line.

An experienced old caster like me, like slower rod and enjoy how the line is speed up by the unbending force of the rod.  I like wider loop since it is safer from making line trouble.  (Max Satoh)

Thank You to all involved in this discussion. The responses have all been insightful and educational. We are all indebted.

Scott:

I hope it was hypothetical, and no I'm not on drugs this morning, yet.

If you know me you know I only build 5 wt's. If I tried to build a 3 wt. it would end up as a 5 wt.

Seriously, I believe we have surfaced at least 3 very good processes on the development of tapers.

These makers have an extraordinary  amount of talent and insight. The rest of you who are simply watching but interested should not pass up the opportunity to ask questions.

My overall intent was to try to raise awareness of some of design tools available. I am convinced that the best tool is a working mind. I am still trying to stress the value of stress curves, but some of the directions taken are much more tangible.

Now if I may;

It is very obvious that we do not have a common terminology to speak of tapers, so everyone is left to their own understanding and sense of feel as to what some of this means. (thank you Larry)

It appears that no one uses stress curves as a basic  design tool.  (I know some of you do).

Now, suppose we get this guy (the 3 wt one) in front of us before we make the rod.  And upon evaluation of his casting style, discern that he has a wimpy wrist. Or any of them casting maladies that effect we normal folk. Is there any adjustment that you would make to the rod to compensate? Aside from a casting class.  (Jerry Foster)

It appears that no one uses stress curves as a basic design tool. (I know some of you do).

Oh no, without stress curve, we cannot understand the entire balance of stress nor identify the line weight. I always verify my rod by looking at stress curve.

Now, suppose we get this guy (the 3wt one) in front of us before we make the rod. And upon evaluation of his casting style, discern that he has a wimpy wrist. Or any of them casting maladies that effect we normal folk. Is there any adjustment that you would make to the rod to compensate? Aside from a casting class.

Ahhha, this guy looks like me... I do not have strong wrist.

So the condition is quite different from the last case.  For weak wrist power, I usually select such a rod that a caster can throw the line only by wrist.  By just moving the rod a little forward, or by snapping the rod just a little, the rod would deflect. There also need some considerations about this rod, it should have soft tip to be balanced with the flexible butt.   The butt must endure  when he hooks a big fish, then I would implement a little swell just in front of the grip.

I would assume the rod is 7'6" for this guy.  This time, I assumed that this caster would require some additional power which is helped by the weight of the rod itself since he has wimpy wrist.  So, what I call "the feel of a casting" is rod weight oriented.

As most of you already knew, I will draw a stress curve (assume Garrison's stress curve).   I put a red line around 8,750 PSI (pound/sq. in. almost 140,000 oz/sq in.),  this is the possible flex line.  If the stress is around here,  the rod  normally flexes at the point, this is the rule of thumb.

I would draw such stress curve:

* draw a straight horizontal line just above the flex line around 9,000 PSI.  This means entire rod would evenly bend.

* implement a peak of stress curve at 20 inch point,  about 13,500 PSI.  This means tip will flex enough.

* implement a swelled butt from at pt 73" (17" from butt end) 8,000 PSI to pt 80" with 6,000 PSI.  This makes it easier to control entire rod and endure with strong power of a big fish.

* implement so called a hinge(second peak of stress mountain) for wrist casting at 60" pt with 11,000 PSI.  This will help a wimpy wrist can cast this rod very easily.

* moderate the stress curve in between the points above.  Smoother curve would result in smoother feel.

Frank Stetzer's stress curve drawing chart can moderate this automatically.

Then I make it to dimension.  Then I make the stress curve from the dimension again for verification. This is to my case only.  I will draw a deflection curve and simulate with various situations, quick cast, slow cast, pick up, hook the fish, etc..

Then this is done by every body, take the moment values of each rod component at 80" point which is in front of grip and take the  percentage of 1, line to fish, 2, bamboo (and other parts).  Try to compare to each other, which weight are larger?

This rod may become nearly equal to Payne L200 8' feeling.  (Max Satoh)

I do indeed use stress curves as  my basic design tool. I use the Garrison stress curve for most pentas and Zimny's stress curve for quads. Garrison's stress curve works also well for my trirods.   (Bill Fink)

As the relatively abrupt stop to set up the loop is intrinsic with casting, there is likely no cure but casting instruction.

Note: I said relatively abrupt stop. I find a good solid stop hard to do when "just fishing" and tend not to keep the loops as tight as possible so I guess it is off to casting school for me.  (Don Anderson)

There is no doubt that there are different casting styles and that different rods suit different casting styles. The expert casters are experts, however, because they can adjust their styles. They can adjust loop size primarily by adjusting the path that their hands follow and the acceleration of the casting cycle to compensate for the rods characteristics. This is why some casters can cast tight loops with parabolics whilst other struggle.

In order to really design a rod for a caster with a fixed style it would be critical to plot the path of his/her hand and the acceleration of their casting cycle. The distance the person casts would also have to be predetermined as the acceleration and acceleration period is different for different distances. The rod could then be suited to the person AS LONG AS THEY MAINTAIN THAT STYLE and cast mainly to that distance.

Surely a better process, all else being equal, would be to design a rod that assumes that the hand will follow a straight line (as advocated by many respected casters) and that the caster will learn to do so. This would then leave the choice simply as to what kind of loops the caster wants the rod to naturally throw and, to an extent, what the feel will be as a result of this choice.

Personally I find it easy to throw open loops, when this is required, with a rod that 'naturally' throws tighter loops (Chris Carlin's 'longer' rod). I can do so simply by slowing down the stroke (at least it feels like that although what is probably happening is that my hand path is dipping). On the other hand I find it more difficult to throw tight loops with a rod that naturally throws open loops (Chris's 'shorter' rod). This is because the hand path has to assume the correct curve with the correct timing (which is also faster) to keep the tip moving in a straight line. I think many people have similar experiences in this regard.  For this reason I prefer fishing with faster rods - they give me more options. How fast the rod is depends on the fishing conditions. There is nothing to beat a really fast rod when punching big flies into the wind is required.

In considering a truly empirical basis for designing and comparing rods I can't see how this can be done without computer software. I imagine the following would be critical issues in any empirical approach:

1.. The Elastic Modulus of bamboo would have to be determined or (unfortunately due to lack of research and variation from culm to culm), guesstimated.

2.. The same heat treating and rod finishing regime would have to be used

3.. The weight and placing of rod components determined

4.. As Max Satoh explains the rod would have to be considered dynamically, or at the very least assessed at fixed points in a casting cycle rather than at one point only.

5.. The casting 'style' would have to be fixed. e.g.. assuming a fixed rotation point, a fixed amount of hand movement in a fixed direction and a prescribed arc through which the rod moves in a prescribed time. (These could be varied for different assessments but would have to be fixed each time for  'apples with apples' comparisons)

6.. The force of the line (mass x acceleration) would have to be determined for each point in each cycle.

7.. The criteria of assessment would have to be prescribed egg. width of loop, recovery time at end of sequence etc.

8.. The criteria of assessment would have to be prioritized in order to assist in selecting the best design for the purpose .

Failing the computer software approach to design, the next best would probably be an experienced caster/rodmaker (Harry's point) starting with a design and applying a process of trial and error to refine it. This approach was probably used by most of the classic master builders.  (Stephen Dugmore)

As smug as it makes us bamboo nuts feel to disrespect our graphite brethren, right now they are far ahead of us in analyzing and systematizing (sp?) your points 5-8.  (For some reason the number changed when I snipped the post).

Sage has recently introduced a casting analyzer which is likely coming soon to your local fly shop.  Basically it's a gyroscope attached to the butt of a Sage rod and wired into a handheld computer.  It analyzes the motion of the rod being cast and compares it to composite baseline cast based on a panel of 20 experts ranging from Bruce Richards to Jason Borger to whoever else.  It measures such things as rate of angle change, degree of smoothness in acceleration, and so on.  I tried the analyzer in October and found it quite interesting.  It isn't a perfect tool, but is a great learning aid.

One thing it does well is force you to keep things simple.  Exactly forty feet of line beyond the tiptop is strictly controlled.  Hauling, double or single, is not allowed.  Thus it  monitors the criteria you highlighted in capital letters.

Our own Frank Paul has done some fascinating work analyzing both rods and casters.  He gave us a small glimpse over the weekend, and I hope we'll be hearing more about it in days to come.  (Harry Boyd)

Let me throw a monkey wrench into your interesting discussion on rod taper design.  Lets suppose you have designed a rod with a given taper and it has a fundamental modal (the static shape of the rod with a small tip load) frequency of lets say 2.5 Hertz (that is 2.5 cycles per second or 150 cycles per minute) - a medium speed rod. This fundamental frequency mode is the bending mode that you see when casting a fly rod.  Now this frequency is determined by rod design taper and EI stiffness modulus distribution along the rod. Remember the rod is a tapered beam and behaves not as a linear cantilever beam but as a nonlinear cantilever beam - this means - given a static load of 5 oz the tip deflection might be  'x', while if I double the load to 10 oz the tip deflection is not '2x' but something else.

So now I put a line on the this tapered rod design and put it in a fly casters hand who can hold the rod with out any elastic behavior between a hand and the rod grip.  I now look at the fundamental frequency mode of this flyrod,  line,  and caster -  A FLY CASTING SYSTEM - and the this mode drops by about 40 percent - that is it is 1.5 Hertz.  Quite a change that you may not think exists - but it does in reality. Now lets decide that the fly caster can not hold the rod so tight that there is elastic behavior between the rod grip and hand. Now looking at the fundamental frequency mode of the 'fly casting system' it drops by about 50 percent - that is it is about 1.25 Hertz. 

Now given that the rod taper design and line have not changed, what causes this difference? It is obviously the caster - and since each one has different arm  and body strengths and developments, the behavior  of the flyrod casting SYSTEM changes. Now how do I know that. Well, recent completed research (my efforts at Clemson with a graduate student) that models a fly casting system demonstrates this phenomena which most 'old fart casters and rodmakers' have known for a long time. 

So what does this mean for fly rod taper designers? You better factor in the unknown casters physical capability in designing a rod taper to fit the caster and selected line - if that is your goal. This is obviously the reason when we have a Payne or Young or Dickerson or whomever, that one caster likes one rod better than another. Remember that when we are younger we like faster rods and as we age we usually like slower rods - physical abilities change and influence what we like in a rod design.   What have I learned - I think engineering analysis methods such as Garrison used guide us in taper design, but there is no way that we will ever create the ultimate flyrod design computer program to custom design a flyrod for "Old Joe".

Hope this adds to the discussion and stimulates some new thinking. My student and I have submitted two papers to an International Journal of Sports Engineering. Hopefully they will find the results of this work useful enough to publish after appropriate review.   (Frank Paul)

OK, I suppose I can agree with everything anyone has said, except the need to invalidate some engineering principals in rod design.

Here is a premise I guess I didn't throw out but I thought was understood.

To use any system (other than touchy feely) one must have some constants.

So the assumption was (is) that the rodmaker, glue, varnish, are all constants. I know these are all variables but for the sake of design there must be a standard for each maker.

The Bamboo taper itself was to be the only variable.

yes, we all know that bamboo is a wonder of nature and not a constant, but I dare you to put that in the equation and ever finish a rod

I think the topic of casting is another great subject.

Tiger Woods can probably drive 250 yards with a polo mallet as Steve or Jason can shoot a full line with a broomstick. For the purpose of understanding rod action that's probably not relevant yet.

OK for the non believers in the Garrison, what alternative is offered, this in not a challenge but a real question.

We are looking for predictability and repeatability.

I guess the only unknown in the stress methodology is the cane must be tempered, and as Garrison was using Payne as a prototype, It might be nice to now his heat treating regimen, but I don't think it matters as long as you have one. Another constant.  (Jerry Foster)

Well stated. And thanks for mentioning the fact that a rod is a nonlinear cantilevered beam. It is exactly that which complicates everything we're discussing here. And you're right, one must design each rod to suit the customer. I have the customer lawn cast the rod before purchasing to be sure he or she is satisfied.  (Ray Gould)

I guess my entire understanding of the rod action during a cast is invalid.

This shorted beam aspect might be relevant. I haven't quite come to grips with that yet. I do understand from visual and internal stress standpoint but...

Are all who support this dynamic telling me that the tip of the rod does not pass from a totally flexed position (for a given amount of power applied) during the loop forming part of the cast to a normal straight, or maybe even over flexed, position during the power transfer (stopped position). Or that the line does not follow the tips path.

It would seem to follow this logic that  also the more the foreshortening the more the flex? the greater the loop?

All else being nominal.  (Jerry Foster)

I think that is the way most rods do work, but I thought you were asking about rods with very fine tips. I've had a few Leonard's and Payne's in the shop as well as a couple of rods I've made myself that had very fine tips, as small as .044 in the case of one of the Leonards, and they all had a "shoulder", or rapid rise in the taper not far from the tip, 10" -15" in the case of my own rods built to 5" centers and between 9 and 12" in the case of the Payne and Leonard rods, which I'm told were built on 3" centers. When I watch these rods in action, it looks like the part of the tip in front of the shoulder is following the line, not leading it as a stiffer tip would. Though I liked the way the rods cast, I did wonder why the tips were made so light. The rods I made were experiments, but the other's were regular production, I guess I missed the point.  (John Channer)

Since Payne and Leonard used beveling machines, I believe they worked their tapers on 1" centers.  I'll have to dig up the stuff I got from Hal Bacon.  Included with the pictures and stuff I got from either him or Todd Talsma on his presentation at Grayrock this year, was a couple of graphed tapers, and I'm pretty sure they were done on the 1" centers.  (Mark Wendt)

Kusse told me 3", I figured he would know. It would pass expectation for Ron and Hal to agree on anything though.   Are the graphs  you have originals? I for one would love to see one.  (John Channer)

What line forces acting on the guides might they be then?

If the load is applied at the tip it is applied to the whole length of the beam from tip to butt.  If the cord you use to apply the load is tied to the tip ring, the butt or the reel it makes no difference, it cannot move, the load is the same, the deflection is the same and deflection is directly proportional to load, whether you like the laws of physics or not.   (Robin Haywood)

You are correct, I was not thinking correctly about the line forces on the guides being internal to the rod line system. Sorry I may have confused some folks on the list. I do like the laws of physics, so correctly applied and thought out, there is no problem.  (Frank Paul)

Sorry I can't agree with you on this one.  There is a definite difference on how a rod deflects depending on where the rings are placed.  There is no change to the externally applied load so the net moment is the same and as you say if you do the quarter turn (test curve?)  load check the answers will be the same whether the line is tied or threaded.  But, and I think its a big but, the deflected shape of the rod will be different due to the resolved forces at rings.  To preclude protracted debate I have done something I have meant to do for a while which is to undertake the experiment you outlined in an earlier post, the results can be found here.

The photos can be found by scrolling down to the bottom of the page.

I used an old solid glass tip that I could abuse with impunity and plotted the deflected shapes with the load applied; tied to the tip ring, threaded through all rings, center ring only and tip ring only with the line tied at the butt end.

As can be seen the deflected shapes are all different.  This will make a difference to how the rod feels, if it didn't you might as well say that all tapers that have the same test curve are the same to cast,  when clearly they are not.   (Gary Marshall)

I think both of you are correct as are my previous comments. Let me try and explain my thoughts that are clearer this morning than last night. On the overall tip deflection of the rod, there is no difference in whether the rod is loaded by the tip only or with a line from a reel that goes through the guides and out the tiptop,  the deflection of the TIP is the same - I hope I corrected my misthoughts from last night.  As far as location of the guides, this will influence the local deflection behavior of the tapered rod but not the TIP deflection. The difference in these two models is that a tip load has no internal guide loadings and is considered a point load source at the tip. When a line is used to load the rod there is a distributed point loading along the tapered rod beam. . If one resolves the forces at the guides by cutting the line on both sides of a guide, the guide changes the direction of the line force (not the force magnitude) as it passes through the guide. Because the line angle changes, the line force direction changes  (assuming no friction  between the line and guide) and produces a local load on the rod through the guide. I hope this explains what I said last night and suggests that you both are correct  in  your  thinking  about  rod loading.  We need  to just  remember that  the line-guide forces are internal and do not influence the TIP deflection for a given load but the guide locations do influence the distributed local deflection of the rod.

You can test this situation by putting a reel on a rod, and in one case put the line through all the guides and tiptop and then only put the line from the reel through the tiptop. Both of you will see where you are correct. In both cases the TIP of the rod will be at the same location for the same load, while when  you compare the line through guides and line not through guides the local deflections of the rod are totally different.

Hope this helps - sure did for me to write it down and think it through and run a test in my shop with a soft "plastic rod".  (Frank Paul)

A nice explanation.  I concur and I hope the photographs I posted also make this clear  for those not so familiar with statics.

I replied to Robin's post because I felt it left the impression that guide spacing has no effect, in fact some earlier comments were quite categoric. Exactly as you describe the spacing affects the local deflection not the overall deflection for a given load.  It is this local deflection that determines the character of the rod especially the tip and why moving the rings around can improve the way a rod performs.  (Gary Marshall)

If I use the tangents on the outside edge of a tapered beam under flex (why I want to do this currently eludes me) do I get the same result as I would if I use the centerline of the beam? Which method might be more correct?

(Remember Robin, you said I could ask stupid questions)  (Jerry Foster)

Well, strictly, its the center line but the difference is so small that it gets lost in the "experimental minor errors" allowance. You will soon get a firm idea about what constitutes a quarter circle and all measurements using your rig and your view on a quarter circle will be compatible with all other measurements you make. It doesn't matter much what value you get for a #6 rod, provided you use the same method for measuring your #7 rod then you will achieve a constant difference, it is this difference, in percentage terms, that you will use to calculate what percentage increase to apply to the 5" stations to effect the desired modification to the rod to increase its line rating whilst preserving its action.

It is worth saying that if you produce a range of rods which are identical in every way except for their line ratings, you will probably find that you prefer some to the others.  This is a taper matter and confused by the fact that you will probably use them for different types of fishing. This phenomena becomes much more obvious when you use length as the variable! Small changes, like one line weight up or down or 6" more or less work well, beyond that the above personal factors intrude more and more.  Some rods are actually nicer when modified, or they will be to you, others may not agree.

Rods are like cars and women, even perhaps golf clubs, we all have our own preferences.  Life would be boring, even unhygienic, if we did not!  (Robin Haywood)

I did think that I had explained in what way guide weight and position may make a difference, but it occurs to me that this may have been in a private post that you may not all have seen.

Essentially, I can only claim that small differences in spacing make no difference, for that is all I have direct experience of, extremes may not follow this rule, but I can say that too many too heavy rings too near the tip can make a rod feel much heavier and much slower in action, how much this actually changes their casting performance I cannot comment on. I have many times replaced rings with lighter ones, retaining the same spacing and the rod has felt very much nicer as a result.  (Robin Haywood)

I can understand both of you are right.

Robin's saying is that in making quarter circle, guide spacing does not a big issue nor no effects on making quarter circle since the quarter circle is made just by the pulling force of the tip top. This is the fact. Whatever parts is attached on the rod, it doesn't matter. A quarter circle is the test how much power (strength) the rod has when it is bent in QC.

Frank's saying is right too when he refers to the rod in motion. It is obvious that moment is generated by every parts on the rod, nevertheless it's big or small. The moment generated will affect how a rod will deflect.  (Max Satoh)

"Someday, if we continue to evolve, someone can walk into a rodmaking studio and walk out with a rod tuned to them. A rod based on the performance criteria put forth by the buyer and further refined by the maker to take into account  casting style,  personal physic,....."

You can kind of do that now. Noel Perkins, a professor friend of mine at University of Michigan who is also into casting analysis and a fisherperson, has come up with a casting analyzer for individual rod design. The device uses a rate sensor attached to the rod butt and a "palm pilot microcontroller" to analyze a caster.  I understand that Sage has taken an option on this device and is going to use  it at their rod outlets for caster analysis. I have cast with the analyzer last year and found my casting style did not exactly match the "postulated ideal" casting motions that are used for comparisons. In fact, of four casters (I hope I remember the number correctly), only one of those casters was close to the balance prescribed casting motions.  An old FFMag last year has an article by Richards (of 3M line folks) and Perkins that discusses the device and the ideal casting profile - dynamic velocity profile of the rod butt in the complete casting cycle.

I have talked about this issue with another unnamed non-US "rodmaker" about how one provides a custom rod to the client in the store (he/she is not going to order one - remember custom sneakers didn't last very long because of the customer wait) at least 5 years ago.  The way you  do this is  make a bunch of multi-section rod pieces - butts, mid1, mid2, mid3, ---, and tips and put them together in the store. Now I am not worried about this because I have made a manufacturing cost guesstimate that the rods would need to sell in the well over $1K to stock the sections needed for instant customer satisfaction - my opinion only - even though the carbon fiber sections are dirt cheap when made in the Far East.  There would probably be a limited number of dealers that could afford the inventory of sections.  Let’s face it, the flyrod business is not that large, so capital investment does not sound like a good return on profit - remember the current problem with Winston and bamboo rods

I think "us bamboo makers" can just sit back and wait for interest in bamboo to return as you all have created an interesting distributed manufacturing sector in the US and other places in the world. This seems to me to be the only approach to long term survival of the bamboo flyrod manufacturing industry.  This has gotten too long. OK sorry for the long winded dump.   (Frank Paul)

This is an interesting idea, but I don't think it will ever really work very well.

