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Form Setup - Test Strips

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Is there another way to set your forms gap other than using a depth gage?  Depth gage is not on the Santa delivery list. But some other goodies are, hopefully will start my first rod soon.  (Pete Van Schaack)

Another way to make accurate rods without the use of a depth gauge is by using test strips. Start by closing your forms completely, then plane out 6 strips, just as though you were making a rod. Be sure the strips have a true 60 degree angle. After completing the planing of the strips, tightly tape them together so you can measure the blank from flat to flat. When you measure a spot that is, say .100 across the flats, then you strip is .050  You can measure the blank every 2 inches and mark them accordingly. Then cut and identify the measured pieces into 2 inch size and you'll have accurate little strips. Then you can use the pieces to later adjust your forms by putting the piece you need into your form and adjusting as needed. Use a straight edge over the test strip and when it will slide over the strip, you've got it.   I received this info from Frank Armbruster, owner of Colorado Bootstrap. When I bought my forms from Frank, he included a pamphlet explaining this very topic.  (Jim Bureau)

Yes, there is.  Some would argue that a far more accurate method of setting forms involves using drill rods, dial calipers, and a little mathematics.  I think there is an excellent description on one of the list contributors web sites -- perhaps Chris Bogart's site??  (Harry Boyd) 

PS - A dial indicator with a 60 degree point can be fashioned inexpensively enough.  Total cost should be less than $35 even if you buy the base from Enco.

That raises (at least for me) an interesting question:  Given the variability in the size, number and density of  "power fibers," are we kidding ourselves with the need for 0.001" (0.01"?) precision in setting tapers?  (David Smith)

I would argue that: No, the variability naturally present in bamboo necessitates precision rather than allowing us some room for imprecise measurements.  Only a limited number of controllable variables exist while making rods.  Accurate measurements make it possible for one less problem to rear its ugly head.  (Harry Boyd)

But logically wouldn't be more prudent to increase the thickness of the rod in relation to the lessening of power fibers from one culm to the next. this same question has entered my brain from time to time, I know as a luthier one increase the thickness of the top and back (bending and flexing) parts of instruments in relation to the grain (power fiber) in spruce and maple.  (Patrick Coffey)

I have to concur with Harry.  We are already working with a relatively variable material so precision in OUR process becomes even more necessary to maintain a constant product.  No, we won't be able to obtain "perfect" repeatability in performance from rod to rod, probably not even if they're made from the same harvest of culm or even the same culm, because of the variance of the properties of the cane.  We can, however, obtain a "relative" repeatability, but only if we have a dimensional standard and stick to it.  In other words, it's more likely that we can build group of 7' 5wt rods that are very close to the same performance if we do hold a tight tolerance than it is if we said, "Ahhhhh, What's a couple or three thousandths here and there?"  (Bob Nunley)

But isn't that what the old guys did and why the same model of rod, from lets say Leonard, have different thicknesses. Didn't they compensate for the lack of or the excess power fiber so that the rods would have pretty much the same action?  (Patrick Coffey)

I understand your point and I use 0.001" measure on my Morgan Hand Mill.  What I wonder about is, given the extraordinary variation in bamboo, does this make a difference?  I imagine that, if power fibers are the issue, tapers should actually be specified in "number of power fibers deep/wide" to be "precise."  This is a armagnac and fire-type discussion.  (David Smith)

I understand your point about power fiber density, and that's one reason that only between 30% and 40% of the cane I buy is used to make rods.  The rest goes to a furniture guy here in town who loves it, or to a monthly bonfire I have out back.   First, I cull by outer appearance, then I have my own standard for fiber density.  If a culm doesn't have the "pack" I like, then it gets sent over to the furniture shop.  This is one of the "musts" that we have in place to insure consistency in performance.  It goes hand in hand with our set tolerances.  Making rods with drastically different fiber densities would be like making a machine and not using the same grade metal every time.  Nothing is perfect, and granted, choosing fiber pack by eye is not the most precise method in the world, but it does make a difference.  (Bob Nunley)

This is a great topic for further discussion because I find it difficult as an inexperienced maker to know exactly what to look for in a culm. I've seen culms with tightly packed small fibers. I've seen culms with tightly packed larger fibers. I've seen culms with less tight patterns, but still having a good concentration of fibers near the enamel in the area that would be used in all but the largest strips. These  fibers,  too,  varied  in  size,  even  in the well-packed areas. I've seen small culms with very tightly packed very small fibers - are these better for tips/mids than a larger culm with tightly packed larger fibers? So it's not always obvious what a real master would consider the best culms, or even the extent to which a real master picks different culms for different purposes.

Something that would be very helpful to us inexperienced  rodmakers  would be  a series of well-lit photos of culms along with your opinion on the usability of each (in terms of the fibers, not surface blemishes which are easy enough to deal with). I'd like to see great ones, poor ones, and everything in between. The really terrible ones would be just as educational as the best ones. I'd like to see the good and the bad in large diameter and smaller diameter culms. Then I'd like to see what others say about it - which ones would they accept? (I'm assuming here that you make these judgments by looking at the fibers showing on the cut ends of the culms, but if not, we'd need photos of whatever you do look at.) I know this would be some work for someone, but it would be a great help. I've seen the 2 or 3 photos (usually poor ones) in some of the books, but I'm talking about a larger number that would help us really understand what you look for.  (Barry Kling)

If one is judicious in selecting his culms, there will still be some variation, but it will  not be anything like "extraordinary."  Beyond this, there is nothing we can do to compensate for fiber density in a knowledgeable way.  All we can do is to build with as much precision as our talents and equipment will allow.

