Bamboo Tips - Tips Area
Form Setup - Taper Reading

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I'm about to set my forms for final planing, and I find myself in need of a little advice. 8 1/2' rod, the taper I have goes from 1" to 90". .363 at 90", should I assume .375 the rest of the way out? Also it shows .239 at 55", how can I figure 51"? (Bill Freiman)

First, I would assume that the taper beyond 90" either stays at .363" or only slightly increases.  Should you choose to take the forms to .375" at the 95", 100", and 105" stations, that will work quite well.

Rather than trying to figure what the taper is at 51", just be sure to set the forms at .239" at the 55" station; then set the 50" station at the correct measurement.  That's as close as you can come with forms on 5" centers.  Still, if for curiosity's sake you want to know what the 51" station is, you can easily extrapolate that number:

    .239" (55" station)
    -         (Minus)
    .2**    (50" station)
    .0**/5 (divide result by 5)  Difference per inch

Add the difference per inch to the 50" measurement, and you've got the 51" dimension.  (Harry Boyd)

Is the 90" mark the end of the action length? If it is then you will swell the butt up to the 95" mark, then carry the same setting on to 100", 105" marks. Or if the 85" mark is the end of the action length, then it would swell up to the 90" mark then on through the 95", 100", and 105" marks.

I set the entire length of my forms, then start planing the strips at the end of the forms, then work my way up to final position on the forms. Keeps a lot less bamboo sticking up above the forms and makes it much easier to keep the plane level to the forms. Rock the plane from side to side and you can feel the center or balance. You can't do this when there is a lot of cane sticking up above the forms. Since the 55" station is already set, extend the tip strips past the 50" to the 51" mark, plus the amount you allow for trim off (1"--1 1/2"). So the end of the tip strips will be at the 52 or the 52 1/2". Ferrule end of the butt section is the opposite. The strips will extend past the 55" mark to the 51" mark, plus the amount you plan to trim off. If you allow 1" trim off, then the butt strips will begin at the 50" mark. Then 50" station needs to be set also.

Now if you are using step ferrules, then you have to calculate a new 55" dimension for the tip strips and a new 50" dimension for the butt strips. You can get these from the dimension/taper graph by extending the lines from each direction on the graph.  (David Dziadosz)

What's the setting at 50"  Once you get that, subtract the setting at 50" from .239", divide by 5, then add that to the measurement at 50"  (Mark Wendt)

I'm working on a 7' #3 Cattanach taper. Problem is that I can't get my forms set that shallow. Station 00 is 0.033" and 05 is 0.034". Now not to sound too stupid but my form has a taper depth of 0.001" per inch of length. The recipe calls for a drop of 0.001" over 5 inches of length.

I can't get my forms to do that. Is there a trick or did I just cut my taper too deep when I built my form? (Lee Orr)

Are you saying that you don't see how that will work or are you saying your forms can not be set to 0.033? If you are saying you can not set the forms to 0.033 then you are correct you can not make a tip that small, but that is a 0.066+ tip and that would include a lot of rods and that is unfortunate. If you are saying you do not understand how this could possibly work out, try this; set you planing form from the tip end first. Hopefully, there will be the slightest gap between the bars at .033. When you set the .034 5 inches away there will be less gap.   (Timothy Troester)

There are a couple of workarounds.  Simplest is to get or build forms with the final station at .025" or smaller.  I built my forms with the final station at .020" on the advice from either Tom Penrose or from Jack Howell's book, don't remember which.  With wood forms, it's relatively easy to plane the top surface down a little thus making the grooves a little more shallow.  Filing that much off of metal forms is asking for trouble with angles.

Next easiest is to free hand scrape a few thousandth's off  the last station or two.  Of course, I would never do that <g>.  (Harry Boyd)

Before I got my metal forms I had a wooden one that was a lot too deep at the shallow end of the tip  side. I took a little 5 minute epoxy and painted the grove and used the 60 degree grooving tool to redo the grove to a smaller depth. It was a last resort effort but it worked.  (Don Anderson)

OK. I can only get my form closed to about 0.032". I have been debating on filing the surface down some.  Guess now is the time to do it. 

This all comes back to the edges of the steel I used when making the form.  The bars edges were slightly rounded off and to get a 60 degree angle the depth had to be at about 0.030".

Would another option be to slide the strips up the form? With some really careful scraping and measuring it seems the same results could be achieved.  (Lee Orr)

I slide splines when I make one piece rods that are longer than the form. This might be a way to attack the specific problem now. (Timothy Troester)

A bit more info to add on my problem.

I am hitting the 0.033" at 00 but I'm 0.034" at 05 or 0.003" over (0.006" total).  I assume that 0.006" is enough to be concerned with affecting action.  (Lee Orr)

Sorry, typo.  I'm at 0.037" instead of 0.034".  (Lee Orr)

Had much the same trouble when I was trying to replicate a rod with a 0.048" tip using a form built for 0.060 [ 1/2 dimension - 0.024 on a form that was 0.030"]. Took a belt sander to the last 15 or so inches of the form. Tapered the form to the required dimensions + 0.002. Draw filed the form to the final dimensions and made the rod. Worked just fine. Appears like your form is a tad over large in the tip.  (Don Anderson)

I'm attempting to set my forms to begin final planing on my first rod. I'm looking over the taper and I'm confused a bit, well actually a lot. I have attached the taper I am looking at, which was pulled off the archives here.