I thought about attempting custom design a couple of years ago.  The main problem with Garrison's design theory is that it's static.  It assumes that the rod doesn't bend, acceleration is linear, and that all force is orthogonal to the rod axis.  This is a bunch of hooey.  It's possible, as a Max has demonstrated, to calculate the stresses and the deflection of a rod as it goes through a casting cycle.  It would also be possible to use a digital camcorder to digitize a person's casting stroke and solve for the taper that would translate that individual casting stroke, the path of the hand, flexing of the wrist, and angular acceleration, into a linear path of the rod tip for a given rod length, line weight, and length of line cast.

The problem with this custom taper is that it would be designed, not for the individual per se, but for the individual casting stroke that you recorded.  That casting stroke would have been influenced by the rod in their hand when the recording was made.  We all modify our casting strokes to suit the rod in hand, and the cast we are attempting.  The custom taper would be optimized for one possible cast that a person might make, and might be a really great rod for that particular cast, but pretty useless as a fishing rod.  A great fishing rod needs to be able to cast in close with delicacy, punch some line out when needed, roll cast, spey cast, mend line, fight fish, etc.  Theory might get you in the ballpark, but a really good rod will plenty of art, mystery, and magic in it too.  (Robert Kope)

An excellent example of rod design/function was the one-piece rod you had at the 2004 Corbett Lake Gathering. If I remember correctly, you had made it from a piece of  bamboo which grew in your backyard.  It was not split cane, but made from the natural stalk. It was also not quite straight, and looked a bit odd alongside all the fancy hexes and quads. But it cast quite well, although a bit quick at the tip. Perhaps a fine dry fly rod.   (Ron Grantham)

I agree with you about the caster of a rod will adjust his casting according to a rod.   This is the fact.

But it does not mean always that we should not have a tool to look into the effects of rod movement.

We can find out various facts from the simulation. May I list some of them up here?

* Picking up motion of a rod is very related with the rod weight since gravity works to bend a rod, in this case much of moment is focused at grip front.  Good cast depends on the previous movement. Good pick up motion will lead to a good forward cast.

* Rotating a rod in a forward cast,  at the last phase of casting the rod is already started unbending, though it depends how we should stop the motion.  Before stopping a rod, we are already casting, mostly.

* Otherwise we move the grip a little higher than forward movement, line would go under the expected direction.  This is because tip top moves like that. etc.,

I know your point.  It might be hard to apply this to a custom order of a rod.  Then you need not to apply this to custom rod building.

It would be a considerable enhancement if we can show our client how a rod would deflect in a motion.  We can discuss on other matters too on it. Compare it with nowadays status, there are many fishers who buy rods via internet without knowing the details. I guess they only identifies line# and length of the rod,  fast or slow and price.

My understanding of this rod industry, we should be more friendly to our clients.  Not product-out view, but more market-in view is needed. Though some makers are doing.  (Max Satoh)

Okay, here's a question.   I can understand that a static rod would bend the same with a fixed line going through all guides or only the tiptop.

What would be the difference if the weight was applied ONLY to the tiptop with no attachment to the base of the rod, vs. a line attached at the base of the rod passing through the tiptop? 

It seems to me, (without experimentation)  that there would be two different vectors involved here.   The first would be straight down, while the second would combine the straight down AND the resistance of the static line?

Of course, I guess if you bend a rod 90 degrees at the tip there's not going to be much difference in the bend, 90 degrees is 90 degrees.  (Terry Kirkpatrick)

Test it yourself. Indeed with a fixed weight 90 degrees is 90 degrees.

If you continue to pull on the rod tip it will flex more into the butt but retain the 90 degrees. Watch out for the tailing loops.

I know this does not answer any questions about guides, sorry, just static dynamics.  (Jerry Foster)

When you get this post, you must have the answer already.

1 PSI (pound/sq in.) = 16 OSI (oz/sq in.)  (Max Satoh)

I read folks talking about statics, dynamics, and static dynamics (an oxymoron).

A body in static equilibrium is either at rest or moving at a constant velocity.  That is sum F = mA = 0; obviously m is not zero so A is zero and all forces/moments must sum to zero on the body.

A body in dynamic motion has acceleration A that is not zero.  Same equation applies.

The most general model of bodies in motion is a dynamic model. The static model is subset of the dynamic model; that is when A is zero.

So Garrison is not totally incorrect in his approach to rod design; he has just used the static modeling approach and compensated the designs with his fudge loading factor.  Max Satoh has added the dynamic part to this static model that says the acceleration of the rod is not zero but changes as the rod moves from one place to another.  (Frank Paul)

One has to assume that Garrison knew this, but found that his fudge factor worked for the rods he liked to make, when he made them.

It is not necessarily ideal for the rods that we like to make now. In order to arrive at what any designer will think is to him a more appropriate if he is going to have to do some practical research, all the computer power in the world will do no more than help him do the sums quicker,  as I find I have said before,  as usual.  (Robin Haywood)

OK here's what I think about Stress's

This was Garrisons attempt to quantify the stress on the mass in bamboo in motion. MOI. The force acting against the rods natural Action is the weight of the line beyond the tip (+ other variables, which are constants). I have assumed that the force, human, required to move this mass rod + line is whatever is required. ( this part could certainly be fed into a more exotic program, along with dynamics and MOE ) The end result, would still be a static (best average) set of numbers so we can adjust our bars.

So this is how I view stress curves.

As some of you know I keep asking the stupid question, is this fast or slow? Most Bamboo makers talk about this in terms of rate of change through the majority of the rod, or extensions of it. Mr. Gould has a great explanation in his book. For me this is only valid if the rate of change is reasonably constant. All kinds of things can happen between a tip and a butt. But you will see this in the stress curve.

So speaking of stresses only... I make some assumptions. Garrisons limits 220k to 140k are a generally good range. Remember this has a built in 25% margin of error built in. And that the target rod has a specific line weight and and line beyond the tip weight.

The stress curve (Mr. Cattanach's dissertation) accurately depicts the Character of the Rod. Who is this Character? It is the type of rod, and some obvious inferences to action type. Parabolic, Double Para , Progressive, a straight line from tip to butt (Garrison, wave linear), Linear (that pretty little curve if we just put in a tip and a butt dimension) these are large vessels of classification, but it would give most of us an immediate feel for the type of rod action we could expect.

As refinements to this I think of the curve as a 3x3 array.

The X axis, left to right, is of course Tip, Mid, Butt.

The z axis, top to bottom is flex potential, or Stiffness.

If we wander around in the top 1/3 very long we can get really whippy, real fast. Soft.

The middle is the transitional phase, Most of the casting takes place here. It either accepts the stress from the tip or sheds it as fast as it can to the butt section. A 15, known for a stiff mid relies on the butt section flexing more so the butt is weaker, less cane, higher stress. the opposite is probably something like a osten 99 tourney.

a rod that gradually increases in stress mid to butt is trying to flex into the handle.

The bottom is of course the Stiff, fast, part of the curve. Rods which wander around in this area can vary from broomsticks to Dickersons.

A design that has a high stress in the tip with a rapid descent tells me the tip is shedding it's stress into the mid and the butt sections rapidly, fast tip, the depth of the descent can tell you how fast, or how weak the tip is (or out of balance)...A broad top to the tip stress shows the duration length over which this flexing takes place. this is usually accompanied by a gradual descent or leads to a more moderately flexible rod.

All of this is of course based on the overall z range into which it falls.

This not the book on this stuff, merely the way I look at it. It has been plagiarized from many sources and there's nothing new or original here.  (Jerry Foster)

I also plug in all kinds of line to cast lengths to gauge where the obvious limits of the taper are, I also use different line weights to the same end.

you just have to remember to hit the calculate tip impact button to get the proper picture. Chris Carlin developed a wonderful tool for this, as Paul Griffin is working with me on an update to exclerod. Max of course is doing his work and Wayne has an update to his groundbreaking work. Thank you Wayne. Larry Blan, and many others have also made contributions in the form of new features.

Please show me the error of my wicked ways  (Jerry Foster)

In my terms, there are several dynamics.  already talked? I might be Alzheimer...

One is static dynamic, the other is moving dynamic which is really dynamic, though the calculation method is same.

Static dynamic is like this;

Rod does not move, fixed to one place at grip end.

When a load is put on the tip top, the rod starts its deflection.

As time goes by, the load to the tip top would passed over to the next part of the rod.

This kind of dynamic (or we should say, natural dynamics) thing is to be calculated.

Why?  I want to have a natural movement of a rod.  When the tip front portion is straightened by quarter-circle load or overload, its stress must be zeroed. To catch up this effects, this type calculation must be implemented.

One more thing.  Even if the rod is in the rest as the grip is fixed and rod does not move, the rod has its own weight. In other words, the rod is always receiving gravity acceleration of 1G(=9.8m/secsec) at every part.  If we want to draw the deflection which is as similar as possible to natural movement, we have to take the gravity (acceleration) into account always. We can see this, even if the rod is in the rest, the rod is deflected just a little.

As Garrison multiplies 4 to every parts (bamboo, snake, ferrule, etc.) of a rod, he moves the rod in 4G acceleration in his assumption, though effective length is not reflected back to his moment calculation.  So, this is a kind of dynamic model. (sorry for confusion).

Moving Dynamics is the dynamics happens in motion.

Moving Dynamics are very complex and takes many seconds to calculate on PC, about 30 second for 5 shots of rod deflection. To calculate this, we have to assume how a rod moves. I can realize any rod movement by specification. If any point of a rod moves in a  certain velocity and to a certain direction, within a certain time, I can calculate the acceleration. Then I can calculate moment and stress values as well as deflection as a result.

Both of dynamics are complex calculation which requires so called a "recursive" calculation.

As Robin already suggested, I also imagine that Garrison already knew about this when he started using 4 as his factor.

Murmur of Everett seems like this;  "You have various dynamic calculation ability and you can draw various stress curves accordingly. By the way, how do you design your rod?  Which assumptions do you use?   Otherwise, I cannot compare one rod attribute to another. If some show me a stress curve which is calculated by 5G acceleration, I have to convert it to my standard of 4G. Do you use dynamic model?  No, it has too much variables to standardize and share with. Even static dynamic, we have to standardize several factors, such as rod motion (translated, rotated, extended arm), acceleration (3G, 4G, 5G), load of the ring? (fishing length). Let's have the standard as, motion is in translated, 4G  just meats to the need, and fishing length is just the load on the tip top. But I cannot do such long calculation by sliding scale..."

I realized here one thing, several taper archives carry stress curves of several rods.  The assumed line-length-to-fish are not standardized. Some rod has 40 feet, some rod has 50 feet.  The resulted stress curve has different height of stress curve.  So, let me suggest to Jerry and Frank Stetzer here, please implement line to fish standard, in such a way, for #3 rod, let's use 40 feet as standard, for #4 rod, let's use 45 feet as standard, like that. so that everyone can identify if the stress is above flex line or under with a standard load. This method would lead to Robin's line weight scales.  (Max Satoh)

Multiplying the weight of the front 30' by three is not going to give you the weight of the full  line unless that line is untapered.  Anyway, if, for some reason I totally fail to comprehend, you want the full line weight then why not weigh the full line? The maximum stress figure will be generated by the mass of the line multiplied by its velocity, the length, is irrelevant.

I might also add that a rod should be rated so that, in the hands of the rater, it bends no further than a quarter circle when casting. The line weight which corresponds to this condition is thus the rating of that rod for that user.  One of the few irritations of Hexrod is that I have to keep correcting the line length figure. For practical purposes 6' of line extra or less is one line size more or less, so, if you want to aerialize 12  yards of #5 line you use a #6 rod. This, you may feel is a very sloppy solution. As my old woodwork master said of his poor wife  "She ain't pretty, but she gets the job done".  (Robin Haywood)

The line weights as specified by the AFTMA are for the first and last 30 feet of a Double Taper line. They neglect the first one foot or so of straight line at each end, that leaves 28 ft of running line to weight. To me the weight of the 28 feet is close to the weight of first 30 feet of tapered and running line, so multiplying the AFTMA 30 foot number by 3 comes very close to the actual center weights for each line size. If I do it to all line sizes then any small error will be in the same direction for every line size and I can live with that.

Why I want the full line weight is to divide it by 90 feet and get the weight per foot. If you use Hexrod or any program like it you have to specify the line length outside the tip top, then multiply it by the weight per foot, that's what the 50 or 40 or 30 feet means. Right now there is no standard for line weight, Hexrod uses an averaged line weight measured long ago using who knows what lines. I think my suggestion would at least give us a standard, which we DO NOT HAVE now, if no mine then something should be done about the lack of a standard.  (Bob Norwood)

Does not the AFTMA scale give you the length per foot of the middle belly = level, bit?  I cannot understand why Hexrod does not just use the front 30' weight.  This is the problem with standards, the minute they are created manufacturers try and fudge them. What on earth might a #7/8 line be, for instance? What it SHOULD be is a #7.5, in practice it is a #7 that becomes an eight a bit quicker than normal when more than the usual 10 yards is extended. Why not call it a #7/30-#8/33? Some relative novices might understand it then.  (Robin Haywood)

Thanks for pointing this out. I understand your wording "static dynamic" now. I would just call this the dynamic behavior of the rod while fix on a testing bench - still dynamic behavior in my opinion and in the mechanics sense.

One thought I had overnight (a few glasses of wine helps at a nice dinner with friends) is that Milward is trying to recover rod stress data from an actual Casting SYSTEM (rod, line, and caster) while Garrison appears to design a taper based on the "static dynamic" bench rod (as you call it Max) with the included line and "fudge factors" for dynamic loading. Now I know that the dynamic behavior of a Casting System is different than the dynamic behavior of a fly rod on a bench.  There could be an issue here in  trying to compare stress "apples and oranges."  Just a thought.  (Frank Paul)

Now I know that the dynamic behavior of a Casting System is different than the dynamic behavior of a fly rod on a bench.

Though the assumptions for both behavior are different, exactly the same physics is working on both, by means of Physics.

The difference is whether the rod is moved or not. Gravity acceleration (weight on the earth) and acceleration by forth of inertia are both acceleration itself (Garrison's 4 is also considered as acceleration). They are exactly same thing since they exists in "Space".

There could be an issue here in trying to compare stress "apples and oranges".  Just a thought.

If people think it an "issue" or not, it depends on the people's standing. It is surely confusing if someone show a stress curve without explaining how it was generated, Garrison Static, Static-dynamic (my word) or dynamic in motion, etc.

Even among Garrison Static stress curves, it already happens as we can see in someone's post about Standard Line Length to Fish.

We should know about this and use the useful tools or methods with  wise and  relevant carefulness.  (Max Satoh)

We haven't determined the rod length. I would assume a 7 > 7.5' rod.

14.5"/5 would be quite fast in that short of length. I would tend to make the tip @ 14.5 reducing it to 13.5 from 30">50" and then increasing it again near the butt.

Some rules of thumb that I've used. 12.5/5 in shorter rods <7' to 14.5/5 in longer rods > 8'.

The extra overall OD is required to "carry" the extra cane.  (Don Anderson)

The rate of change from tip to end of working length of the rod should be expressed as 0.012>0.0145/5" of rod travel.

OD= flat to flat

working length = tip to start of swell if any

To calculate the rate of change:

Butt OD - tip OD/working length in inches*5

Rate should be somewhere between 0.011>0.0145 depending on rod length/stiffness. Shorter rods maybe be as low as 0.011 and still be quite fast. Longer rods will require rates >0.135 in order to accommodate the mass of cane. Further, in my experience, the rate shouldn't exceed 0.023 or less than 0.001/5"

Having said that, some years ago, I cast a 7' 6" rod that had a negative rate of change through the ferrule area and it cast just fine. No accounting for my taste. (Don Anderson)

I am glad to introduce my thoughts of Designing some of rod natures. Those are stress curve, rod deflection, bending angle.

Up until now, not a few people must have a little difficulty to understand what a stress curve exactly means.  Why a stress curve generally imply a type of rod actions, or nature of a rod flexure.

I found its answer around Christmas days, oh God. (though I'm a Buddhist in mind.)

As stated in my last post, a rod deflection, or a rod flexure, can be looked in detail as the  aggregate of bend angles of each 1" section. When the most bottom (butt side) 1" section bends 1 degree, and when the next 1" section bends 1 degree, the second section is looked as bent 2 degrees from the rod axis (from center line).  Like this, by accumulating the bend angles of each 1" section towards tip top, we can get the section angle of the n-th section from rod axis, and finally we get the bend angle of tip top as the total (and accumulation) of entire 1" sections.  Thus we have the tangent angle of the most tip top. Since this is the fact and truth of mathematics and physics, this rule is really true.  So I can say, tip top tangent angle has some meaning!

Then, try to plot the bend angle of each 1" section (not accumulated angle) along with its rod point in inch.  The  resulted plot will show a kind of curve which we looked at somewhere. That is stress curve!  Not exactly the same to stress values but up and down exactly matches to up and down of stress curve. Since the math in physics are just tweaking the related things by using also related formula, it happens.  Thus we can have a cousin of stress curve which is shown by bend angle.  I named this cousin as "Action Genome".

Since the bend angle is the component of a rod deflection, we can manipulate both of rod deflection and bend angles as the target of designing a rod. And we can manipulate the bend angles by watching how the entire rod would bend, deflect or flex on the same surface at the same time, as a physical relationship.

The words can only convey a part of the whole. If you trust me or you want to verify this thought, please download the following excel file and try it out.  Look into "how to use" worksheet within the excel file for further explanation.  The file is free!

By this, most of you may have clearer understanding on what stress curve means. The stress curve does not only shows the distribution of stress values but implies that how the rod portion would bend.

The downloaded file is zipped.  After download, you just click the name of the file (DeflectionDesigner.EXE), the file is automatically unzipped and you are prompted where to install.  After it is unzipped, you have the excel file name, DeflectionDesigner.xls.  Click the xls file name to start the excel program. When starting up excel, another prompt appears if you activate "MACRO" or not.   Just reply as "Activate Macro". The excel file is made under MS Excel  of MS Office 2000 professional Japanese version.  But the contents were written all in English. I just wonder if Japanese version works in other countries...

I hope this would make any of progress in rod design!  (Max Satoh)

I think I understand you but, when you speak of Stress Curves, just exactly what do you mean?  (Bob Norwood)

Very good question it is.

I dare not to have said about this since the meaning (or handling) of stress curve may vary when we consider the stress curve in dynamic math.

But the compatible meaning of stress curve is the distribution of stress along with the entire rod length.

In static environment, Garrison's stress curve has a meaning of stress distribution (in a static manner) and an implication of relative amount for the depth of bend angle at that point, as a higher stress portion would bend more than a lower stress portion. Because of static nature, we can draw such a designed curve like 220,000 oz/sqin at point 5 and 130,000 oz/sqin at butt for a progressive rod.

In dynamic math, stress curve will turn counter clock wise than Garrison's one because the bent section will reduce its effective length, and as the result, moment will vary (reduced) and finally stress value will vary (reduced).  This will happen the more on the more flexed  rod.

So in dynamic math, it becomes Harder to utilize  stress curve as a design aid which implies the relative amount of bend like Garrison showed us.  It is not changed actually that a higher stress part would bend more than a lower stress part, relatively, even if it is used in dynamic environment.  (Max Satoh)

If some out there downloaded the file and successfully tried out, please let me know if it works fine or not either of on or off list, please.  (Max Satoh)

I downloaded your program and only briefly tried it.  I got no errors.  It will take some time to read your instructions and begin to understand how to use it efficiently, but at first glance, your program seems to provide a visual representation of rod behavior easier to comprehend than a static stress curve.  I think form most people it is difficult to look at a static stress curve and deduce that the tip of a rod will actually be nearly straight.  Your graphs make this obvious.  Your General Genome forms: Progressive, Flat, and Parabolic, provide further visual insight into actual rod behavior that everyone  has talked about but few have fully or partially understood.  I will report again after further study.  (Al Baldauski)

Thank you for the fine explanation.  I think your ideas are as clear and understandable as any I have heard.  THANK YOU!  for sharing.  I will download the spreadsheet and give it a try as soon as I can.   (Harry Boyd)

You are correct that the statically calculated bending stress using Garrison will be less when the rod is deformed dynamically because of rod shortening. One also needs to be aware of and consider the combined stresses under dynamic loading that include combined bending, shear, inertial, etc. that occur when casting a deformed rod. It is not a simple analysis problem. So, it is not clear that the combined dynamic stress at any point in the rod is less than the statically calculated bending stress considered by Garrison.  Garrisons overall approach was to "superload" the rod to compensate for the dynamic issue by using his "fudge factor" applied to the static bending stress model.  (Frank Paul)

So, it is not clear that the combined dynamic stress at any point in the rod is less than the statically calculated bending stress considered by Garrison.

I am not saying that way.  Shortening effective length just happens at the deformed part of the rod, I mentioned.  As the result, butt side would tend to have higher stress values "relatively" than static stress curve. So it is like, a static stress curve turns counter clock wise, (tip low butt high.)

Garrisons overall approach was to "superload" the rod to compensate for the dynamic issue by using his "fudge factor" applied to the static bending stress model.