The moment one says to himself; "What the heck, a few thousandths here or there in my planing can't be all that important!" you will only be adding to (rather than "forgiving") the inequalities that exist among different culms.  (Bill Harms)

Except, perhaps, laminate 0.070" of bamboo to Port Orford Cedar to help standardize the material.   (Chris Lucker)

Of course we are kidding ourselves, old timers used to shoot for 1/64"  (.015").  (Tom Ausfeld)

True, but then again, why do we, as rodmakers, and other fishers and collectors of cane say that "WE" are making better bamboo rods than have ever been made?  My opinion is because we do have tools, instruments and knowledge that make it possible for us to make more precision fishing rods. Notice that a lot of the "old timers" didn't put a line weight on their rods?  Reason "may" have been that with a 1/64th tolerance that they had NO IDEA what they were going to turn out.  BUT, measure SOME of the Old Timers rods,  like Lyle Dickerson, Payne, Gillum, and you'll find that not only are their tolerances just as tight as ours, but in some cases, like Dickerson, I've seen rods that were DEAD ON, not only in dimension from flat to flat, but from station to station in like rods.  The "Masters" among the old timers did NOT settle for a 1/64th tolerance, they were definitely sticklers for consistent rods

Still, going back to an earlier response of mine on this subject, we, as a group, tend to use a much higher percentage of cane that the "old timers" and some of the contemporary master makers.  Ask Glenn Brackett what his cull rate is.  Ask Bob Summers.  Ask Ron Kusse. Ask T&T, Orvis and even Partridge!  I believe, in most cases, you'll find that none of these use more than about half of the cane they buy, and some of them consider 30-35% usable cane to be a good average.  I know more than one who has sent back or thrown out entire bales because they did not meet their set standards.  I know one that hasn't even started production yet (but will soon and has been in the business in the past) that has a varmit fence off of his back deck made of bamboo that a lot of people would be happy to make rods from.  Jerry M. saw the fence, and heard me threaten to sneak back at night and steal it! The "old timers" and "masters" were not near as tolerant of variations in power fiber density or outer appearance of the cane as "most" rodmakers are today.  I know a few guys that use almost every culm they buy.  Then again, I had a phone conversation the other day with someone that's very respected in the rodmaking world where we discussed how nice it would be if we could buy a bale where even half of them met our standards...

Patrick Coffey points out in an email I received in the same batch as yours, that in the luthier industry, thickness in soundboards and backs on instruments are changed according to grain of the wood.  When you buy a good aged spruce soundboard and highly flamed maple back for a violin, you could pay as much for those two pieces of wood as many charge for a custom fly rod... that's the wood alone!  In that case, it's prudent to adjust dimension to the material.  In our case, a bale of cane, delivered, shipping and all, cost about $24 a culm (going by an invoice I just paid to Demarest this morning).  We can afford to cull the material to get as consistent a material, and therefore as consistent a product, as possible.  If we do this properly, then dimension should remain the same, and the tolerance we build buy should remain as tight as is possible to maintain that consistent product.  I'm sure Patrick will agree with me on this  (both of us  having experience in making violins), if I could find a stack of 20 soundboards that ALL had 21 grains per inch, I wouldn't adjust the graduation (somewhat same as a rod taper) of a soundboard from violin to violin... and if I could find a bale of bamboo where the power fiber density was the same throughout, I'd never throw away or burn a single stick of cane.  (Bob Nunley)

I agree with all you say, I adhere to the .001" spec myself.  But... With the variability of cane, .001" is probably overkill.  It is prudent to strive for the tightest reasonably achievable tolerance in order to keep variance to a minimum, and I think .001" is not that difficult to obtain. If I were to say that I plane my rods to within .0005",  would mine be better??  More precise, maybe, could you tell the difference casting, I suspect not. I'll go out on a limb here,  I think variation between two rods is more of a function of cane and its treatment than dimensions,  assuming a reasonable tolerance of say .005".

My point was of the original post was:  if you are having problems achieving .001", don't abandon rod making, perfectly good rods can be  built with much less tolerance, and they will just as good as anybody’s if they cast nice.  Just don't bank on making a twin.  (Tom Ausfeld)

A few statements were made that needs clearing up. The old timers didn't  measure their sticks as you and I would today. They measured the ferrule station when they first set up to run a certain model rod. Their steel patterns were measured in  256th of an inch. We need to remember that they used a steel or wood pattern which controlled the accuracy of their strips.

Leonard claimed to cut strips that were within .001" of each other.  (Hal Bacon)

Most of the professional makers you mentioned also saw their strips from the culm.  The rejection rate is particularly high among those makers because of the need to avoid culms that threaten to yield grain runout.  For those of us who are hand-splitting, that issue wouldn't enter in.  In the 1970s I received a huge number of culms from Orvis for exactly that reason --  culms that were, otherwise, just great.

Additionally, makers of "blond" rods would be wary of culms that show signs of watermarks or other stains, whereas for those of us who flame our rods, such cosmetic imperfections are likely to be unimportant.  So, again, the rejection rate will vary accordingly.

This isn't to argue against your advice that we should cull our supplies more carefully, but only to point out that the extremely high professional rejection rate is created by additional factors beyond power fiber density. A good visual examination of each culm is the first thing, followed by judicious "hefting" of many culms for a comparison test.  Greater weight usually equals greater density.

Lastly, upon splitting-out each and every culm, a sample strip needs to be severely flex-tested between each node, Those who are not accustomed to doing this last test may be in for quite a shock.  You will be surprised how many otherwise good-looking culms have an unexpected weak area between a set of nodes.  (Bill Harms)