I do not know well  about Garrison's  "fudge factor" (tip factor). It is difficult to understand why it was needed. Just a guess, it could be for an additional "force of inertia" caused by extended fly line when a rod turns to forward cast from  backward cast as it is applied onto the tip top.

I think myself is following the design approach of Garrison, I mean I am going to implement similar modeling of action  genome curve since dynamic stress curve becomes more complex than Garrison's.  If someone insist to want to use stress curve even in dynamic math, that'll be fine too.

But design criteria of stress curve must vary like this.  Make the stress curve nealy flat so that entire rod would deformed evenly under the dynamic deformation.  A little higher stress on butt would make parabolic type action and a little lower stress than flat line (around 140000 oz/sqin) on tip would make tip action type rod.  Tip stress must become lower than other part since it should be flexed.

Garrison was really great since he realized the stress curve model first, anyway.

Shear stress could be neglected in rod design, I guess.  It mainly happens at the top of the grip (thumb part), very fat part of the rod.  (Max Satoh)

I don't want to pick on anyone.  But the use of the term "dynamic" simply to distinguish the analysis of a deflected rod from Garrison-type analysis is not strictly correct.  Dynamic analysis of stress is verrrrry complex.  Most deflection analyses are still static or pseudo-static.  (Jim Utzerath)

Yes, I agree with you on that the really dynamic, or really natural analysis including all and entire physical phenomena, such as wind, density of air, shear force, dumping factor, etc., etc., is very very complex. But I do not think all is necessary for rod design. We may be able to clevery omit some those.

You can call so far analysis as pseudo, dynamic-like, fake or something else.  I do not care about it.

Please tell me when do you think REALLY natural analysis comes out and who does it?  Do you think it would work on PC instead of using NASA's mainframe computer?

Until now from Garrison invented his model, we are accepting the very limited analysis and it has been successful to make bamboo rods.

I think it is rather important to step out even if it is a small step forward.

Thank you for your opinion.  (Max Satoh)

P.S.  You should not understand the deflection tool is the dynamic tool.  It is only the tool to be used to define the desired deflection.  It is not any analysis but just the fact between deflection and bending. My another tool will follow to receive the designed deflection and calculate pseudo dynamic moment, stress, and dimension.  That is my dynamic tool, and it will continue a tremendous iteration of recursive calculation up to the limit of PC power.

Don't misunderstand.  I was only pointing out that "dynamic" is a very specific term.  I think that static or pseudo-static analysis is the best we can do now.  Perhaps some graduate student somewhere has written a research paper on wave propagation (See p 236 of Carmichael's book about Garrison), loop formation, or casting mechanics.  Air resistance, damping, etc. are probably lesser effects that may never be scrutinized.  I think, though, that a modern PC could readily simulate these effects if we could adequately express the physics.

I am not convinced that we could benefit much from the results of such advanced analysis if it were available, not having exhausted the potential of present experimental or mathematical methods.

Can anyone define what the Holy Grail is?  Is it distance, versatility, control, comfort?  (Jim Utzerath)

Could you define dynamic?  Isn't it the continuity of static state?  Your convergence spread sheet was also the continuous change from one state to another. If you call it pseudo-static, that'll be fine.  Dynamic is always pseudo-static.

Holy Grail of rod design in this context is the attitude which seeks more practical way than existing method.  There may appear another Holy Grail when a new method is overcome by fur better one in future too.  (Max Satoh)

In engineering mechanics, the term static, when applied to any object, means that the resultant of all forces and moments on the object is zero; otherwise, the object is undergoing some form of acceleration or change in shape. 

One of the assumptions upon which the definition of the beam stress profile is based, is that the internal forces in any section of the beam (fly rod) are balanced; IE: the forces of tension on one side are exactly balanced by the forces of compression on the other.  That produces the stress/moment relation that we have all been using.

In a dynamic system, the internal forces might be unbalanced and the stress/strain equation would not strictly valid.

Note that the G-loading that we use in rod stress is not really an acceleration, but a force, just as our weight is a force due to gravity.  Hope I haven't made it too confusing. (Jim Utzerath)

Thank you for teaching the definition in Physics. I understand that there is another strict world in defining the word in Physics.  Which seems be slightly different from the word in actual world.

Though I am not a physics man, I could make anyway a tool which is usable following some of the theories in physics.  Just forgive me in using the physics words wrongly as I was not a good student in physics class.

Then my word dynamic is the one in actual world, not in physics, isn't it?  (Max Satoh)

Help me to clear up my thinking here;  if we are not talking about an acceleration, but about a force, and if we are seeking graphic representation rather than absolute values, then we can still assume that, since F=ma, we are at least still dealing with a function of acceleration.  So the  relativity should  still be OK???  (Peter McKean)

When we speak of Garrisons 4G (or any other load) we are not adding a real acceleration to the model; but rather, as you said, we apply the equivalent force that such an acceleration would create.  A Garrison 4G load would be the same as hanging the rod and its  length of line out of a window on a planet with four times the earth's mass.  He then applied the laws of  statics to compute the stress. 

The Garrison model, as everyone in the list who has been following this these discussions should realize by now, constrained the rod not to deflect. This greatly simplified the calculation and in many ways made it easier to compare different tapers by taking the MOE out of consideration. (Jim Utzerath)

First I think we should do away with this "holy grail" thought. I think Max is is trying to come up with the next evolution in rod design, not the ultimate end all in rod design. Like the "HG" each of us will have our own concept of what that is, or means. I believe Max is trying not to comply only with the first half of Newton's first law of motion.

Jim, I would think that EG knew the rod would flex, deflect, but it was difficult in his day to comply with all the dynamic principles (math) involved with only a slide rule.

I think we all know that the casting motion is one of a gradual acceleration terminated  with a massive acceleration, and a stop (with a given amount of line (mass) and a given wind resistance). I'm not sure yet that even if Max is successful it will result in a more useful tool than G math, but it would certainly result in a better post analysis process. (how a given caster might flex a given rod). Knowing that, it will probably take years to comprehend how to apply this to rod design.

I also found Milward’s book interesting, but for a different reason, while attempting to debunk G math, he left you with nothing but rod design by modification. Not very inspiring. It is very interesting that using his tapers and G math you get the same action, as would be predicted by the taper. I never reached the point in his book that I understood how simply stating Garrison's assumptions were wrong made it so. If double hauling is the final test, then so be it.

I both agree and disagree with you Ralph, making rods for undiscriminating fishermen is what we do now. maybe looking to the future as well as the past will help all of us become more knowledgeable about rod design. As you said, as  Castaneda said,  "It is the bent of our nature". Some will try to advance the state of the art, others will do what they do.  (Jerry Foster)

In Max's defense, I was the one who implied he was searching for the Holy Grail of rod design in a message to him that I inadvertently sent off list. Not realizing this, Max perpetuated the thread.  I don't believe he thinks he is developing the Holy Grail but rather is advancing the rodmaking process to everyone's benefit.

I believe his use of the term "dynamic" applies to a static evaluation of the shape of a rod if a "snapshot" is taken during dynamic use.  He is evaluating a rod taking into account deflection rather than assuming it does not.  (Al Baldauski)

There in lies the crux of the matter.  Very few fly fishermen, will say that the greatest importance is distance.  I am not even sure how to quantify versatility and/or control.  But ah!! comfort? Why worry it to death?  If a guy likes the rod great, if not some other guy will. I don't denigrate what Max and others are doing.  After all What turns you on you do, but I see little practicality in it for most of the fly fishers today.  (Ralph Moon)

Statics and Dynamics are words used to describe the Mechanics of physical devices - space craft, automobiles, and fly rods for example.  Newton was the guy that set the basis for use of these words.  Newton wrote that:

Summation of all Forces =  Mass x  Acceleration ;      This is Dynamics

(Well he really said:   Summation of all Forces  = Mass x Rate of Change of Velocity where Rate of Change of Velocity = Acceleration)

Summation of all Forces  =   Mass x  0  =  0 ;   This is Statics

Statics is a subset of Dynamics when the Acceleration of the device is zero.  The device can be moving with constant velocity when looking at Statics.  I think it is important for an appropriate discussion on this list to use terms correctly based on Mechanics.  Jim's comment about Dynamics as being very very complex is correct.  Max, your  term of "Pseudo-Static" confuses me and I do not know how to address the discussion related to this term.  Could you please put your thoughts in terms of the above definitions which I think all educated and trained engineers and scientists can agree on. That will help all of us communicating on this list. I am sure our translation and understanding in language    from   Japanese    to   English    (and vice-versa) is an issue.  I am only writing this to improve our "international communication," not for criticism to anyone on the list.  Just my opinion. Max, thanks for sending me your XL file. I will look at it later today. I have been busy getting ready to teach an academic course on Dynamic Systems this spring semester at Clemson University.  (Frank Paul)

A very precise set of definitions.  To assist the discussion and I think in support of what Max is saying can I suggest another term that is in common engineering use, in the UK anyway.

The term is "static equivalent load" and is used in a static calculation to represent the effect of a dynamic load.  A good example would be Jim's description of Garrisons use of the multiplier 4 applied to the calculated weights to represent the actual dynamic load.

I may be wrong but I think Max's term "Pseudo static" is referring to the same thing.  Another example would be in a dynamic analysis such as a seismic model where the output may be in accelerations varying in magnitude and direction, the structural engineer will take the the largest values in several directions and apply these as "static equivalent loads" to design the structural elements.

To try and produce an accurate dynamic model of the whole system of line rod and caster might make an interesting thesis (Dyna3D?) but for me and I'm sure many others it would not actually help a lot.  Even if the estimated static equivalent load is not quite right its only effect will be to produce a rod designed for the wrong line weight.  Judging by the results Garrison was not far off using 4 as a multiplier.

The ideas Max is developing are potentially very useful and I look forward to his next stage.  (Gary Marshall)

After writing the last input to this discussion, I realized that "static equivalent load" is a term used by Civil Engineers to represent a dynamic load on a static math model. Since Garrison was a Civil Engineer by education, he found using that approach acceptable. Thus his "tip factor" in his design model. I am a Mechanical Engineer and one must be careful with this approach. It usually works very well for classic structural design, but in situations such as earth quakes it is not a good approach. A classic example of this problem was the Tacoma Narrows Bridge design in Washington State that dynamically blew apart because of high wind gusts that caused aerodynamic instability. I believe I remember from seeing the classic movie on the bridge, that this static equivalent load approach was used when designing that bridge. Anyway, I understand a little better Max and your communications.

I have reviewed Max's program and am going to put together some information that shows the relationship he is trying to demonstrate with his approach.  I am into the Strength of Materials textbooks to look at this approach.  (Frank Paul)

Yes I first  saw that  video about 30 years ago, very impressive.  Fortunately our rods are not susceptible to such problems, or not so that you would notice.

I think even the Civil Engineers use slightly more sophisticated methods these days but first order design has to start somewhere, dynamic models are fine for analysis but make cumbersome design tools.

Anyway what do I care, dumped it all to become a rod maker after all!

I am impressed with Max's work because it is visual.  When I look at a hypothetical stress curve I visualize bending relating high stresses to high curvature.  Even without the design bolt on the present tool offers the possibility to mimic the form of a stress curve on the deflection angle plot and then see the expected rod deflection, cool.

It is also potentially a great communication tool, I find it quite difficult discussing required rod actions with clients as they are considerably less clear than we are and look how much we can argue things about.  However most anglers can recognize the sort of bend form they like or at least think they like!  (Gary Marshall)

The bracket and enhanced stuff below is what I sent before.  Gary has suggested the words - Static Equivalent Load.  My understanding is this might mean the following.

The basic Dynamic equation can be rewritten to look like:

Summation of All Forces - Mass x Acceleration = 0

Note, this looks like a Statics equation because of the equals  0 .  It is called D'Alembert's Formulation of Newton's First Law of Motion. One needs to be very careful in its application as it requires what we call Free Body Force Diagrams that include the  Mass x Acceleration  term and must be placed correctly on the Free Body Diagram to get the correct mathematical results. It does reflect when done correctly a Statics mathematical formulation of the Dynamics problem, but it must be done correctly and carefully. It is easy to mess up unless one is very careful in the definitions of body motions and coordinate frames.  I have taught both forms in university level classes, and one needs to be very clear about how each is used. I usually use only the Newtonian formulation until students get the drift of how this second approach might work. The D'Alembert approach is very powerful, but it must be done correctly.

When I consider Garrison's modified Static Bending Model for stress, I think of his tip factors as taking into account additional loads  (line, rod mass, gravity, etc.) that do influence the rod deformations and apparent bending stress magnitudes and distribution.  I don't think about this approach as a Dynamic one.  Just my opinion.  Hope it helps.

{Statics and Dynamics are words used to describe the Mechanics of physical devices - space craft, automobiles, and fly rods for example.  Newton was the guy that set the basis for use of these words.  Newton wrote that:

Summation of all Forces =  Mass x  Acceleration ;       This is Dynamics

(Well he really said:   Summation of all Forces  = Mass x Rate of Change of Velocity where  Rate of Change of Velocity = Acceleration )

Summation of all Forces  =   Mass x  0  =  0 ;   This is Statics

Statics is a subset of Dynamics when the Acceleration of the device is zero.  The device can be moving with constant velocity when looking at Statics.  I think it is important for an appropriate discussion on this list to use terms  correctly based on Mechanics.}  (Frank Paul)

Nice to have all the physicists in discussion. I should say this first, I am not a physicist, merely old ex-loser of physics in young days.  I just caught up the knowledge of physics by myself by several books which are high school level, after making bamboo rod.

Thank you Frank for clarification, F=m x a, is the formula which I use through out the calculation of FORCE which is applied to a rod.

I apply both of accelerations, a and g, always.

a:  towards any direction, this is the acceleration generated by motion

g:  toward only direction vertical downward, this is gravity acceleration

A rod in my model, receives both of a and g type acceleration, always, even if the rod does not move, it is receiving g.  So the horizontally held rod would deflect a little even if it is not moved artificially. Optionally, when the design target is a boat fishing rod, as this rod is assumed not to be cast (moved), I only use g acceleration downward.

When a rod is moved, a and g is calculated according to the movement.

I have no confidence to utilize static and dynamic word in front of you.  But my understanding is, static and dynamic is the word applied to a model, to which we use our brain, not the mechanism nor method of calculation. If the model is assumed moving, I understand it is a dynamic model.  If the model does not move, the model is a static model.

My calculation is only follows the F=ma or F=mg, always. My calculation is made from one shot of time to the next shot of time to acquire the change of acceleration from time to time according to the movement. The change of acceleration is calculated like below;

a=(v2-v1)/(t2-t1)

: v is velocity, t is time, 1,2 are the time slice number.

Then consider a model which does not move basically, a rod not artificially moved, and fixed at the grip to a wall, this is apparently a static model  when it is not moved. But when a weight is hanged at the top of the rod, it starts moving "naturally".  Then this rod becomes a dynamic model by the weight at this moment. While the rod moves, time sliced view of the rod will show us that the rod is moving with increasing acceleration of g from a second (in small second) to next second. So this model is dynamic in my thought, if so calculated.

For Pseudo-static or Pseudo-dynamic words:

These words are used by myself to state about the model.  Remember the Garrison's rod model is static. Garrison multiplies 4 to the weight of

bamboo, ferrule, Line to Fish, and average of other parts. Let's consider of the weight first.

Newton defines as: 

Weight = mass x g (gravity acceleration),

g=9.8 m/secsec. (sorry for metric).

We can consider that Garrison multiplies 4 to the weight, or multiplies 4 to gravity acceleration.

Then 4 x weight = mass x 4g.

Mass x 4g can be considered as the object moves in a speed which receives 4G.  This is so called "equivalent to 4G". But this model does not calculate the change of  acceleration from  second  to    second.    So   I   called   this Pseudo-static, or Pseudo-dynamic because the rod could be assumed as moved by gravity, but no such effects are calculated.

This is all my thought and the source of wording.

It is very much appreciated if all the physicians could review my tool from the professional view point and correct it if error of physics application is found. Such cooperation will move this world to a good direction. (Max Satoh)

Let me try and explain how I see the approaches based on Mechanics and Strength of Materials. Hopefully I do not screw this up too badly in my thinking/writing and it provides some help  to listers and is not overly simplified. Ray Gould and others please correct me if I am off course.

What about Stress Analysis?

The Garrison taper design was based on Stress Analysis NOT Deflection Analysis. The following basic equation and assumptions were used.

Analysis Inputs:  Desired Stress Distribution; Material Weight/Density; Maximum Allowed Bending Stress; Tip Impact  (See the Book)

Maximum Bending Stress =  Moment of Load x HalfFlat Height /  Area Moment of Inertia ;

                S  =   M  c  /   I

Here c and I depend on the taper HalfFlat Height that is a very nonlinear function (cube roots - see Garrison Book) of geometry. This requires an iterative approach to compute the rod taper to match the Desired Stress Distribution based on changing taper dimensions.  Obviously, a variety of Desired Stress Distributions can be postulated, such as Linear, Parabolic, Semi-Parabolic, etc. as a basis for rod taper design.

It should be noted that the Modulus of Elasticity  E - a material property - is only used by Garrison to establish the Maximum Allowed Bending Stress for the assumed rod stress distribution. E does not appear in the above equation. This means that the calculated stress along a rod is independent of the material used to make the rod - it only depends on the rod geometry (taper and dimensions) along the rod length. This makes the computations easier than for Deflection Analysis - see the next part.

What about Deflection Analysis?

The basic equation for linear deflection analysis is given as follows.

Moment = Modulus of Elasticity x Area Moment of Inertia / Radius of Curvature

M  =  E  I  /  R     where  

1/R  =  First Derivative of the Rod Slope = Change Angle / Change Rod Length

M  =  E I  ( Change Angle / Change Rod Length)

        or the     

Angle  =  INTEGRAL { ( M / E I ) Change Rod Length}

This mathematics is based on the integral calculus and is more complex to carry out without a  computer (which Garrison did not have - just a slide rule - A good reason to use the Stress approach for rod taper design BC  -  that is Before Computer).

What is important here is to see that the  Angle  of the rod curvature depends on the Modulus of Elasticity of the Material  (bamboo, carbon fiber, glass, etc.) and the Area Moment of Inertia (geometry and taper at a given location along the rod).  Thus designing with deflection analysis requires both material and geometric properties.  This is more difficult to compute unless one has a computer program such as Hexrod or RodDNA which we have today. 

It is my opinion that designing a rod using only rod angle changes may provide a starting point for rod taper design similar to what Garrison did with rod stress distribution, but will require iterative techniques to account for material properties and changing rod geometry.  (Frank Paul)

Have read with interest the discussion on rod design "holy Grail", "garrison and all his versions" and all the other thoughts that go to make up our attempts to design or evaluate bamboo fly rods.

But I for one would like to hear someone commit to paper what they would like a "good" rod to do !

There must be many, many feelings or thoughts on what a flyrod should do or feel like in a particular situation and I would like to hear some ones thoughts other than mine.  (Bob Norwood)

To me a good rod will cast short, medium and long. It will also present small dries with super delicacy and then switch to large streamers (weighted wooly buggers) without any problems. Anybody with a basic skill level should be able to cast the rod without much effort. Instead of the caster adjusting their timing, the rod adjusts to their stroke. A good rod will also cast a line weight below and above the recommended line.  (Jeff Fultz)

Well, I never thought I would find it on the first try, but there it is "the holy grail" or so he calls it. Actually I think I might use the same name if the rod would, put itself together, thread the line and leader and then tie the fly and lead me to the fish, congratulations Jeff.

But do you think you might give us a little hint of some of the rod's parameters without the taper ? maybe the length, line size, line type and what you mean by short, medium, and long and How should the rod perform during these casts ?

 I'm not a casting instructor so maybe I am not using the right terms for my descriptions, but I would like to hear from some makers who are instructors.

I like to fish for bass, so my wants tend to be for medium length maybe 8 foot medium heavy 6,7,8 weight rods that have a medium tip that will set the hook in a 6 pound largemouth and enough strength in the rod to play and land it in a medium amount of time. Would also like the rod to cast about 55-70 feet of line with only one back  cast and  present the fly with good accuracy and be light enough to use 3-4 hours.  (Bob Norwood)

The Rod I was referring to is an 8' 5/6 wt. 2 piece. Casting short means throwing a loop in just the leader, and long means 100+ feet. The taper is compound progressive and the action is medium fast. I was trying to design a rod that would act like a 2 wt. in close and a 9 wt. at long distance all with the same weight line. This characteristic is also what allows the rod to cast delicate small dries as easily as it casts heavy weighted streamers. I also had to make the tip stiff enough to not bounce or collapse when overpowered. To give you an idea (in Garrison's math) the highest stress in the rod is around 180,000 KPSI, has a .075 dia. tip and takes a #15 ferrule. 

My rod design method requires the use of Garrison's "static" math calculations with a little bit of trial & tweak.

When explaining basic rod design in my classes, I break down the process into three quantifiable steps.

1. Taper = How a rod bends (i.e.. Progressive, Compound P., Parabolic)  

2. Action = Where a rod bends (Fast, Medium, Slow)

3. Power = How much a rod deflects with a set load (an 8' 6 wt. rod should deflect 2.6 feet with ~160 grains attached)

Anyone can then design a rod by first deciding how and where they want it to bend, then by selecting stress figures, they can choose how much power to put into the rod and calculate (again using Garrison's simple algebraic formula) the diameters needed to give them what they want.  (Jeff Fultz)

Can you explain the Power portion of your formula a little more. IE How did you arrive at the 2.6 feet of deflection with an 8'6" rod figure?  (Jim Lowe)

Deflecting the rod by a third of it's length is an AFTMA standard for comparing rods under load. (Jeff Fultz)

What are:

* compound progressive rod tapers?

* progressive rod tapers?

Was watching the Perfect Rod thread and tend to agree, rod should cast short/long/various distances/different weights of flies. That is what fishing is about.  (Don Anderson)

I refer to linear tapers as progressive (consistent dimensional  changes)  and  compound  progressive   as semi-linear as they have non-consistent dimensional changes along the taper.

I'm not an engineer so these are just in my own terms.   (Jeff Fultz)

Both "progressive" and "compound" are fudge-words, like "parabolic."  Nobody knows exactly what is meant by them.  But "linear" does have a specific application.  The term would refer to a  steady and  proportionate increase  in cross-section, from tip to butt.  To some folks, this may imply "dry-fly" action, but it isn't necessarily so, as there are far too many other factors involved in a taper. Also, the least satisfactory taper of all is probably one that's absolutely linear -- that is, one that has a dead-straight rate of increase from tip to butt.  "Linear" rates of increase usually exist only over certain, limited areas within an overall taper, and because these may be managed in any number of ways (in combination with other changes), the term really doesn't describe any particular action.

"Progressive," to most folks, seems to imply an action that shares the stress-loads of casting fairly uniformly along the length of the rod -- with "sensitivity" seeming to increase at a uniform rate on down toward the tip, and perhaps best describing what is meant by a "dry-fly" action (another term that can only be used with quote marks).

"Compound" can only refer to a taper that is comprised of any number of changing  rates of diameter reduction.  That is, it's among our most meaningless of terms, because all tapers are actually compounded of such changes in one manner or another.  The term suggests nothing in describing how any given rod may "feel."

"Parabolic" is an utter misnomer, because that geometric shape bears no relation to the trajectory of tapers as they are   designed.   Nevertheless,  the  term  has  become more-or-less useful in common parlance, as it's used to set up a certain kind of distinction to the typical "dry-fly" taper.  The "parabolic" taper implies an action that's more responsive (to stronger casts) through its butt section, while the upper half of its tip will be somewhat stiffer ("loading" a bit farther down its shaft).  The term itself is bogus, but it does help to describe a certain kind of feel.

"Semi-parabolic" should mean "half-parabolic," but it really doesn't mean anything more than "maybe-sorta-kinda-remind you of parabolic."  (Bill Harms)

I've been reading this thread on "good rods" and find us all wrapped up in terminology rather than describing what a rod should feel like as you cast it under a specified condition. As a small stream rod, maybe maximum distance of 25 feet. What type of casts do you want to make and what characteristics does the rod have to have to accomplish them.

I am not a casting expert nor a certified casting instructor, but I'm sure many of you makers are. I would like to hear from you as to how you would verbally describe how a rod should perform under a specified condition and what it needs to be able to do to present the fly under those conditions ? Just in general terms, as an example, it should have a soft tip but not too soft to present the fly at 35 ft with a normal cast yet still have enough back bone to apply the force necessary to turn the fish away from danger areas. some thing like this for different fishing conditions. I think if I knew what type of rod performance was needed, I could design a better rod, I just don't know these things.  (Bob Norwood)

Agree with you 100%. We need some meaningful and commonly used terms to describe a taper. You're definitions come about as close as I've seen. One thing that could be added is the "hinge" or "droop in the butt" and could be defined as a drop in the taper for 5 or more inches. Of course, a drooped butt is usually called a parabolic.

On the linear thing. Garrison's tapers were nearly linear from 20" > butt. Just looked over a 212 and it is  nearly  linear. (Don Anderson)

Thanks for those definitions  of "progressive", "compound", "parabolic", etc.. As a technical guy I have not seen a good definition of any of these terms -  maybe close in Ray Gould's books. Anyway, thanks for your thoughts. I agree with them from a technical viewpoint.  (Frank Paul)

I think it should also be said that a specific type of taper also  produces a specific type of definable action. A progressive action is  one in which the rod bends progressively more from the tip to the  butt as increasing load is applied. If you are making a short cast, a  small force is needed, and only the tip bends. As load and force  increase the rod bends proportionally more toward the butt. This  makes a very easy task for the caster, who soon develops a feel for  how much power needs to be applied to make a specific cast. The  Garrison series is a good example of this kind of action. If you  chart his tapers, you will see that they are almost straight lines,  being slightly convex in the tip area.

A parabolic rod tends to start the same way, with a little force  needed to flex the tip. The stiff middle transfers bending into the  softer butt faster, however,  which requires more sensitivity on the  part of the caster when applying force. The caster has to shift gears  and start using a slower stroke to avoid overpowering the full  flexing butt. The upside to these tapers, is that they will cast for  tremendous distances, while being considerably lighter than the fast,  stiff taper progressive that would be required to make the same cast.

If I had to guess at the taper chart of Jeff's good rod, I would  think it was similar to Garrison. Slightly convex, more so in the  tip, perhaps with a bit steeper slope and a bit of a butt swell tossed in.

A beginner seeking to understand all this would do well to compare  the thickness charts of the Garrison series, the Young and Pezon Parabolics, and the classic Dickerson fast tapers like the 8014, and  the 8013. It  seems to me that this would make a great project for a  gathering,  presenting the written information, and having the rods  available to cast so that the differences could be felt.  (Tom Smithwick)

As a beginner, your last couple of sentences sound great.  I would love to be able to look at some charts for different "feeling" rods and then be able to cast them.  This would give me a much better understanding of taper design.  (Aaron Gaffney)

I also tried to guess what the Fultz Holy Grail rod taper might be. My idea was that the taper might be a Garrison progressive with a somewhat lighter progressive tip on a somewhat heavier progressive butt. Here is my guesstimate:

pt dia. thou.

0   75.0
5   80.0
10 100.0
15 115.0
20 130.0
25 145.0
30 160.0
35 175.0
40 195.0
45 220.0
50 240.0
55 255.0
60 265.0
65 275.0
70 285.0
75 300.0
80 315.0
85 325.0  (Doug Easton)

I not sure how to put this, but Jeff was nice enough to supply a little additional information on a rod he designed and said that he really liked but didn't want to give out the taper. I'm sure he worked long and hard on it and feels that it is very special, I can respect that and maybe we should just leave the taper where it is, although I have to admit I would like to look at it also. (Bob Norwood)

I agree with your thought.  HOWEVER, if any or all of us want to make a guess at the taper based on what Jeff DID tell us, why not?  It's still not his taper (or maybe it is) so what harm?  (Neil Savage)

Since I am a big fan of using Garrison's math to design rod tapers, I'd like to see if someone can take the known set of stresses that I provided in the graph and come up with the  taper (within 3 - 4 thousandths) Anyone should be able to do this with the known algebraic equations, but can someone do it using another  design method? I think this is similar to the question Jerry was asking a few weeks back.

If anyone gets close, I will publish the taper.  (Jeff Fultz)

I haven't been following this thread closely, but if you would send all the parameters listed in Garrison's taper inputs like stress curve numbers, line weight and casting length, guide weights,  rod length, grip length, etc, I and many other of us could fairly confidently generate for you a taper. Without all this info, it's a guessing game.  (Bill Fink)

Just for fun here are the parameters of the rod we have been talking about:

8' 0" - 2 piece - #6 DT (I personally like a #5 WF   better) - 40' of line - #14 ferrule (sorry about the earlier mistake). The rod is medium - fast  action. The highest tip stress is ~188,000 and the rod has a slight hinge in the butt below the ferrule but also has a swelled butt to stop that action.

Bill, the point was for this to be a guessing game. If I provided the stresses anyone could calculate the exact dimensions. Knowing what power and action the rod is should give you a starting point for figuring out the stresses involved.

Again, if anyone can guess the taper by any means with just the info provided and be within .004 at each 5" station, I will publish the taper.

It's not like this is the perfect rod for everyone or even a secret magic taper, it's just that I worked hard to first calculate the numbers and then run the rod through trials and adjustments before I found a nice rod that did what I wanted it to do. This is the process I have used to construct all of my Fultz rod tapers.  (Jeff Fultz)

Having seen and cast a few of Jeff's rods, I think I my be able to shed a little light on this "Holy Grail".  while the taper you propose might be accurate (I can't say for sure), I think the fact, that the flat to flat dimensions at each station, vary by anywhere from 12 to 40 thousandths, contributes to the progressive compound taper. I think we all might want to study this concept further.   (Mike Canazon)

That's what we call a "complex compound progressive taper"! These types of rod designs can only be created while under the influence of your choice of stimulant or in some of our cases...a combination of two or more!  (Jeff Fultz)

Let's not forget, one of the real advantages of  cane is that we can create rods that might not be good for everything but are really good for something.  If I need a 6’ 7 wt with a roll casting hinge to fish deer hair mice at night in small deep streams, I can make it.  I don't think the graphite factories can do that. It's interesting and valuable to talk about the "holy grail" of a good all-around rod, because we need to learn more about rod design, but if that's the only rod we end up making  it'll be  pretty boring.  (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)

Once again you  come to the rescue, first with the web interface for Hexrod and now with common sense.   You made a great point that makes  me feel  so much better - I was worrying too much about my inability to understand all that was being said about rod design and the perfect rod.   Now I can just go back to trying to make a good rod for the small mountain streams that I fish most of the time and a good rod for larger water and always keep my Driggs close at hand.  (Hal Manas)

Now I think we're getting to the meat of the matter. Rods should be designed for their intended use.

Tapers that are linear and have about the same change from station to station will cast readily both long & short and are forgiving to the caster.

Whereas, parabolic tapers are more distance casting rods and required finer timing.

For the bulk of my stream work, I use mostly a linear taper. I want/need/require to cast both short and long. ranging from 15>45' excluding leader. I did work up a taper that has a mild droop for fishing dries/dropper combos. It's a 8' 6 wt.  And for the lake fishing, where I'm generally casting long lines, I use a Para 15.

And for some reason, tapers I've plotted seem to jump all over the place in terms of rate of change from  station to station. I've often wondered what the builder was contemplating.  (Don Anderson)

I like your comments on linear tapers, but one must have a good understanding of what the linear values should  be for each line size. For example, Garrison's tapers are after the first 15 inches from the tip mostly a linear taper except that the rate of change is too small for the rod line size. This is why most people say that a Garrison taper doesn't have enough back bone. If you would increase each station by .001, it will make the rod much stronger. The .001 increase is an approximate and I would really have to look at each rod to give a more accurate value. But your point of linear tapers being good rods and very forgiving is right on.

What I was really trying to get is a response from all the casting instructors as to what they look for in evaluating a rod. They are the experts and might be able to verbally describe what they look for in a rod.

I can design a rod if I know what the user is looking for and they can describe it in just common every day terms. I just don't have enough experience in casting rods in a large variety of situations.  (Bob Norwood)

I've noticed the same thing and it really doesn't  make sense to me that this was the designer's intent.  It seems far more  likely to be the result of original  construction error, measurement error,  varnish thickness error, on and on and on.

What's the consensus out there?  Are these  curves the results of various errors or my lack of understanding?  (Ed Berg)

I think it is a combination of factors. As I have stated before, there is no doubt in my mind that some of the tapers out there have errors.

The Hexy app I use does plot rate of change, and the typical taper does jump all over the place. However, we need to look at all of the factors. A .005 change between two tip stations is a large percentage of change. In addition, our graphs are compressed. If the graph is stretched, the jumps become much less "visual," just the way they appear in a rod. One person's "jump all over the place" might well be another's compound taper.  As an example, we have the Payne 98 taper measured on an original unvarnished rod by someone whose measurements I have absolute confidence in. It just happens to be one of those rods that jump all over the place, and that taper has made every "top ten" list we have put together over the years.

In fact, I believe that I first used the term "Holy Grail", and it was not in reference to a perfect rod. To my way of thinking, the Holy Grail would be the ability to look at one of those large rates of change, and predict accurately what would happen if it were not there, or, if it were increased in amplitude or duration. For example, I have a (theoretical) rod that casts perfectly in my opinion. Looking at the graph, it happens to be one of those tapers that have any number of large rates of change. Without building half a dozen rods, what would happen to that rod in my hand if those rates of change were increased or decreased.

We have access to any number of "clean" published tapers that can be examined, and one can draw one's own conclusions. Errors notwithstanding, I think it's in the eye of the beholder.  (Larry Blan)

Do we dare suppose that these strange taper configurations might be the results of makers trying to improve on a straight stick? just a thought.  (John Channer)

It looks like we are all in basic agreement on the definition of static and dynamic and are explaining it in different ways.

I personally use the term, pseudo-static, to describe a system which is, in fact, dynamic but is analyzed using methods of statics.  One example that comes to mind is the excellent illustration in Bob Millward's book in which he computes the stress from a photograph of a fly rod flexed at the beginning of the forward cast.

Incidentally, I seem to recall that the equivalent load in Bob's example is well over the Garrison 4G load.  But I think Bob said that the photo was taken during a "hard" cast.  (Jim Utzerath)

In the past several years I became interested in building bamboo flyrods. I have fished primarily cane for over 50 years. I decided to take a pause in my artist studio to find out ( in part) what intrigues talented people to commit to what is often considered an arcane craft.

Needless to say the search was fascinating, looking for the various tools, sorting through the guides, etc. along with the culms of bamboo. Enter the wrappers, adjustable bars, cutting machines, gismos and gadgets books, lathes and a mill, all new to me a novice rod maker.

Some of you know me through the chat rooms, others know me through the The Rodmakers , and through phone calls I have initiated. I have visited some of the of you in search of new ideas and guidance.

My production to date is 18 rods. And when I give a rod away, I feel empty, its the same feeling I experience when I move a painting. I'm sure many members of this list have similar experience.

In the past few months I have been the subject of an article The Art of the Bamboo Fly Rod in The Virginia Sportsman, also a featured painting in a North Carolina magazine. As the writer said the right side of the brain balances the left. Painting (for me) is about creativity and intuition, making a rod, as J.W. (Jerry Wall) explains, "it's really about consistency".

With the above quote in mind I realize I am not understanding the numbers. I don't understand to what extent changes occur after altering the marks on a computer DNA program. If one takes off or adds 5 or 12 thousand how much will that effect the action. What does smoothing out the sharp divides do for the action in actual casting. Excluding the other variables how does one learn how adjustments change the action of a rod by speeding or retarding the thrust of the rod.  I do understand that the numbers should be brought in as close as possible to make the tapers of the rod dimensions consistent. Thanks to JW and Jerry Foster who have refined the way of working with numbers with a CNC computer coupled to a tapering machine. We mostly used our 5" adjustable bars to accomplish our desired tapers. With the advent of the CNC tapering machine one can adjust the tapers in fractions of an inch. This capability of super fine adjustments greatly increases the need to be skilled in reading and understanding the numbers. Even though I work with the standard 5" spaced bars the freedom of creating tapers based on solid numbers would me well. The CNC machine shows what is capable and creates a benchmark The machine is not a revolution, it refines the process which benefit all of us. Whether one uses the bars or the CNC both require a understanding of the numbers.

Could we rodmakers have a dialog on the handling of numbers.  (Richard Kevorkian)

Sounds like you have wandered upon the $64K question for many of us.  I can't comment much on the CNC programs since my only experience is reading the Power Fibers article.  The answers to your questions below are largely, "It depends....".  Obviously adding or subtracting a few thousandths of an inch just above the cork will not have nearly as great as doing so in the tip-most 10-12 inches of the rod.  Smoothing out the sharp divides can also have major or minor effects.

There are several ways to learn what the numbers mean.  You can chart and graph some tapers and begin to study their general appearances.  You can study the information in Garrison and other places concerning stress curves.  You might make a chart showing each of the 18 rods you have made and compare their dimensions with your casting experiences.  You can cast every bamboo rod w/in a few hundred miles of home and compare your tactile sensations with the taper and stress graphs.  You can study the long discussion we had on this List early in 2006 and glean much useful information there.  Pay particular attention to the thoughts of Max Satoh, Jerry Foster, Bob Norwood, and some others.  And apparently with the new CNC machines, you could choose a taper as a baseline and make several different variations of it to learn what happens when you add a little here, or smooth out this bump there.

I can tell you what I do.... I pay close attention to the different rods I cast and compare their tapers.  I make a few modifications in attempts to make them fit my personal likes and dislikes.  And once in awhile I come up with something I really like.  (Harry Boyd)

I realize there are many rodmakers who are very comfortable using the brilliant tapers from the older masters, or for that matter contemporary masters. When I began reading books and learning the process I always had it in mind to jump off using a taper of my own design. It was a passing thought. I remember the late Harmon Henkin in the late 70's asked the late Russ Peak about loading up a stiff center in a glass rod so the effect would function as a fulcrum creating a firm parabolic action. I asked Mr. Peak about it and it was, not in his words, a total disaster.

My concerns are how to move further away from what is, to what is possible. I have a beautiful Chris McDowell 7' 6". He worked between tapers of two past rod makers and developed a rod which is a delight to use. His help is invaluable to me.

If .0006 would move a rod from one line lighter or heavier would it be fair to say .0006 percent from or added to each will make a substantive line change. Taking into account the addition or subtraction of a tip would be more drastic than off the mid section.

If others have beliefs which would help me and many other rod builders pursue the numbers it would be a revelation. Harry, not up to your standards.  (Richard Kevorkian)

You're on the right track.  Adding or subtracting a small percentage to each station will likely produce a more accurate change than an arbitrary factor of, say, .006".  Better yet are the suggestions to use either Hexrod or Rod DNA to make the changes for you.

Some of the ideas of taper manipulation are still more art than science -- at least to me.  For example, The PHY Perfectionist and Wayne Cattanach's 7' #4 often called the Sir D Special are quite adaptable tapers.  Dickerson two piece tapers seem to thrive when making small adjustments to account for building  hollow.  Other tapers don't adapt well.  For instance, the 8' 3 weight Leonard Tournament listed on Jerry's Rodmakers page doesn't seem to translate well into other lengths or line weights.

I seem to remember that you have several (eighteen?) rods under your belt.  That's about the point many of us start trying to refine our rods to make them fit our needs.  The only way to know for sure what your taper manipulations will do is build the rod.  I've got my share of failures under my belt that are part of the steep learning curve.  But they sure are fun!  (Harry Boyd)

I think a lot of it is it gives people the chance to justify and enjoy being what in any other field would be considered excessively fussy.  (Tony Young)

It's a lot of work, each of us has to come to their own conclusions.

There are lot of makers out there that can look at the numbers or a taper graph and tell you a lot about the rod. I have to rely on stress or deflection to give me a clue.

The key is to develop a feel for rods. I recommend casting with your eyes closed. Once you can feel the flex and the weight of the rod the numbers (stresses) will make more sense. You just have to do it over and over and over until you can feel (control) the line. I guess this includes loop control.

The ability of bamboo to transmit this feel is what should separate us from the graphites. The separation between the two is to be able to cast by feel, rather than timing.

As Dr. Weiss reminded me it is all about the caster. However, like golf clubs, or baseball bats, each may have a range that we find more enjoyable.

Consistency and repeatability come with process. Each time we change some aspect of our process we can effect the final result.

It might also be helpful to break the rod design into tips, mids, and butts, and how each part of the rod effects the line and fishability.

I look at each rod I make as a specially designed tool. For-instance, a rod that you want to roll-cast well will probably have a hinge (maybe in the but section). Theoretically this should weaken the butt and this rod should not cast as far as the same rod built without the hinge. Or, at distance you may not be able to control the loop as well and this could effect the delicacy of presentation.

Maybe everyone can take a shot at what part of the rod controls what?

When you say thrust, can I interpret that as timing? Or do you mean  power?

Regarding bumps. I think Tom Falk recently commented on the concept of "Fair".  I think that is probably the  best single word to summarize what I would like to see in my designs. smoothness of  change should equate to smoothness of power transition (flow). (??) There are a billion great designs out there, most will cast just fine, but the one with all the zigs and zags will not cast as efficiently (user friendly) as the one without. It's a matter of how  much power you have to put into the cast to achieve the same results.

I guess it is generally accepted that the rate of change of the taper is a key to it's speed, fast, medium, slow. I 'm never sure when someone else says a rod is fast if they mean it throws tight loops or you have to move your arm more quickly or it recovers quickly.

A .006 increase in dimension is generally considered a 1 line wt. change. As Harry pointed out  this  may  be  .001  in  the  tip, and .012 in the butt. It appears the butt has to increase proportionately more to carry the additional stress of more weight in rest of the rod.

OK, Stresses.. There have been several good treatises written on stress curves so this will probably be heavily plagiarized.

I look at stress curves from an inverse perspective.. (these are my views and are not necessarily scientifically correct)

The higher the stress numbers the greater the deflection. Rod tips usually reflect big stress numbers 200,000 to 350,000 in oz sq. This part of the rod obviously flexes (deflects) the most. From an internal perspective,(inside the rod) these high numbers represent the inability to absorb a load. Or they shed to load down the rod toward the butt.

The rod undergoes stress for three reasons. A force is applied by the angler, the weight of the line, and the weight of the rod and it's components.

The casting force is normally applied at the handle. The rod is therefore stressed from the butt to the tip, thence onward to the line and the fly. The line is a resistive load and adds to the rods natural resistance to change (this is not correct, but I am searching for a better way to express it). More stress. This is the reason that you must either know or discern how much line, of what weight, is used to generate a stress graph. Each rod is a tuned weapon. Most  rods have a wide angle lens, they will work well over a large range of distances and line weights. But here is always one distance that is most pleasing.

To digress, I think it is very important for each person to learn which stress range they find is the most comfortable. This has a lot to do with each persons casting motion, the power they like to apply and when. Garrison used 4G's as his power factor, this is in a static mode, you may use more or less. Also the better casters slowly accelerate the rod during a cast so the flow of the stress within the  rod is a factor which can make the line twitch and undulate.(bumps).  In my case it is usually not the rod that causes these formations but my casting motion. If you want to flyfish, you must learn to cast. If you want to understand stress you must learn to feel the rod. (back to paragraph 3).

The numbers, when interpreted by stress analysis, show the speed of the rod (slope), the type of rod (para,etc.) and the range the rod was designed to cast within.

Use Larry's RodDNA or go to Frank's page and plug in a lot of different parameters. You will begin to see how different line lengths and wts effect the range of the curve. (Harry's thought)

Find out what range the rods you like fall into. If designing from scratch for someone else a lot can be discerned from the rods they like.

Mostly, it just takes time  and work to get a feel for stress curves, mostly.

Take a rod you like and go into the yard and cast it. Make note of the distance you like the rod the best at. Plug these numbers in. If you do this for a variety of rods I bet a pattern will emerge. Or you may like different rods for different reasons.

Sorry about the ramble...

Of course I'm wrong about a lot of this..so feel free to correct my misconceptions.  (Jerry Foster)

On the other hand maybe we can talk about what happens at the stop in  the fore and back cast.  (Jerry Foster)

That's a far shorter topic, although I think it is part of "doing the numbers", in the sense that the stops are where the rod is really put to work, where the numbers meet the real world. If the rod can be felt/observed during the stops, it is there that the effect of adding or subtracting from the taper will really show up.

Back when I was crashing trucks for a living, one of my responsibilities was running the crash films. I was always amazed at what a stainless steel antenna did when the truck hit the wall, and how easy it was to see with those high speed cameras. I've often wondered if a rod is going through any of the same gyrations as it loads and unloads.  (Larry Blan)

I take it from your post that you have the rod DNA  program, and hope that you have read Chris Bogart's articles in Power Fibers on how to use it. If so, you have the most powerful tool  ever devised to make it easy to understand tapers.

What I would suggest is that you narrow your focus, and look at several rods of different character that have the same line weight and length.

I would suggest 8 foot 6 weights, since there are many to choose from.

First, add a new taper to your collection, a straight line Powell B9 starting at .074, and ending at .362 at the 96" mark. Accept that this is a moderate to slightly fast taper 6 weight.

Now compare that to the Garrison 212, a moderate, slightly slow progressive. Look at the Cattanach 8 foot 6, an adaptation of the Para 15, a fairly extreme parabolic, and also the Dickerson 8014, a classic fast taper.

These rods are very different in character, which will be reflected in the wildly varying stress curves. Stress charts are instantly available in rod DNA, and can be superimposed for comparison with a mouse click. The ideal would be if you could cast the actual rods and  feel the differences.

Now look at the thickness charts and superimpose them. What you will find, is there is not huge variations in the numbers, and that the tapers cluster around the "standard" B9. Small thickness variations produce surprisingly different rod characteristics.

So what I am suggesting to you is that even though you feel confronted by a vast sea of meaningless numbers, for every line weight and length, we are actually dealing with a fairly narrow  range. The line weight of a rod is determined in the tip area. The tip has to be weak enough to be bent by the weight of that line, but strong enough to recover at casting speed. That's a narrow range. The butt has to have enough power to carry a fair amount of line in the  air, but not be so stiff that it does not bend at all. Again, that's a narrow range. The action of the rod is determined by what happens in between the butt area and the tip area. With rod DNA, you can quickly look at a variety of the various tapers, and get a feel for how they work. Some of the above is greatly simplified, but if you do the comparisons, I think it will help. As I have often said, however, until you cast the rods, you really don't know much. Try to get to a rodmakers gathering.

Hats off to the guys who worked on rod DNA, they did us all a favor.

For those interested in such things, Bill Harms and I will be doing a program on tapers at the Catskills next week. I'm going to do the taper 101 portion on the basics, and Bill will follow with Vince Marinaro's unique approach. We will have some of the various type  rods to cast.  (Tom Smithwick)

In addition to the theory and casting different rods with different line lengths you really could try to modify the rod: make an inside-out rod and shave the rod thinner to see what follows.  (Tapani Salmi)

How many of you who design your own taper incorporate a hinge 20 inches from the butt section  in a rod over 7ft?  (Gary Nicholson)

Do you mean the start of a swell? If yes then sometimes I do.  (Ken Paterson)

If you guys are talking about hinges, then swells are a different thing.  A hinge is an area of lesser dimensions, meant  to provide  a slight slinging action,  for roll  casting, etc.. A swelled butt is a cosmetic nuance which foreshortens a rods action.  Which is just the opposite of a hinge. Or maybe I just don't understand the question?  (Jerry Foster)

Jerry, no my question was regarding hinges NOT swell butt sections. Just was interested to hear comments regarding hinges on longer rods.  (Gary Nicholson)

Well in that case...The answer is... depends on the rod, if you have a longer rod that doesn't rollcast as you would like then a hinge will help. You might think of the hinge as the distance from the top of the handle rather than from the butt, as it is not a fixed distance. And because reelseats and handles my vary in length. Again, the placement of the hinge is dependent on the rods taper and the persons casting action. I think Wayne placed the hinge 11" from the top of the handle. However in discussions he said this was not a fixed distance and it might be better somewhere else. I put hinges, transition zones at various places along the rod to enhance certain a "feel" I am trying to incorporate in a rod. Indeed a longer rod is more adaptable to more transitions simply because it's length allows for more action. In a shorter rod a hinge will occupy more space proportional to the rods length. huh? Cane is a funny substance, it takes a change for a much longer distance than I originally thought to have any impact on the feel of the rod. I believe this is because of "general relativity".  Where generally as the rod deflects the changes in the rods taper at a specific point are averaged by the distance over which the rod is deflecting around that point.

I don't even know if this is an answer, but it's part of a discussion anyway.  (Jerry Foster)

... Where generally as the rod deflects, the changes in the rods taper at a specific point are averaged by the distance over which the rod is deflecting around that point. I don't even know if this is an answer, but it's part of a discussion anyway.

Jerry, I "generally" agree with you :-) , but during a cast, isn't the rod deflecting, to some degree along it entire length?  Except of course, at that instant when the rod is transitioning from the back cast to the forward cast?  So, expanding on your idea a bit further ...

as the rod deflects the changes in the rods taper at a specific point are averaged by the distance over which the rod is deflecting around that point.

... but that "DISTANCE over which the rod is deflecting" around a specific point, and subsequently averaged, is always changing depending on what point in the casting stroke the rod is at any particular instant.  In other words, that "distance" would be longer when the rod is fully loaded verses just before the rod is transitioning from a back cast to a forward cast.

But then again...maybe not!   :-)))))   (Mike Biondo)

Great.. yes indeed you are correct. If we look at a the rod at the start of a cast, as the rod is deflecting down the shaft, then a given transition point will have more effect as it is just beginning to deflect (the instantaneous deflection point). As soon as the rod deflects past this point the the "general" effect will take over. That's why short little changes in the taper have little effect on the feel of the rod. You notice Mr. Norwood showed a long hinge in his designs. Short little changes have the effect of  power leaks because in the general theory, the rod cannot react to a change in taper that is greater than it's ability to deflect around that point.

The transition zones I was speaking of were along the rods length (taper). more than the transition points of a casting stroke. However, when and how power is applied to the rod will certainly govern the timing of the the deflection of the rod.

Yes, a fully deflected rod is probably the average of the sum of all of it's individual deflection points. total deflection angle. That is the lever part of the rod and how it gets there is where we most "feel" (interpret) the rods action.

That's another reason I like Max's program. I gives a dynamic view of the deflection of the rod. Makes you think about tapers in an all new light, if you are inclined to do so. And by the way Mark, if you read this stuff..hee hee, Max gives the option of G code output also. Including header and trailer files of your own definition.  (Jerry Foster)

Yes, Jerry, that is pretty logical.  (Peter McKean)

Jerry Foster offers an elaboration of the 'hinge' theory ~ and this 'knuckle-head' still doesn't understand what it's about.  There is evidently a procedure for introducing a 'hinge' in the design of a given rod.  And there's been some reference made regarding where such a 'hinge' may be located, eg; a specific distance from a given point along the length of the rod.  What isnt clear to me is, what exactly is the characteristic of  the design of a 'hinge'?  Does the taper drop (increase) sharply, or is there a reduction in the amount of taper over a given distance? ie; a 'leveling' condition over a certain span?  Here's my dilemma:  While recently planning the design and construction of a 7', 2 piece rod, I elected to 'fiddle with' the taper specs of a Garrison 201E.  Inadvertently the tip section at the 25" to 30" stations shows a taper reduction of .006" in contrast with the other 5" stations having the usual incremental changes (.013" +/-).  Surprisingly the rod action seems to be unusually 'fast', with a 4 wgt. line.  My question is, is there a 'hinge' present here, and would such have a positive or negative effect?  Thanks for any enlightenment.  (Vince Brannick)

Take a look at the stress curves of the various Cattanach “Sir D” tapers in RodDNA or other online sources. Study the tapers and you’ll see what they look like.  (Larry Puckett)

The reasons I ask this is the shorter rod requires the angler to move rod a greater distance to achieve line speed in equivalent speed to the longer rod. Hence, the need for a hinge in the shorter rod length. The longer rod has a longer effective length and greater tip speed Designing fast action fly rods which cast distance. I noticed the rods performed very poorly when subjected to roll casting  switch casts and Spey casts. Yet softer more slower action rods  were  superior  at these tasks. It seams to suggest that a fast action rod if subjected to roll casting should incorporate a hinge.  (Gary Nicholson)

Fast taper carbon rods, of which I have a representative selection, do not, mercifully, have hinges. If they did they would not only be seriously compromised for the job they were designed for - casting great distances - but would feel utterly horrible. You do not employ a Ferrari Enzo for shopping purposes any more than you race a Range Rover. If you want a roll caster you slow the taper down, if you want a distance rod you speed it up. As it was in the beginning, is now, and ever shall be. It's the Physics I blame.  (Robin Haywood)

What a lovely post.

You begin with blasphemy

Resort to conjecture (Do any of us KNOW the formula for lightning rods)

Use an untrue analogy (the race mileage of Enzo's machines is far outweighed by their street mileage) (If I had a Ferrari, I would drive it everywhere, just not park in a parking lot) (I know this will annoy you, but one of my favorite cars was my Turbo'd JPS)

State the truth (however couched in an untruth, a hinge is not a door hinge, but a slow section of a rod)

Throw in some scripture (I would guess to anoint your point of view) (Or maybe just to balance the opening stanza)

And end with a irrelevant truism.

Your point was....I guess there is only one way to make a fly rod?   Ooops two ways, fast and slow.  (Jerry Foster)

In fact it was a good post. Graphite is supposed to be fast. It can be anything but then I suppose you could govern your old Turbo JPS. I took a spin in a BMW Z4 yesterday and great fun that it was unless you are shopping for a hamburger the boot of a range rover is much better for the groceries and the physics aways were and always will be constant and unchanging in this universe in any case.

I was waiting for something off colour from Robin but strange as it may seem it wasn't there. Sort of like waiting for a Benny Hill skit to become low puerile and all you get is high literature.  (Tony Young)

The post in question was no more inflammatory than some which have rased the temple in the past.

They do keep discovering bits of Physics which make it clear we have been generalising,too.

Its amazing the amount of shopping we can get into the MX5 (Miata), but one of the estate cars is much easier, especially the one with the opening rear window. I thought it was a weight and money wasting frill to support the exotic list prices of BMWs.

So don't listen to me on cars, all the Ferraris I ever drove would have won no races  which involved more than one lap, but I'm told they are now better, more like Fiats, so five laps then.

I don't mind slow bits in rod tapers, all mine have them, nearly invariably in the middle, its reverse tapers I object to, where any dimension is less than the one preceeding it, measuring from butt to tip, just to be converse. And, of course, you can make a fly rod with any damned taper you like!  It just depends on what you want it to do, but a cannon won't roll cast very well!  (Robin Haywood)

Good way to seek clarification. I still haven’t understood or been able to imagine how to add a hinge or what a hinge consists of. It would be nice to know the construction technique of a hinge before talking about where it can be put. I was about ready to start cutting notches in a butt section or thinning it with a pocket knife.  (Jerry Woods)

If you look at the Cattenach "Sir Darryl" in Hexrod, you'll see the slope of the taper drops off between 45-55" and the stress curve goes up there.  (Neil Savage)

Generally speaking it is a flat spot in the taper a range of 5" or 10"where the taper gets neither larger or smaller. this causes an increase in stresses at that location. you will observe such a taper in the archives called the "sir D" one might discuss the appropriatness of such a device but that is what everyone is talking about.  (Timothy Troester)

Just was interested to hear comments regarding hinges on longer rods

Could you not make the argument that any rod that fits the description of "parabolic" by definition hinges in front of the handle to one extent or another? That gives you a lot of successful tapers, most especially from Young and P & M to look at, many of which are on the longer side.  (Tom Smithwick)

Indeed Tom.  In fact the whole area from the Mid to the butt could be regarded as a long hinge.  (Jerry Foster)

So if an area of a hinge is smaller area or the opposite of a swell then no I don't do it and never would for a longer rod because in my opion it would put too much stress in that location where normally you'd want the most strength. Normally for longer rod I use them to target bigger fish.  (Ken Paterson)

Actually a swell places more stress on the rod than a slight hinge would. This is because all of the stress is placed on the area right in front of the swell. All a swell does is make a long rod shorter, in most cases it doesn't matter. But I haven't heard any of the swellers talk about incorporating the swell into the stress values.  (Jerry Foster)

Also I think you need to consider the whole rod. The stress level at the hinge is going to depend on the stress in the tip. If the tip section flexes deeply it foreshortens the rod reducing the stress at the hinge.  Sometimes a hinge isn't a hinge.   (Doug Easton)

Usually on my heaver rods say 6 wt -- 8 wt I will use a hinge starting from anywhere between 20 and 30 ". The hinge will usually lasts over a 20 to 25" length. It really depends on which rod I am working on and it's length. I have built some as small as 6' with a hinge, they are nice but fast 5 wt rods. The largest one I have built was a 8'10" with a Garrison tip and a 20" wide hinge in the butt ending with a butt swell which was large enough to stop the action before the handle.

Some might think that the hinge would slow the rod down and make it soft, not so my rods are very strong and throw a long line.

Hope this helps.  (Bob Norwood)

That’s great I was just wondering if a hinge on a longer rod would really give any advantages.

On a short rod I think it does.  (Gary Nicholson)

Thought I'd open Pandora's box again on rod design.  I am using RodDNA.  Do you folks try to duplicate the stress curves on rods you are making longer or do you pay more attention to RAV and LWV?  How about when changing line weights?  As an example, I tweaked a 7' 4 wt Garrison 201 to 8' 5 wt by using the stress curve.  I was able to approximate the curve(although the first 10 inches I intentionally lightened a little).  Overall the rods cast very similarly, but the longer rod seems to have a little less punch.  I wondered if more closely approximating the Garrison 212 would give a better feel?  In other words, if you want to make the rod longer or the line weight heavier, do you slightly decrease the stress curve to get a similar feel?  (Dave Kemp)

Yep,  make a rod longer and it looses some of that punch. Everything being equal, you get a lot more deflection for the same conditions before you lengthened toe rod. Take a look at the formulas for small deflection of a cantilever beam.

Fb = (FL^3)/(3EI) where

and I do not change, and keeping F constant it is easy to see what happens here. L is a cubed term so it has a large effect on deflection as the beam gets longer. Garrison eludes to this in the chapter on rod design in A Masters Guide although he does not specifically say so.

Enjoy the rod design journey.  (Jerry Drake)

Since E and I do not change for a given material you might as well use the time honoured..............

Deflection is proportional to wl3/d4.

Deflection is thus directly proportional to the weight applied to the tip but proportional to the cube of the length and inversely proportional to the fourth power of the diameter.

Unfortunately this does not really work in the real world and you get the results you mention in terms of actual feel.

Largely due to the effect of the weight of the added material, it pays to apply the crude but effective Gould measure of "Fastness" to the result. To do this apply the Gould formula but adjust it for length. If the length of your new design is, for instance, 10% longer than the original then add 10% to the 50'' that Gould uses, these being the 50'' from the 10'' station to the 60'' station. It’s a bit rule of thumb for some but it works well enough.

To further clarify I might add that what you do is restore the rate of taper as expressed by Gould to that of the rod you are modifying.

In other words id your 10'' station is .100 and your 60'' station is .250 then the difference is .150 which Gould says we should double (for some reason) to arrive at a Gould rating of 300. Gould thinks this is fast, I don't, by the way.

When you extend a rod this rating will decrease so you add a small percentage to each station to restore it. I do this by trial and error and, of course, you do it by adding a small percentage to the RATE OF TAPER between stations, not the dimensions at the stations themselves............

This was meant to be quick and easy, I see its not, again!  (Robin Haywood)

I would like to get a feel for how many really design their own tapers from scratch.. jump up now.. because there is no answer to your question. And it takes a conversation to drag out the infinite detail of what each of us thinks about each detail.

As a synopsis from my perspective.. Most will have some other methodology but this is the only I could my get my ears around even the basics. And I have more questions now than I had before as I proceed down this path.

First as a guideline: There is no rule for a good taper. This is going to be boring I can tell you already. 'Cause I'm just going to drag up the same stuff.

There are a couple of boundaries...Rods that are too soft.. a taper that everyone says "what a noodle." But I made one of those for one of my friends .  A slooow 2 wt and he thinks it's the most fun small hopper stream (streams you can hop over) rod he has. I really made it so it will collapse if you try to lay a haul on it.  But there is a limit.

And of course the broomstick. But yet again I made a broomstick and some gorilla jumped up and said, "Someone finally made a rod for me".

As I stated before no matter how good or how bad a caster someone is there is a rod out there that will fit their style. It may be one that has never been made, or never will, or a Young Perfectionist. So in order to design rods you have to go beyond the whats in the taper and also consider the target. Not the fish but the fisherman (including ladies).

While I'm sitting here trying to compose this I realize I almost don't have the knowledge to continue.. But I will try..

The best taper is one that fits a persons natural stroke. I think most, and especially better casters have what I call a natural and and adaptive stroke. The natural one is easy, you watch, someone picks up a rod and starts laying out line. The whole process is easy and natural, and they smile. That's the rod. The rod likes them. Then, especially with beginners and bad casters, they struggle to get line out and fight the rod, you can see it as a bystander. The rod doesn't like them. There is a rod that does though, no matter how bad they are, it's up to us to find it. And there are the pro's, they pick up a rod and take 3 or 4 swipes and then start putting it through it's paces. These are the good athletes, not only are they finding the rods parameters but they are letting there mind and body adapt to the rod.. hence the name. They may never like the rod, or they may end up saying that's a sweetheart, but it is not the rod they love.. the natural one. So my message at this stage is there are no bad rods.

The other side of that is when someone pops up here or over and Clark's and says I want to make (buy) my first bamboo rod, what should I make? 36 people start arguing about which taper they should make first. I had an advantage there. Wayne decided. Now on this list I see few ulterior motives, people are honestly stating the rod they like...I don't get into those things because I have no idea what kind of rod they need. On Clarks, if it's one of the collectors responding, duck, there may be a little price pimping going on. No disrespect intended, I have found that a guy like Dan Brock knows more about rods and tackle  that I ever want to know.. And what a joy to talk to..

My first shot would be. Understand stress curves. To design rods you must have some other means than just make a rod, cast it throw it away and go make more changes on a dimension graph. We been through the planing bar thing, I will not go back there. But the mill has set me free. Without it, I just wouldn't have the time to do outrageous things to tapers. But it's all engineered. None of it is happenstance.

Back to the same story....  If you want to understand stress curves. YOU MUST DO THIS OR I WON'T CONTINUE. Take your favorite rod and a tape measure out to the street, backyard tomorrow morning. Cast it, find the sweet spot. That is the middle of the range that feels good. not the longest or the shortest distance.

YOU MUST DO THIS..

When you find the sweet spot, lay the rod down and measure the line out past the tip top. Go back to the shop, house..don't leave your rod laying in the street please. Pull up you favorite stress curve program...Larry's, Frank's, Bob's.... and put that distance you measured in the line to cast slot. <If your rod isn't already there you are either way beyond me or you need to catch up. Measure the rod and put it in.>

Now hit the calculate button. NOW you have a rod that is stressed at it's sweet spot. No matter what line wt. it is you now have a place to start comparing and evaluating rods. Without this you can/will flounder around forever. I will continue more if anyone is still interested but you must start here. If you can't see where I am going there is no point in going there.

This is not I tell you what makes a good taper, this is the toolbox to do it yourself. If you don't want to put in a little thought after all these years, I will not waste my, your time.

GET OFF YOUR BUTT  AND GO FIND THAT DISTANCE!  (Jerry Foster)

This sounds real educational. I'm in. My yard isn't all that much bigger than  this, but  my current  favorite, a Bolin ST-4 with a WF-4 line, starts felling good with a relaxed stroke at about 35 feet and my crappy casting falls apart at about 45. I normally plot a 4-weight at 40 feet... just because David said he does it that way.  (Larry Lohkamp)

I already received a great question about "natural stroke" It doesn't matter, you don't have to evaluate it or know what it is. (for this part of the exercise) It's the way your body wants to cast. It can be enhanced through training to make it more efficient. And you can think about it a study it yourself. Or go get casting instructions. It's how you push, pull, your hand wrist, elbow,  shoulder,  whole  body. It is also the length of your bones..forearm, upper-arm, etc. They are the levers along with you own unique musculature, that make you move your body the way you do. It is unique to each one of us.There is no universal body, there is no universal rod. Sorry. Some of the experts can join in here later and enhance this..casting styles and there faults. It is important though because how you do it is how you apply "the force". And that changes the way the rod works.

OK, The reason I asked you to use your favorite rod should be obvious. The shape you naturally like is already there. More about shape in a minute.

But You now have a rod that is stressed in the zone that that rod likes to work in (FOR YOU) That is the critical point, for you, not for anyone else.  Stress, whether you want to piss about if Mr. Garrison had it right or wrong is a relative view of how the rods internals are dealing with the force you are applying to the rod. Stress math is a constant. It amplifies the dimensions so you get a sort of expanded view of how the cross sectional areas of the rod are yielding to deal with the pressure you are applying. Anyone can jump in here and put a more scientific feel to this.

This is the tapered torque wrench I talk about. Picture a torque wrench with a tapered shaft rather than a straight shaft. The nut/bolt is the line (the resistance). Pull on it, a backcast. now picture a lot of little readouts up and down the shaft. It is easy to visualize that the smaller end of the shaft, toward the nut, is going to bend more than the fat end (The handle). This isn't exactly how a rod works but close enough for now. The readouts are showing you how much stress there is at each station. The only thing you really feel is through the last one at your hand. but through it you did feel how the bar was bending if you let yourself. That is the stress graph. All  the  readouts  are  in ft/lbs..in/oz along the shaft. SEE IT? Don't pick at my crummy analogy.

The reason I am going this way is I don't believe you can develop tapers unless you understand how they work. And this is the first tool that gives us some insight. or you can spend a lifetime doing the empirical thing. Trial and error. You still have to test each new taper, don't get me wrong.

Now that you have your line to cast, you have a BASELINE. It isn't really 100% transferable but you now have a basis to compare all rods. That Distance represents a weight. The resistance load that makes the rod work best for you. Take note of the shape. If it jumps around a lot you can mentally draw an arc through what looks like an average of the peaks. It doesn't matter what the shape is, it is obviously one you like. Note the peak value of the tip turnover, the butt values, and where the mid lies. The mid and butt relationship is most deterministic of the rods speed. low numbers, 140k and below are stiffer. faster. and some point, agin for each of us, you get to the point where you can't feel the rod bend. It is really bending everywhere, it's just below our individual feel threshold. The tip is just along for the ride. It is only relevant during the cast when you have offloaded enough of the mass in motion that it can exert it's influence. It is important, don't get me wrong. It must be synchronized with the rest of the rod or you will get all kinds of dandies in the line.

If you now go to any other  rod of the line wt. you picked and put that distance in the line to cast. Rounded off. You will get a direct read out of it's relationship to the rod you like. Is the new one higher on the charts (softer, slower),  or lower, (stiffer, faster). Next, search around the database and find a rod of a similar shape in another line wt. and put various line to cast distances in them until you get kind of close to your target stress values.

You should end up with a very proportional line to cast distance. GO DO THAT NOW.  (Jerry Foster)

OK Jerry, I now know the stresses of my favorite rod (a 8'6" 4 piece 5 wt with bamboo ferrules). If I want to make a 7'6" 3 piece 3 wt that feels the same can't I simply put the stresses into Frank Setzer's Hexrod program to find the appropriate dimensions for the new rod?  (Jim Healy)

Not there yet, but.....

Yes and no, mostly yes, and mostly no.

It has to do with synchronization, timing, (and maybe frequency, but I know nothing about that.)  (Jerry Foster)

It's a game of percentages and ratios. You'll have to spread out the same stresses you have on your longer rod to your shorter rod at relative spots on the shorter rod.  (Ren Monllor)

Thanks guys for stepping up..This is not a freebie...I ask that you do a little thinking and a little work... The purpose is to make you, force you to find the relationship between the picture and the feel.. Once you have that,  you don't need me anymore. You WILL intuitively understand.  So you  have taken the first big step.. you can find the sweet-spot and see the picture of it. But you must do the casting, sorry, just making an intellectual exercise out of it will only go so far..... This will annoy you,

If you can make a printout of the stress curve for your rod. Back to the street, with your tape, the rod, and the picture. NO HAULING, DOUBLE HAULING, that is not a test of your feel (bamboo) that is a test of your timing (tupperware). This part is about feel...

Now find another rod in your quiver if you have one and take that one with you also..You can repeat the same exercise as before with that one after you are done with the original.

This is a dance with the one you brung thing.. whether you think you are an adequate caster or not I doesn't matter, it's your sense of feel you are dealing with, not competing with someone else.

Now work out the line slowly this time.. where does the rod start to give you a good feel, you don't have to tell me, I just want you to do it. Note that distance. Your can rework your stress graph later and see what it yields..  now go out past the sweet spot and see where the rod stops working, note, the same...no fair shooting or tugging on the line, that distorts the baseline and the readings. At this point you could care less how far the rod casts.

Now with the stress chart in view. Go back to the sweet spot and "Be the rod" this is for the Zen group. What I would like you do is concentrate on the feel only see if you can tell things about the rod that stress charts are showing you, can you kind of get a feel where that tip transition is, if the rod has any other compounds, can you feel them, picture them in your mind as you are casting and just make believe you can feel them..once you get a rhythm, CLOSE YOUR EYES, feel for them.

Now you should have 6 different printouts . a short range, a medium (Sweetest), and a long range for each rod. And you should have worked up a sweat trying to turn yourself into a power fiber..  hehee. Sometimes this isn't easy Bret and Harry and you other accomplished  casters have the feel thing down pat, the rest of us have to develop it it you don't have it. But you must.

Why is this important.? What does it have to do with tapers and rod design?  (Jerry Foster)

Odd that hauling or double hauling is not appropriate.  If the caster usually casts with a single or double haul, then why shouldn't he or she do so when testing a rod?  Is it because the calculation of the stress curve cannot consider how the rod loads when hauling?

My question is not rhetorical.  When trying rods at fly fishing and cane-rod-building gatherings in Europe, it seems like at least 85% of the casters use a double haul all the time, whether casting close in or at distance.  At similar gatherings in the US, single or double hauling is very unusual. On both sides of the Atlantic, the casters involved are highly skilled.  (Tim Anderson)

I agree with the considerations of Jerry Foster. I will try to explain with my poor English.

During the last Italian Gathering in May I spent same time with Gabriele Gori and Claudio Biagi. In my opinion Claudio is one of the best caster in Italy of the last generation, formerly instructor in the Italian Casting Scool SIM and good friend and  disciple of Roberto Pragliola, THE Italian Master Caster and father of the TLT (Total Casting Technique).

Well, we have spent a good amount of time to test same of my quadrate rods. The casting technique that he use to test rods is absolutely without haul. He prepare 3 large circle of line in is left hand and only with the use of the right hand, after an adequate number of false casts, he made the shooting of the line that send out the tip top the circles of line.

He continue with a series of "casting and shooting" until the last shooting is unable to "shoot" the line circles.

That is the limit of the rod. The Natural Rod Limit.

After that point the caster can start to operate with single or double hauling  to increase the speed of the line and arrive to longer distances: but after the NRL the distances are function of the ability of the caster and not the taper quality.

More skilled the caster, more distance of the line.  (Marco Giardina)

Tim that was a great post.. I hadn't considered that people who DH couldn't not.

And some of the guys I know have kicked around what hauling does to the cast, exactly what does it do?

I have my own opinion of what hauling does, but could some of you give it a shot, It might be more of a variable than I had previously considered.  (Jerry Foster)

I have always thought that hauling increased the load on the rod which, in turn, increased the line speed. It can also open the loop. (Jim Healy)

Hauling increases line speed (not sure if increases the load on the rod) which means more line control, which should result in "tighter" loops.  (Lowell Davis)

Some thoughts on casting..

If the line is "hauled" it increases the load on the rod (The spring/lever), and acceleration happens, ergo, faster line speed. Shoot line on the backcast, and it will further increase the load on the rod, then while the spring is under this increased load, make a line haul on the start of the forward cast to further increase the loading of the rod/compressing the spring even more. Then you can expect that the rod under this increased load will further accelerate the cast, when the "stop" is made at the end of the forward casting stroke, and the spring unloads. The caveat is not to load more line than the rod can handle on the back cast, which can overpower the rod.

All rods have a sweet spot, (Some are sweeter than others), as to how much line they can load. The trick in casting for distance is finding the optimum amount of line that you can aerialize, without collapsing the rod and having good technique. Then being able to transfer this maximum length of line, along with loading the rod, into getting the rod to unload and make the cast.

Maximum casting distance does not come from the maximum carrying capacity of line in the air. Rather it is the amount of line that can be held in the air, with the ability of the rod to unload, coupled with the casters technique. If it was just brute force and ignorance we would be having casting tournaments at the half time slot of NFL games. It is easy to overload any rod with too heavy or to much line, when this happens acceleration of the line is restricted to the haul that the caster can generate, against the loaded spring. The spring is under too much load to function as a spring when there is too much line in the air. A maximum amount of line in the air does not translate to being the longest cast.

The factors of technique, and strength come into play. The best  technical caster  that I  know weighs  in at  about 160-170 pounds he is not in the muscle mass league as Steve Rajeff and others, so he has to be competitive with having better technique, the fact that he is starting to weigh the options of taking Social Security at his age is merely coincidental.  (Peter Jones)

The size or height of the loop is controlled by the path of the tip of the rod.  Has nothing to do with line speed or hauling.  Higher line speed does not translate into tighter loops, neither does hauling or double hauling. (Chris Raine)

I think that hauling may have something to do with loop size. I think hauling the rod loads it more, BUT specifically puts more bend in the tip section AND at a very specific point in the cast. This is because it is a short sharp movement and, as we all know,  has to be timed perfectly.

The best example I could give of the effect  is waggling a rod to gets its feel without a line. If you waggle it slowly and consistently side to side you can get it to bend in the lower butt - it effectively sways from side to side. But if you give it a short sharp flick of the wrist the bend moves up the rod to the middle of the tip - exactly where depending on the speed of the rod and where the rod taper 'breaks'. I think hauling imparts the latter sort of bend to the rod, which in turn makes less deviation in the tip trajectory. All other things being equal (e.g caster's strokes), faster rods (with stiff butt and mids and lighter tips) will naturally cast tighter loops. I think hauls to a certain extent do that to any rod.

So to answer Jerry's question about how you take the effect of hauling into design consideration I would say it is extremely difficult and requires dynamic modeling. That is because it is a very short period of rapid change in a dynamic process.  (Steve Dugmore)

It isn't that these people can't cast without a haul, it is just that they seem to prefer casting with one.

Interestingly enough, Charles Ritz made quite a point of the utility of always using a haul.  Without checking in his book, I seem to recall that he wrote something about the left hand being wasted without hauling.  If anybody is curious, I usually  cast without hauling.  Heck, while fishing, I often have more leader than line out.  Don't need a haul for that!  (Tim Anderson)

So far as hauling, singe or double, goes, it certainly makes a difference in distance casting.  I'm fairly new to bamboo, but I can tell you unequivocally that with graphite/carbon rods it makes a huge difference, especially in a headwind.  I'm not very good at double-hauling (see #1 son for lessons on that), but I single haul often, though I fish most close up and am fairly good at roll casting with either hand.  I'd direct you to tournament casters for a better idea for just how effective hauling can be. Not much interested in that myself, since, as I've alluded, I do most of my fishing in close proximity to my imagined fish and roll mostly.  Still, from what I've been able to ascertain, the tip is driven/hauled against the opposing weight of the flying line a bit harder  in an opposite/forward direction.  Sure works when you get it right.  I get rusty on doubles after a long winter.  Singles are natural and easy.  See Joan Wulff for more.

Good discussion.  (Bob Brockett)

And then there's Troy Miller.  He double hauls even when he's dapping...  (Mark Wendt)

The real casting geniuses have debated the question of what a haul does at great length.  Current consensus of opinion is that a haul only causes the rod to flex more deeply.  In a correctly timed haul the increase in line speed does not occur until after the haul is completed, the line passes beyond the tip top beginning loop formation, and rebound of the rod beyond the Rod Straight Position has occurred.

Not sure I understand all that, but it does make some sense to me.  (Harry Boyd)

Yep, as I have seen it argued there seem to be two camps.. the loaders and the speeders.

I do understand both arguments but we are rod makers... how do either work,  act upon the rod,  (there is no magic, some physical principle is in play). Al, a good place for you to add some theorem. (English please )  (Jerry Foster)

I have not been getting all the emails on this topic series in a timely manner so I may have missed some of it so that may be why I am confused or hopefully what I say will not be to far off topic. That said, I am not sure why one would test a rod or compare rods and not run those rods through the paces. I mean there are times when I fish I just pick it up and put it down but most of the time I am doing a lot more. As to double hauling, yes, you can speed up the line and yes it does load the rod. I mean, come on, your telling me that when you speed up the line and then turn it around that that doesn't put a load on the rod? As far as why to double haul, I can't imagine not hauling. I like that "wasted left hand" LOL. You use the haul to manipulate the line a lot of different ways,  flip the fly to the left or right, use the haul to suspend the fly mid air to time the drop. Also, you know when we teach casting with graphite we say speed up the rod and stop and the line turns over. Fact is you can sure make the line on a willowy rod bounce doing that or trying to increase your distance. So, you can load your rod by stripping the line through the guides as well as speeding up and stopping it with a shock. Why else haul, how about turning over the tippet when you roll cast. You can shoot a roll cast with a haul. You use your haul to maintain your cast, in air, on a windy day. If the question is what does a haul do to the rod I suppose it would be the same as increasing the length of line. How else would you graph it?  (Timothy Troester)

I think that's why Jerry said to evaluate with no haul

Too many variables.  (Ralph Tuttle)

Well, I'm not sure whether I am talking to Jerry, here, or about Jerry, hmmm... Anyway, okay, in that light, Ralph, I really like the project Jerry was talking about the other day where he made a bunch of different rods each illustrating a specific characteristic on a stress graph. In that setting where you line up the rods and can pick up each rod and put it right down, yeah, that's a cool idea. I like that. As a matter of fact I could spend an afternoon doing that. You all go eat your burgers and leave me alone! Speaking of Jerry's projects, I also want to see an eight sided hollow rod. I want to cast one. I also would like to be present at a demonstration of gluing a rod with rubber or contact cement. Okay, I hope I didn't upset the apple cart with my tirade. I'm trying to keep up. (Timothy Troester)

A haul is adding more force to the line/rod causing the rod to bend more. The INSTANT you start adding more force you are accelerating the line to a greater speed than before.  The rod bends to absorb most of that force and then gives it back as it unbends causing greater average acceleration over the stroke hence greater overall line speed throughout the stroke, not just at the end.  The rod's stored energy causes it to travel past the Straight Up Position to some point forward of Straight UP.  The instant the tip stops, the rod has given up all the energy it can to the line and the line is at its maximum speed.

That's what I think.  (Al Baldauski)

I'm in agreement with this, but here's something for you tech guys to think about, In addition to the benefits already discussed, I also think you can get a bit more power into the cast by hauling because you are applying the power stroke to a momentarily stiffer rod, and therefore can apply more power without shocking the rod. The haul causes the rod to load more fully, stressing the fibers, making it stiffer when the speed up and stop is applied at the end of the casting stroke. The caster can therefore apply more power with the casting hand without shocking the rod. That's how it feels to me, make sense to anyone else?  (Tom Smithwick)

The two of the most noted and knowledgeable people on the list, Frank and Al, have given the same hi level definition as everyone else on the list and has given, and then applauded each other, wonderful  :). Kind of like the rod loads on the forward cast. Please tell us .. previous down/up posting when and how that happens. The reason I am prompting you is to try to consider how this can be better accommodated in the design phase.

Tom, that probably is true, because on a well executed haul it occurs while the rod is in motion and just smoothly amplifies the stress already accumulating.

Now a little about design.. The reason I asked for no haul is because, as everyone is in total agreement, this technique adds to the rods stress. I would like to see people get the feel of the rod in it's normal ranges with no exaggeration. If this is impossible for you to do without hauling, then by all means haul away. But also be aware that some rods don't like to be hauled and some almost require it. They can be another design type.  Distance Tournament rods come to mind.  (Jerry Foster)

I'm not sure how I can be more specific.

On a "normal" cast, the rod begins to load the instant you "stop" on the back cast.  At at that point the moving mass of the rod is loading itself. Sometime after the stop the caster begins to move his hand/arm forward. At that instant, he is accelerating the rod and line behind it, increasing the line's speed.  It's not easy to define because we've already agreed a thousand times over that every caster is different applying force in different ways over different distances.  You almost have to use the rod to define the caster.  The rod he likes defines his personal stroke.

In the case of a haul, all of the above applies but then you add the "haul stroke" somewhere in the middle of that cast.  That creates some additional force on the line/rod system, bending the rod and accelerating the line more than you could with no haul.  Results:  more line speed. 

Tom, by definition, that means more power.

If I haven't addressed your question adequately, I know you'll say so.  (Al Baldauski)

I am not sure what you mean by "knowledgeable" in my case (I think Al is OK) since I have all those "scripts" after my name   -  and you all know what they mean. :>)))))

I agree that trying to correlate the feel of a rod with the computed stress curve is a good way to focus on taper design by each person. Hauling the line adds to the normal rod loading through the casters applied forces - each caster being different. As I have pointed out in the past, the casting process involves a system of rod, line, and caster; for a given rod and line, the caster becomes the variable in this process whether hauling or not.

One interesting point that I have observed in my casting process is that the forward and backward casts are not the same; conceptually these should be the same but our physical arms are not constructed to make that possible.  I have done some casting with the Michigan/3M casting analyzer in the past using a carbon fiber rod and realized that for me, these two dynamics are different. My sense in deciding whether I like a rod taper or rod is based on an integration of both casting directions. I would expect that each caster does that in an integrated way as well.  (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)

I like your thinking Al, but would mention that you made my point in your own rebuttal.  When you say "The rod bends to absorb most of that force and then gives it back as it unbends" you have it almost exactly right.  The force is absorbed by the rod, and that causes the rod to bend more deeply. The line is still trailing the rod and its speed (in an ideal cast) is constantly accelerating from the moment the cast begins until the instant the rod unloads and the line passes the tiptop.  But hauling doesn't make the line move faster, just moves it forward by the same distance it is tugged.  Because we pull on it, the line doesn't get faster until the rod unloads (straightens) and the line passes the tiptop.  The real speed is from Frank's "system" of bent rod, weighted line, and moving hand/arm/shoulder/body.

This isn't something I figured out on my own.  This is the accepted wisdom among such people as Bruce Richards, Gordy Hill, Art Mazzier, Paul Arden, and others.  As Frank mentioned, their work with the Sage/3M casting analyzer has proved it to be true.  (Harry Boyd)

With all due respect to the you and the gentlemen you named I believe that you have misstated or misinterpreted their ideas, or they're wrong.

If you take a snapshot of the system at the instant you begin the haul, you "freeze" the action.  At that point the tiptop and the line are at one speed.  In the next instant, when you begin the haul, you begin to, as you say, "move the line forward by the same distance you tugged".  In order to "move the line forward relative to the "freeze frame" you must accelerate it to a velocity greater than it was.  Therefore you HAVE increased the line speed.

Not all of that tug goes into moving the line.  Some, maybe most goes into bending the rod.  The more you bend the rod, the more force it has, at any instant, to accelerate the line.  The instant you start hauling you are accelerating the line, hence increasing its speed  (Al Baldauski)

I checked with a friend and casting guru about the discussion between me and Al and others on what a haul does. Here's his comment:

Thanks for CC' me on this.

My take is that Al is correct in that the haul accomplishes two things.

1. It primarily increases line speed.

2. It increases  rod bend and, therefore, rod load.

Bruce Richards and physicist Noel Perkins have been making some interesting observations as they refine their new Haul Analyzer

Looks like I've got egg on my face. Sorry if I steered anyone in the wrong direction.  (Harry Boyd)

I'm trying to give consideration that over the duration of the haul we have also shortened the mass of the line by the distance pulled, lets say 2'. Which dynamically is about 2 line wts. less than whatever it was.

I'm trying to visualize what happens if we were to reverse the process. Start with our hand 2 ft down the line and feed it in during the stroke. up/down. Not like a shoot, but a controlled extension of the line. As the English Guy said.. =/opposite but  it alludes me.  (Jerry Foster)

First let me take exception to your estimate of the effect of 2' of line. My deflection analysis shows that with a rod that is normally loaded, 5 feet of line is equivalent to 1 line wt.

Now, if you let out two feet of line throughout the forward cast, you are reducing the force on the extended line and allowing the rod to unbend somewhat.  The net effect is that the line will not reach as high speed than if you had not let out the extra line. 

Putting it another way, you've let out a certain mass of line which has no forward speed so the "system" has to supply the energy to get it up to speed.  The peak speed will be less.  (Al Baldauski)

Yes, Of course you are correct on the line wt.. I did mean to type 2/5. It's not 8:00 here yet.

I hope you understand, I'm not arguing with you about any of this, Just my way, in  my ignorance, of reaching some level of quiescence (understanding)

The imponderable in all of this, is that I know the human machine kicks in here somewhere, and tries to prevent bad things from happening. Like in the real case, I'm still not sure there isn't an auto-compensation by the caster to the increased line speed that causes the deeper deflection.

I will continue to listen. (Jerry Foster)

In one of our discussions I think we decided that the caster doesn't react to the haul.  In reconsidering, I believe  he does, however little or unnoticeable.  The act of hauling applies more force to the system which the caster must counteract or else the rod DOESN'T flex more and the line speed DOESN'T increase.  So, at the instant the haul begins, the caster unknowingly exerts just a little more forward force.  (Al Baldauski)

But then how do you explain those who can cast an entire fly line just with their hands,

No rod, using a double haul?  I agree that there are two different functions to the double haul, acceleration and increased rod bend, and would argue that acceleration us the dominant effect (at least with my casting style ).  (Chris Obuchowski)

Remember the rod is just an extension of the arm. There are casters whose arm geometry, flexibility, and strength permit them  to do just what you say; for most of us, we need to use this arm extension called a fly rod.  (Frank Paul)

Being slow, lets slow down the down/up for me.

Start forward cast with one hand, start down with the other. What is the line doing?

Full down with the other, where is the one hand? What is the line doing?

Start up with the other, where is the one hand? Same?

Full up with the other, where is the one hand? Same?  (Jerry Foster)

Harry and I are of the same mind on the haul; double or single. Most of this was sent to Harry prior to sending it to the group, because I get stupid late at night and don't hit the "reply all" button. I know damned little about rod taper engineering, and there are some that say I know even less about casting, so take this for what it's worth; it's free, worth nothing.

The way I approach the haul is as a technique that allows me to get the same or more potential energy into the cast with half as much work. If both my hands equally share the load, then I put the same, or more, bend in the rod as I would if one hand was doing all the work. That's the true beauty of the haul: less input and more output.

A haul will not give me higher line speed. It will not give me tighter loops.  It will not necessarily add more bend to the rod. Power, rod stop, rod arc and stroke length will give me these things, and the nature by which I haul will either help or hinder the outcome.

A haul will help me wrap a cast behind a downed log, rock or a boat dock with a hook cast. It will allow me to hover a fly under a willow branch and drop into the pocket behind the branch with a skip or a parachute cast. I can certainly cast longer by loading the rod deeper into the butt using a long, smooth haul. A very short, quick haul will load the rod tip and turn over just 5 feet of line and the leader.

Now it's very easy to bend most cane rods, but y'all know that, right?. Just a little haul goes a long way. I may end up casting so softly, with both hands doing so little work, that it almost looks like I'm not using any effort at all. And that's what casting should be; effortless.

A rod that I want to use for small stream fishing MAY NEVER get loaded into the butt section, with or without a haul. The casting distance for this rod will be in the 10' to 40' range. It'll be a rod with a tip that's easy to load and quick to recover. Probably something with a straight (compound?) taper that loses a lot of material in the upper 1/3 of the rod. For big water or big, wind resistant flies, I want a rod that is easy to load way down into the butt, and has a continuous and smooth unload all the way through the tip. This rod may even lean to the parabolic side of the spectrum, but not too much. This rod will reach out from 25'-30'  to 75' or more.

So, you taper designers, ask your clients some questions about how they intend to use the rods you're designing them. If any of you need a test pilot, give a call.  (Ken Cole)

Okay, let's move forward.  I went out to cast my copy of the Payne 101, lighter tip, which is listed in Hexrod.  I like it best with 40' 3" of fly line beyond the tip top, and a 7.5' leader.

That gives me a maximum stress of 156,619 at 15" from the tip.

For the sake of the exercise, now what?  (Harry Boyd)

If I have the right taper I would say it's not a light tip but a heavy tip and more of a light butt. You didn't say what line size you are using so I guess a 5 wt. Regardless, if this taper has .222 at 50, 225 at 55, and 239 at 60. it has a longer hinge or flex area from 55" to 75" (note the increase in stress at these values). This gives the rod a rather soft butt and strong tip making the rod feel slower and heaver at line lengths greater than 43'.  I would think the Payne that I have, Not sure where I got it, will be a much faster smoother taper.  (Bob Norwood)

Interesting that you mention the Payne 101.  Of all the rods I can choose from and knowing I'd be fishing 3 rivers new to me, I selected 3 bamboo and on those windy days a graphite 9'-6" streamer rod, to take out West.  At least 90% of my fishing was using the very first rod I ever made - a Payne 101 using Maurer taper.  (Doug Alexander)

I took my favorite rod, which is in the online Hexrod archives as "South Bend single built Cross Sylph," across the street to the park and it seemed to want to cast 37’ not counting the leader and without any "shoot."  The rod is listed as a 5-wt but I use a 6-wt triangle taper (I weighed the first 30’ on a reloading scale and it was 165 grains which is about a 6 wt).

Its a muggy, overcast, still evening; the fireflies are popping and the mosquitoes are thick.  What a sweet night to be on a little marshy stream with a flashlight and a few hex trudes.  (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)

To complete the information for Jerry, the rod as loaded has stress   peaks   at   15   (f(b)=148,508)  and  50  inches (130,986). (I don't know if what is below will format plainly for everyone.)

===============================

Design Report
South Bend Cross Sylph - 7ft 6in 2pc 5wt

South Bend Single Built Cross Sylph - 7ft 6in 2pc 5wt
Submitted by Bob Maulucci Aug 19, 1998
Parameter  Value
Geometry:  Hex
Rod Length:  7 ft 6 in (=90 inches)
Action Length:  6 ft 9 in (= 81 inches)
Line Weight:  6 DT
Pieces:  2
Line Fished:  35 ft
Tip Factor:  1.785
Ferrule Type:  Standard
Ferrule Sizes:  Computed
Ferrule 1:  Size 14/64 Wt ~0.328 oz.
Rod is 13.63/64 (0.213 in) at 45.00 in from tip
Outside diameter (around apexes): 15.74/64 (0.246 in)

Point
(Inches)  Dimension (in)   Stress

0               0.072                     -
5               0.086               120960
10             0.107               130442
15             0.119               148508
20             0.145               114810
25             0.164               104733
30             0.185               93050
35             0.196               97588
40             0.205               104601
45             0.213               112783
50             0.218               130986
55             0.238               122381
60             0.257               116189
65             0.281               104957
70             0.300               100940
75             0.336               83519
80             0.376               69000
81             0.376              71031  (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)

Sorry to be a pest, but I'd like to return to the (interesting?) question of rod design.  Not that the haul question isn't interesting also.

Anyway Jerry had us cast a couple rods, noting the cast lengths at which they began to "work", their "sweet spot" and where they stopped working.   Then get the stress curves for these length of casts and meditate on the relationship of the curves to the feel of the cast.  He ended by saying "Why is this important.? What does it have to do with tapers and rod design?"

Jerry, I waited a while for you to answer, but I suppose you intend that each of us answer it for ourselves.  This is interesting and maybe even true in a postmodern sort of anarchistic world where "whatever" passes for high praise. But I find it less than satisfying.

Maybe we should move on to a couple more specific questions, which have been touched upon in this discussion: power transfer and tight loops. Are there any principles of rod design that lead to good power transfer?

Are there any principles of rod design that lead to tight loops?  (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)

I may be all wet here, but just as a place to start, I've always found a rod with a light tip easier to make and maintain tight loops with.  Of course, light would be relative to overall length and intended line weight and usage, I guess.  (Bob Brockett)

How many types of rod actions are there? ...  Wet fly action.. etc.. can we name them?  (Jerry Foster)

I think you are screwing with us..............

But here is a start, Soft, Stiff,  Quick, Slow, English wet fly, Parabolic, Semi Parabolic, Tip action, Mid action, Butt Action, Parametric.

Any of the above can mean anything to anyone, at any time, and frequently does.

Aghhhhhhhhh..........................  (Peter Jones)

Add a few like, Medium, Progressive, Dry Fly, Full Flex, Nymphing, ect, ect.   (Jim Bureau)

And Hi Peter..hehee, no, I wasn't screwing with anyone this time...

There are two obvious approaches from the responses so far.  Those who use rod speed, (fast, med, slow) and those who use more descriptive language..

The thought was, some guy meets you in the store and sees your  logo shirt  and says,  "Can you make me a streamer rod?" Of course you can, but does your mind bring up a particular shape, or do you have to run home and see what a streamer special looks like?

There are probably n kinds of rods and they may all correspond to a particular kind of shape (stress). As we call ourselves rod makers, surely we can know that much about rod making. Maybe not.

So maybe one at a time

Dry fly action...  what is a good picture (representation) of this kind of rod?  (Jerry Foster)

I will go along with you for a little with the "two obvious choices", rod speed, (fast, medium, slow), or  "more descriptive language". The problem is how do you quantify by definition?. This group for example has a tendency to want absolutes, and I don't know how to get there just with descriptions.

Dry Fly Action, my mindset says this is going to be a quicker action rod, but the door will always be open to invite comparison.

Three rods/tapers I have spent some time fishing dry flies with are the Garrison 109E,  Paul Young Martha Marie. and a Dickerson 7613. The 7613 is a decidedly quicker action than the other two. All three rods fish dry flies the most, but are not  opposed to a few soft hackles and the occasional muddler. All have very different rod actions, different pace in casting action.......... All dry fly rods?

Descriptions by definitions from each of us are going to be subject to interpretation. We are all going to have to cast the same rod and check the boxes as to fast, medium, slow, and tally the results with which I am sure we will all agree with.

This is not going to solve the "What action do you want" question from the rodmaker to the purchaser. I would want to put several rods in that persons hands, and ask "Which do you like, Is this what you want?" and work from there. If he doesn’t have this option, but says "Just make me a PHY Perfectionist". Then there will be a lot more to define by all.  (Peter Jones)

Actually, the only actions I have heard of are: fast, moderate and slow and some in between. I can't think of what a wet fly action is!  Most of my wet fly fishing is done with a 10 ft moderate action rod.  (Grant Adkins)

Pretty much what I was getting at, though you put it more succinctly.  I think I know what 'fast' is, but if you've cast any of the newer plastic/graphite/carbon/boron/whatever-you-want-to call-ems, those can be incredibly fast, much quicker than I imagined possible even a decade ago. So what we call fast for bamboo has to be graded on a seperate scale.  I prefer the bamboo, naturally (no pun).  Seems to me, you work less to get the fly out to a reasonable distance and everything from the leader to the fly to the fish appreciate a softer landing.  Where it comes to 'slow,' well, if you ever seen my Uncle John, you'd know what that means!  (Bob Brockett)

The folks at F.E. Thomas listed six rod actions available from their company in at least four models:  The Bangor Rod, Dirigo, Special, and Browntone Special. Not to mention the Streamer Special and possibly others.

I'm trying to remember all of the actions but I can't right now.  Three were listed under Dry Fly and three listed under Wet Fly.  I'll have to go back to some reference materials.

After casting a whole lot of FETs, my guess is that they did not have specific tapers for all six.  I think they simply made rods, gave them a wiggle, and declared their action.  (Reed Guice)

I don't have too much experience with these things, but I thought there were only two rod actions: sweet and not to my taste (AKA crap).  (Dan Zimmerlin)

You know, Dan, I think you are pretty well right on the money here.  There has been a little thread on shotgunning here in the last few days, and there is a great similarity.  When i was a shotgunner, there were skeet guns, trap guns, trench guns, field guns and Lord knows what else.  They had differing barrel lengths, stock lemgths, comb settings and rib heights.

But in the end the blokes who shot the good scores, the REALLY good scores were those who had the  gun fitted by a competent fitter so that  it was right for that shooter.  When the gun came up to the shoulder, the master eye was looking down the rib at the correct angle and the gun moved well with the line of sight.  I had a couple of beautifully fitted guns, a Beretta, a Winchester and a Stephen Grant, and I could shoot pretty well anything with them.  With the Beretta especially.  I have often shot 50/50 skeet with it, and best trap break with that gun was just under 300, and it was also my field gun for snipe and ducks.

I think the same applies to rods - if you get a rod that suits you, that operates at your speed and in sympathy with your casting style, you will be able to use it for pretty well any type of fishing and/or casting.

The actions available in this paradigm, then, are (1) those that suit me and (2) those that don't.  How you design them, though, is beyond me.  Up to now it has been a hit and miss thing.  (Peter McKean)

Another "vote" for "suits me or it doesn't":

Coming back from the Colorado gathering and conclave, one of the things that struck me was how you can watch one guy cast a half-dozen rods, and just watching from a distance, not knowing what rods he's casting, you can sometimes say  "There!  That's the rod for him!"  Of course, some guys at those meets can pick up any rod on the rack, club or wisp, and make it do whatever he wants, in a beautiful lack of effort.  But many of us have a narrower range of strokes, and only certain rods really fit.

For that "normal" guy that you're watching, some of the rods, his timing is off, too early or too late, and he throws a mix of tailing loops or open loops into the ground, and as soon as he puts some additional line out, problems magnify themselves.  But then one rod clicks for him, the timing works, his loops tighten up, he drops tippets where he wants, and he gets another 10 or 15 feet out without thinking about it.

The funny part is that if you talk with him, he may not have noticed that that one rod was the right fit for him.  He'll talk about the nice finish of one of the other rods, or he'll talk about the rod upon which he read "Payne 98" (or whatever), or maybe he'll say "Yeah, I guess that one rod did feel pretty good...", as if it's news to him.  I'm sure that many of us can grow into better casters, but I'm thinking that it's easier to get better if you start with a rod that fits your natural rhythm and stroke, get good with that, then expand your skills.

Sometimes I wonder if part of our job as rodmakers isn't just sometimes to try to help those "normal" casters see what is right in front of them.  (Lee Koch)

When you are looking at tapers, or designing your own tapers, how much attention to guide placement and size do you consider?

Chris Bogart has a George Varney rod he has shown at several gatherings that had a step in the taper at the guide locations.

That would take some planning.

Also, in need of the guide spacing for a Granger or WM 7030 in the shop for rewrap? (Scott Grady)

All rods perform better with lighter rings, the best rings therefore have zero weight.

The nearer the tip any ring is placed the more its weight detracts from the feel of the rod (point heaviness) it's rate of recovery from flexing and the weight of line it will throw.

The rings fitted to nearly all fly rods are too small, too heavy and too numerous!

As for placement then I must say that when I looked at this many years ago there seemed to be no detectable difference between the alternatives, this was a whiteboard action curve test.

I don't want to upset George Varney, whoever he may be, but it would gladden my declining years to hear a justification for step tapers in any fly rod anywhere.

Putting them at the rings turns comedy into farce.

Has he never heard of stress raisers?

And why do you want sudden breaks in the action?

No competent rod designer with even a scrap of technical knowledge would countenance such an idea.

I see that the "Guess and Hope" fraternity are still with us.

What is wrong with doing it properly?

It's quicker, cheaper and produces much better results consistently. (Robin Haywood)

I was not considering making any taper adjustments, more of the thought of where guides should go, how many are too many or too few, what size, etc.

George Varney was a rodmaker from the early 1900’s who worked at/with several of the rod companies at the time.

Maybe Chris will chime it, not sure if he is on the list anymore. (Scott Grady)

To push your note a bit further, suppose you were to build an eight foot 5-weight rod, what size range of snake guides would you use on it?

I used use much bigger guides than I now do; not really sure why I changed to smaller guides. But I would be very interested to know your selection. (Peter McKean)

I can understand rings as in guides like stripping guides having appreciable mass such that using the smaller sizes would matter but snakes???

Compared to the mass of the varnish filled wraps that hold the snakes is there a REAL dif between the sizes that you'd consider for the location worth anything at all?

We're talking fishing rods here aren't we? Not a return trip to Jupiter? (Tony Young)

Where weight and rod action are concerned, I hardly notice any difference using the largest snakes vs. using the regular sequence of progressively smaller guides as they go up the rod.

Where casting distance is concerned, I notice a HUGE improvement by using the large guides, especially when double-hauling, and when NOT using shooting heads with Amnesia shooting line.

The oversize strippers make a smaller difference, but still significant, most pronouncedly above 7 weight lines.

To me, it's a no-brainer. Use the large snake guides. (Casey)

Yep, that's what I find. In use. Though I use progressively smaller guides, it's just a cosmetic thing but they're still on large side. I know the idea of small snakes is to keep the line on the straight and narrow but I think it's better to let it go with the flow with less restriction. (Tony Young)

Well, I quite agree with you!

I did try to make a distinction between thunderpoles above say a #6, which I use often, with few very big rings, and lighter rods of, say, #5 and below.

Distance is not important in these rods, because casting distances involve the use of heavier lines, so smaller, lighter rings convey some advantage, the lighter the rod the more advantage, although I find little use for anything below a~3, and even that only on blue moon periods.... (Robin Haywood)

In my experience, using all the usual materials rods are made of, guide spacing is the biggest factor and should be adjusted for according to taper.  Having said that, if you fish 8 weights (or heavier) for steelhead in half-frozen water, you will quickly come to appreciate the larger snake guides for the ease with which they clear themselves of ice.  This is no small concern for the experienced steelhead/salmon angler. (Bob Brockett)

Can you be more specific about what you mean by spacing?

I am not, obviously, concerned with the actual dimensions, but how you arrive at them.
Is it a variable but arbitrary increase from the tip down, or a percentage increase on the rate of increase of a basic scheme?

You say it is related to taper, but excluding extreme wildness, the actual rate of taper, either specific across fixed points or overall, doesn’t vary hugely, and I wonder how you relate the rate of taper to ring spacing.

No doubt you have developed a handy algorithm! (Robin Haywood)

There are algorithmic methods, but I rely mainly on stress tests.  A simple matter of smoothing out the arc during the load of casting or playing a fish.  When I have a minute, I (or others) can post links that show there are a multitude of methods that usually arrive at nearly the same place, or at least with the same goal in mind.  For skeptics, begin by taking a blank of moderate length and using only 3 guides + tip top.  Hang a weight from the tip and move just these three around for best line flow.  You'll immediately discover that fewer guides may indeed be used if they're carefully arranged.  Where there is most bend (tip end) will require closer spacing every time.  These things have been known for a very long time now, but that doesn't mean we shouldn't test them.  Obviously, more guides will work better that just the three, but only up to a point and then they become just added weight (and labor).  In most cases, the added weight is of no consequence whatsoever to actual usage.  I'm with Tony Young on that one. (Bob Brockett)

First, I don't think stress curves are the ultimate in rod design, or that Garrison Rods are great for me.  Just so no-one thinks I'm a fawning Garrison addict. 

SC's are still a good tool to understand and the next step after just duplicating rods to understanding how rods work. 

Next, there will be homework...I don't know any other way to get stress curves across to anyone other than to say...You must own them..understand how they will work for you..It's always difficult for me to interpret  what anyone else says about a rod. I must see the deflection graph to fit it into my own frame of reference. 

First, basics... I hope everyone knows that SC's are based on beam theory... You don’t have to go there, it's already in the math of the program. 

I will use Frank's Hexrod form most of the examples... Everyone has access and it's easy to manipulate.    http://www.hexrod.net/Tapers/index.html 

I think it's time to give a big thank you to Wayne Cattanach... He developed the first software version based on the Garrison book... it was actually quite remarkable given the software tools available at the time. Anyway, Thank You Wayne. 

The inputs are known, but right away we run into problems...  

The first being action length... any guesses why? (Jerry Foster)

Ummm....OK, I'll take a risk and raise my hand.....you need to determine how long is the grip and reel seat are going to be? (Marv Loopstra)

Well, Here's my take on action length. I think the intention is to show the rod under it's fullest deflection. So, where do apply the power to make this cast. It is reasonable to assume that anything behind your hand isn't going to be involved in the bending action of the cast. So the reel seat is never a part of the equation to me. single handed rods here. Now I know this, any piece of bamboo no matter how thick will bend under enough load, so arbitrarily ruling out the bamboo under the grip doesn't make much sense either. So where is the point of power application. To me it is at the fulcrum point. I decided that was the mid point of my hand. The centerline of my wrist. roughly 2". so I use 6 " off the rod length as the action length. -4' reel seat-2" 1/2 for hand. I feel this allows for all the rod that wants to bend, to bend.  

Now for the proof, first go to hexrod and choose the 8'6" granger victory. Note the end dimensions .063-.375. now click on fundamentals and change the action length to 8' 0". click on hold constant stresses button... Next compute dimensions... Compare the dimension numbers. In only one case should the action length be at the top of the handle... That is for a wooden grip. And never ever should it be the full rod length. now experiment with your favorite rod/rods. move the action length around and see what changes in the dimensions. Now normally I would keep the dimension constant of course. But this exorcize shows that when designing rods from scratch the action length make a difference, and you will see if you now the dimensions constant the stress graph will change. The idea here is to get the best picture of the rod you can. 

Try it, get back to me (Jerry Foster)

Some comments on action length. I agree with you that about the right place for it to end is the mid point of your hand. However, if one is just doing a Garrison style analysis where the rod doesn't bend, it's not of much interest. For a given point, only what's further out on the rod has any effect on the stress at that given point. The exercise you suggest in Hexrod muddies the waters. When one does as you suggested, Hexrod scales out the original stress curve to the new action length which must result in the new dimensions, but that's now a different rod. Apparently, an example of the rod was mike'd by somebody and submitted. Now they couldn't measure under the grip or reel seat, so they presumably said the action length is where their measurements ended. I doubt that Granger specified that. So stretching the stress curve in this context is to me a leap into the unknown. I note in passing that RodDNA doesn't fiddle with the stress curve when one changes the action length.

Action length only becomes important when you consider analyses where the rod bends a la Max Satoh or Al Baldauski. For that you need a boundary condition where the rod stops bending which would be the end of the action length.  (Mike McGuire)

I didn't mean to muddy the waters but to show why proper action length is important to a proper representation of the graph. If you wanted to get a better picture, I would extend the last given dimension all the way to the butt. Flat through the handle. 

As to the bending aspect, stress is bending, a rod which is not bending is not under stress, other than gravity. The reason I was using Franks is because I don't want to get into dueling software. I'm not sure I understand the part about stress at a given point. The whole rod is under the same force when you start to move it. (Well not true because the tip is accelerating faster than the butt during the rotary portion of the cast) If you change any part of the rod the entire stress/bend curve will change slightly. Not just a part above here, or below there... Al could chime in here, but it has to do with iteration. (Jerry Foster)

I should state that I'm just trying to show how the ordinary maker can use stress curves.

If you see the raw numbers, and can extrapolate the rod, or you use rate of change/slope, or you use stress, or you use deflection it is your decision. I have found on my rodmaking path that each of these conventions is an aid and they have been accumulative in terms of analyzing rod action. Using deflection was the hardest to get my tiny brain around because it was the biggest paradigm shift. You don't even care what the numbers are, you only care about how you want the rod to deflect/bend. (Jerry Foster)

By ordinary, I meant makers like me. Those that aren't engineers, scientists, or mathematicians. I am aware you are all extraordinary rodmakers. (Jerry Foster)

The part about the stress at a given point--If you are using just the Garrison analysis, at a given point, only loads further out towards the tip contribute to the stress at that given point. Hence there doesn't seem to be much point setting an action length. While the stress curve obtained that way does give you an idea of the flex of different sections of a rod under load, the calculations are done as if the rod didn't bend at all. (Mike McGuire)

You might have figured out by this time that Mike is one of those mathematical people! (Tim Anderson)

Mike is correct.  Changing the action length alone will not change the calculated stress numbers, except to calculate them farther back toward the butt.

One piece of hexrod trivia:  If you have a rod with unequal sections, like a 7ft rod with a 4 ft tip and a 3 ft butt, you can trick hexrod into putting the ferrule in the right place by saying you have an 8ft rod with a 6.5 ft action length. 

On a more general note, I believe all the rod analysis and design tools can be useful, within their limits, to get the rod we want. Where all of them seem to fall short is at the ends of the rod. They don't tell us much about proper tip design.  No one ever ponders the tip end of the stress or deflection graph.  Same for the butt, especially when we add a swell.  We all know how it dramatically changes the feel of a rod, but I don't think deflection analysis helps us understand it.  I'm sure stress curves can't. Seems like we need a lot deeper knowledge of how a cane rod stores and releases energy to model the ends. (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)

Yep Frank... absolutely true.

Tips and butts are the most important, and least important part of rod design. And, no tool will design a rod for you. It's all about the known to the unknown. One must have some concept of the limits of stress that you and others can observe (feel), and then strike out from there. My basic formula is the 90% of the rod is in the middle 2/3rds. thats where the action can be changed and felt. The tip itself is the area from the high pt of the stress curve to the tip top. This is an uncontrollable part of the rod.  What I mean is, you can set a tip dimension and control the height and length of the transition zone (turnover point), but from the high point going to the left on the graph the rod is trying to get to straight. We all can agree that the tip is at zero stress, which is no bend. There is certainly no bend under the tip top itself. so that first 5 to 20 inches or so is rapidly going from some max stress to zero as fast as it can. Or form max bend, lets say in the 1 degree range to Zero degrees, so unless you manipulate the numbers the rod will head for straight by the most economical means. (Jerry Foster)

I may be putting my foot in it, but I do pay a good deal of attention to the last station or sometimes two at the tip. I have a theory that sharp stress peaks (within bounds) at the tip correlate with rods that will form tight loops without too much difficulty and protect light tippets. I do have to agree that they dodge the heavy work which I think you rightly attribute to the middle. This to me, is the region where smooth feeling rods have strength.

A small rise in stress heading into the butt, in my mind gives the rod a second gear. What I mean is a slightly parabolic action. I like a bit of swell in the last station going into the butt to stop the action.

Well, now, I think that I have exposed myself as a devote' of certain Payne rods. A great example of what I a speaking of is the Payne 200L (light tip). It is in Rod DNA.  (Doug Easton)

Your theory about tips and stress makes sense. 

I'm partial to a taper that has a two-humped stress curve, like the Cross Bataviakill in the archives.  Maybe that is just because I am used to it.  I do like some flex above the grip because I often pick the line off the water with a roll cast. Sort of the opposite of Robin's Superfast. (Frank Stetzer, Hexrod, Taper Archive, Rodmakers Archive)

Good point Marv.  And I'm wondering if thsat coulddoes go to a deeper issue of style and preference?  I've cast rods that were very "tip casting" (?) and others that I could very much feel flexing in the grip!  I like both in different situations, though I must say, to my tastes there's something very groovy about a rod that I can feel the action into my hand under normal, reasonable conditions.

To Jerry Foster, I'm guessing I'm not the only one who's lurking and very interested in this subject.  Please don't take silence for dis-interest!  Speaking only for myself, those of you who are in the know on this immediately went graduate level.  I very much appreciate your offer to start at the beginning.  If you feel there are better tools than stress curves, please educate us newbies through stress curves and beyond!!

I will say that I appreciate some of the nuances in the discussion so far, but I have no idea how to represent a stress curve, or any other graph, for a particular piece of bamboo.  I'd love to see how to generate that graph based on the dimensions and to understand what the graph then represents in relation to that wonderful piece of grass in my hand!  

I think that a fantastic education in this would come from relating the graphs to the feel of varying actions, and I believe that I heard Jerry had a road show that did exactly that.  A group of different rods that were similar enough to compare, but different enough in some basic ways that they did a nice job of demonstrating different actions and their relationship to their stress curves?   

Did I get that about right?  Wish I'd been there to play with those.  Absent your selected group of rods, I would like to be able to look at numbers for a bamboo rod and relate it to what I feel in my hand.  At the different Rodmaker Gatherings there are plenty of classic rods that I'd love to compare my impressions with the curves, and I'm thinking that might just lead to a little more understanding.

I'd appreciate any feedback from the group where I'm on track, or off base, and especially any education on this topic.  Thank you! (John Jazwa)

John, that is exactly what I hope to achieve in the next couple of steps... But step by step.

Did you make your way to hexrod? Do you need help?

This goes for anyone. (Jerry Foster)

I got ahead of myself for people new to this. 

What the Stress graphs show is the internal stress of a rod with a given amount of power in the form of 4 G's of acceleration and a resistive load of the length line to be cast. (Line fished). Plus, some other variable that aren't that important at the moment. 

The resultant stress in inch 0z2 results in making the rod bend. So the chart, as I will show later, is also a deflection graph. Now for the sake of argument, my contention is that the shaft bending is what you feel when you cast. Or the rod foreshortening, getting shorter as it bends relative to your hand. Individual rod preference is derived from what you feel, feedback, when you cast a rod. So this chart will eventually, I hope, let you discern the rods you like, or may not like, from the picture you see of the rod deflection profile. It is also useful in rod design by the same criteria. 

So, we have this tapered bamboo stick with some line hanging off the tip that I am going to set in motion. What I feel will determine whether I like the rod or not. I my parlance, whether the rod likes you or not. This is all determined by your unique casting style. There are very few really bad tapers, so the idea is to match the rod/rods you like to their graphs. This gives you a visualization of what you like and you don't have to just ponder the numbers (taper).

Is that a good start? (Jerry Foster)

Trying to read and digest 39 emails on this subject is what has kept me from jumping in sooner. I am still rather new to this. Rod #1 was completed 1/2010; rod #30 is waiting for polishing. I use Larry Tusoni's Designer program and am very reliant on stress curves to come up with a design I want to build. Until reading these recent emails I assumed that the "bumps" in a "famous" maker's taper was due to measuring or production errors but someone, I believe it was Rob Smith, said that some of these bumps were intentionally made for a specific effect. Then I looked at the stress curve of Bob Nunley's much discussed rod and knew that these bumps were intentional because the taper came from designer and not someone trying to measure another's finished rod. So I am trying to get a better understanding of their purpose. The first 15" of this rod are rather thick but the delta between stations drops significantly from .022 to .012 at stn 20 and 25 then jumps back to .020. My initial thought is that the first 15" are stiffer than usual to help keep the loop tight and that the drop in deltas provides a cushion so that the tippet doesn't break on a hard strike. Any comments would be welcome. (JW Healy)

BTW - I now know the answer. The rod in question is Nunley's Snake Rod. The taper was published on the List. I spoke to Nunley at 2013 SRG and he said that he wanted a rod that would be good for very short casts with a gentle stroke and good for longer casts with a full casting stroke. The hinge at 20" is for the short casts. It allows the rod to flex primarily in the top 20 inches. With a full stroke the rod flexes much like a parabolic taper.  (JW Healy)

Yeah, I struggle mightily with the bumps too, especially as I can never get their originaters to explain them in a way I can accept. remarks like "Well, it works”, or "It seemed to make a difference" and other such inquantifiable observations have no place in the design of anything.

Action lengths, well, yes, normally and in most good rods the action should start at the top of the handle, lower down is a bit eccentric, although, of course, if you stress any rod enough you will create a bend under the corks, albeit not much of one. The weazel in the rabbit warren is the rods whose action starts significantly above the handle, sometimes by several feet. This is what Ritz was after by the rods named parabolic, and may I say again that its just a trade name, likeSuperfast, and just as misleading. Unfortunately, Ritz was a hotelier and not a rod designer and neither, on the evidence of my eyes was Pierre Plantet, the rod designer for Pezon et Michel.Perhaps he just decided on the ring spacing. the fundamental error was made because the solution is a bit counter intuitive. Most people, if asked to put the action part of the rod three feet up would create a large diameter, probably untapered butt. It would be a rod on an extension pole they would say, indeed, I’ve heard them say it. their next observation was usually that it did'nt make a very nice rod, they were right! The limitations of the material, in this case cane made the rod heavy and bulky, and P&M took to glass butts for the later rods, with little more sucess. The solution. In fact, is to make a butt as fast tapered as you can, hollow built too. Whatever you do the thing will bend, but its better to have do that up where its bending anyway and not just above the handle, which is what happens on any rod whose tapers are slower than those needed to create a proper quarter circle when bent so the tip is at right angles to the butt. Iam not saying this is the right or wrong taper, its just an illustration.

The trouble is, if you make one of these rods, as I have (I call them "Proper Parabolics.................") they are still not nice rods. They should be, the tip tapers are correct and complete, not truncated like the Ritz ones, by which I mean they haven’t been shortened at the bottom end, but, somehow, you can never seem to get the timing right. They cast adequately with about three line sizes and well with none. It’s not even my opinion that they keep the line especially high or fast either, certainly no more than a fastish rod with a Gould figure of about 340.

If anyone wants to analyse the tapers of this rod and give me their views, I'll break with the habits of a lifetime and put the tapers on public display for you. (Robin Haywood)

My analogy for looking at stress curves is to picture a 7ft long tapered torque wrench. If you pull on it slowly you will feel the points in the taper that a yield the easiest and those that are stiffer. Thats exactly what the stress graph is showing. The problem is of course the casting motion only takes about 1 second so you have to develop a quick sense of feel. But in most cases your overall impression of whether you like it or not is sufficient. You must use, or develop your own judgement protocol.

Robin...

I'm not sure if your making a statement about action length or not, but my point was the rod will bend by the numbers a deeply into the handle as the cane and the force will allow. To arbitrarily truncate the stress curve input distorts stress curve. (Jerry Foster)

Jerry this analogy makes perfect sense to me. Where you place your hand on the wrench will impact the stress points. ie action length. Thanks this helps a bunch. (Ken Weymouth)

I'm afraid you've lost me Jerry, I’m much stupeder than I sound. Would you mind having another go at it please? (Robin Haywood)

Hehee, you can't pull that "Oh woe is me" crap here.. I think you are looking at rods with a developer’s eye, I I'm trying to explain how stress curves work from a post developed rod, analytical viewpoint.

If I really need to elaborate a point...please be specific. (Jerry Foster)

I guess it's time for a note about measured rods and craftsmanship... 

Since Garrison, all rods have been measured on 5" intervals... hopefully with the rod assembled, starting at the tip. Most of the rods we are looking at were made on Mills/bevelers using a taper board, or form. Although typically the numbers on these were set at 3" or 6" they were filed to have a nice smooth surface for the cam follower to ride on. Because the math we use wants to generate a straight line between any two points we will see small zig zags in the stress graph. Most of these are inconsequential. Moreover, most of these rods were measured over varnish and of course not over wraps. So they are close to the originals, but not exact. Does it matter, probably not. 

And speaking of action length, when you change the action length and try to keep the stress constant you will notice that the math tries to predict the numbers for the rod based on the given trajectory. This probably isn't correct, but it is irrelivant. The issue to me is you can never get a really accurate stress graph when the rod has been originally entered with the action length set at the top of the handle. But this is purest crap and doesn't really matter. 

Now in terms of accuracy of your own rodmaking. I always strive for perfection. Never attained, never will, but that is the intent. To this end it takes quite a deviation for more than a single station to create a noticeable difference between that and a rod that is on the numbers. So don't worry about small deviations from the taper. Just try to do better next time.  (Jerry Foster)

Yes, a big THANK YOU to Wayne, for HEXROD, and a lot, lot, more!

Okay, Action Length...the way I always understood it, was Wayne often said that the action of the rod stops at approximately at the top of the grip, so the action length, was about 10" less than the rod length.

However, I've always wondered why that is.  It seems that a cork grip is flexible enough to not dramatically affect the action.

Help!!!!! (Mike Biondo)

I've heard Wayne and others talking about the action is stopped by a swelled butt... Experiment with one. A swell certainly curtails the action but the stresses don't go to 0, so there is still a little bend there. But if you also noticed a lot of the numbers move around when you move the action length which shows the rod doesn't just work in pieces but the overall stress of the rod is impacted (is that a word?). (Jerry Foster)

Jerry, would you please comment on the variable "tip impact multiplier" in the Hexrod design parameters. What is it supposed to capture or emulate? It certainly impacts the dimensions of the design if changed. (Ken Weymouth)

Jerry looking at the stress curves of the granger victory rod, I see an increase in the stress of the rod at 65" created by the minimal increase in dimension of .003 from the prior station. Would this be considered a "hinge". I would have thought so until recent discussions, but now I am not sure but whatever it is called what do you believe its' intended purpose is? (Ken Weymouth)

The stress peak at 65 is a result of a relative reduction in the rate of change at that point.

My guess it is to compensate for the stiffening effect of the ferrule. This happens more slightly at the other ferrule too. I don’t think it would have a hinge effect in that position. (Stephen Dugmore)

It may also have to do with wanting to use a smaller (and lighter) ferrule – probably both (Stephen Dugmore)

Interesting, I will go back and look with a new set of eyes, Thanks Stephen. (Key Weymouth)

Question open to all - What defines a hinge in your mind? And what is its' purpose. I have heard roll casting ability. What other casting attributes would it have?  (Key Weymouth)

Hopefully this question will add to the discussion.  In casting we all strive for a tight loop which requires the tip of the rod to track in a straight line.  It would seem to me that the more the rod deflects the more skillfull a caster would need to be to maintain that straight tip movement.  Stiffer rods would bend less and perhaps would be easier to cast. Parabolics would probably have a sweet spot depending on how close to the tip the "hinge" is but to really load would require some adjustment in the casting stroke.  Does this logic hold any water or does it help to explain why you personally might like one taper over another?  (Ron Kubica)

In my mind, a hinge is a point on a rod where the rate of change in the taper (the delta between stations) decreases and then increases sufficiently to create a flex point so that the rod will bend there more than above or below that point. Cattanach put that point about 2/3 down from the tip to improve the rod's roll casting and that works very well. I am not sure what putting a hinge anywhere else will do to improve the rod and hope someone else can explain.  (JW Healy)

It will make the roll casting easier, I grant you, but at serious cost to the rods other functions.

Also, how difficult is roll casting anyway?

And when it is its for short range fishing, so chop the taper off a line one or two grades higher and use that. It even works better, as the end floats better, being thicker. (Robin Haywood)

OK. Pls help me understand - what other functions of the rod are going to be impaired? (JW Healy)

Back to the tapers subject, again

I have been revisiting some of the older books on bamboo rodmaking, (trying to put my taper collection to smarts). I've been poring over the taper numbers from them. It strikes me as odd that some things have changed, and others not. Our current 'standard' of stating a taper is on 5 inch centers listed continuously from 0 to the rod length (tip to butt), or perhaps split into a table with a butt section column (numbered 0 to length) and a tip section column (numbered 0 to length).

For example, I am reworking Kreider's tapers for my study and no matter what I do I get this nagging idea in my head I'm doing it wrong. He lists numbers at a station of "End" and also one labeled "Ferrule". (sigh, having one set of items that I don't get isn't unusual for me) But throw that in with the fact that he's numbered them in reverse order (tiptop is at 54" for example) and that he is working from 6 inch centers, and uneven numbers of stations, kind of throws me. I can deal with switching to 5" centers. I can reverse the numbering direction, but I keep getting snagged at the "end" and "ferrule". I know what they mean, but how do they relate to the 6 inch stations nearby? An inch away, 4.3 inches away? Other random spots based on where the forms lay there with the taper set?

Particularly since there doesn't always seem to be the same quantity of numbers for each (I don't think they are for uneven length sections, though). Do I simply repeat as many butt end numbers as I need to fill in? Here is an example of what I mean. (I hope they line up right here. The first number in the butt section line is .400 at the 12" station, two blank before it. And the first number in the tip section is at the 'end' station with a blank at the ferrule station) There are nine numbers for the butt section, one for the 'ferrule' (60"?) and 10 numbers for the tip section, one being 'end' (0?). Kreider also doesn't seem to indicate the expected line weight. (I know, I know, they were not so concerned about it as we are now. But I can't yet look at the numbers and guess.)

9 foot, 2 piece
No. 1 By E. C. Powell Rod Company.
          End   6"     12"    18"    24"   30"    36"    42"   48"   54"   Ferrule
Butt                    .400  .365  .345  .320  .300  .275  .255  .240  .234
Tip  .235  .225  .210  .195  .170  .155  .138  .125  .110  .075

Probably someone has already done these conversions and posted them in the taper libraries. But the ones in Kreider aren't well identified that I can pick them out. I end up making assumptions that I start getting uncomfortable about. (But I'm probably ok with those assumptions?)

Someone, please, tell me what is up? Tell me how ridiculously easy it is and what I am stupid enough not to see? (But be nice, throw rocks gently. I have fragile bones. <grin>)

I am finishing up a 3-stringed instrument of cherry and cedar, so I can get back working on a couple 'boo rods. I hope to have my powered mill up and going to handle the roughing and save my back, brain, and, uh, blood, for the tapering with my 9 1/2. I plan on roughing several rods quickly then working the tapers as I go.

Happy in shavings. (Sam Nielson (1/11/2015))

I came up with this spreadsheet a while back that works well. Hope it helps you out.  (Ken Paterson)

There is an oddity with the butt listing because for a 9’ rod, the ferrule should be at 54” regardless of which end your measurements start at.  A graph in Excel shows that the 54” butt measurement is most likely at the ferrule, so on that basis, here is the listing with 6” stations:

0       0.075
6       0.110
12     0.125
18     0.138
24     0.155
30     0.170
36     0.195
42     0.210
48     0.225
54     0.234
54     0.240
60     0.255
66     0.275
72     0.300
78     0.320
84     0.345
90     0.365
96     0.400
102   
108   

Graphically matching the plot of that to yield 5” stations produces:

0       0.075
5       0.107
10     0.122
15     0.134
20     0.145
25     0.158
30     0.170
35     0.191
40     0.206
45     0.219
50     0.233
55     0.245
60     0.255
65     0.274
70     0.292
75     0.312
80     0.330
85     0.350
90     0.365
95     0.396
100    0.420
105   

I prefer a graphic approach because I can see how the values correspond and can spot oddities like the one I mentioned. (Tim Anderson)

I think you can just enter the numbers (starting with zero) at .075 at six inch intervals all the way back to 108 inches into HexRod and it will convert them to five inch centers for you.

Not sure if this is the answer to your question or not. (Larry Myhre)