1. At what point does the butt section end and the tip section begin? I believe the butt will end at point 45 & the tip will begin at point 50

2. There are a couple points that do not denominate by 5” points 84 & 96. Do I set the forms to this depth 4 inches past 80 & 1 inch past 95?. If this is the case, will the butt section be 1 inch longer than the tip? Points 84-96 are all the same measurements so maybe it's a moot point anyway.

3. Can anyone tell me what ferrule size I will use (assuming I actually plane correctly and the rod will be worthy of a ferrule instead of a couple popsicle sticks taped on).  (Chris Hei)

Let me take a shot at this...

1.    The rod is 8 feet long, or 96" in length.   The ferrule ends of both the tip and the butt will end at 48".

If your bamboo strips are anything more or less than 2" over length at each end, you will have to adjust the point at which you place the end of the strip in the forms to somewhere other than on one of the stations.  Let me see if I can make that a little less confusing.  Your strips will need to be 48" (1/2 rod length) + a little leeway on each end.  If the strips are 2" over length at each end (or, 52" total) , the big end of the tip will fall very near the 50" station.  The small end of the butt will be at about 46".  (Man, this is easy to show you, but hard to write down)

I always mark my forms with a Sharpie where I want the big end of the strip to sit.  If I then place each strip on that mark, my strips are consistent.

2.   The rod was measured after completion.  Chances are very good that the ferrules, cork, and reel seat prevented it from being measured at certain points.   When planing the butt section, I would set the forms at the 80 inch mark, then use .312 for 85", 90", 95", and 100"

3.   If you have already reduced the taper for varnish and you hit your targets, the 48" point will be .220".   I'd use a size 14 ferrule.  (Harry Boyd)

I’ll try to answer Your questions:

1. The tip starts where the butt ends - simple as that: same measurement.

2. Don't bother with the difference: treat 84 inches as if it were 85 - You won’t feel the difference.

3. Don't buy a ferrule until the rod is glued up and cleaned. If you buy a ferrule first, it won’t fit: Murphy’s law.

Make that rod - it’s the ONLY way to learn the business.  (Carsten Jorgensen)

In the description of a rod, when it says "deduction for varnish .000", does that mean you don't need to deduct for varnish or that no varnish was deducted and one should make a deduction.  (Henry Mitchell)

That's always been a question in my mind. We are left guessing whether those listed with 0.000 deducted had varnish on them or not.  Which leaves an uncertainty of anywhere from 1/2 to 1 full line weight depending on how much varnish was on the rod, if any.  (Al Baldauski)

In looking at the various taper databases some are quite straightforward telling you details of what was subtracted or that  so much needs to be subtracted or that it was measured on a bare blank. In this case I would assume that nothing was subtracted but that leaves you not knowing whether the measurements were made on a varnished rod or not and how heavy the varnish was. I'd rate this right up there with a taper that has no information at all with it. The really frustrating fact is that most of these databases are so intermingled that you can't even compare one to the other to try and get an answer since you're probably just comparing the same tapers. Larry Tusconi has done a great job combining tapers from many databases into RodDNA and has religiously included notes on the varnish question but there are still dozens of them where you just have to guess. When I have a question about a taper I usually compare it to a similar rod taper for dimensions and stresses.  (Larry Puckett)

Everyone has their own estimate as to the amount of varnish on a rod. Sometimes there is more on one section than another. I would not expect that many people owning fine original rods would like to strip them so that they can be measured. I think that let the buyer beware is appropriate in using tapers from the databases. Some say that you get what you pay for and in this case we must depend on the generosity of our friends. Besides, It is fun  to make the best of the available measurements and see what we get. After you make the rod you can decide whether you subtracted the right amount for varnish. :)  (Doug Easton)

Thanks for your thoughts Doug.  I think I deduced that you are involved in original rods so you must restore them.  That being said, I would guess you measure over the varnish before you strip to refinish to get a running average of varnish thickness on the older rods.  If you have done that, do you have a figure you use?  (Al Baldauski)

I wish I had done that, but most of the rods I have had to strip either had horribly blistered varnish or were heavily over coated by a previous owner or restorer so I am not sure that these measurements would be valuable. I think a good experiment, which I am thinking about conducting would be to take a section and varnish it measuring the bare section and after each coat. I think that could be useful, however the way the varnish is applied probably makes a difference. When I get a break around January I will try it. (Doug Easton)

I’ve done that.  Three dip coats of Minwax spar urethane give me about 0.0015 to 0.002 build (total). The NEW Minwax is much less viscous than the old stuff and less than other brands so there can be a BIG difference. (Al Baldauski)

When you say Minwax spar urethane are you referring to Helmsman? That's what I use and have noticed that it is quite thin but I get an excellent finish with it. (Will Price)

That’s it. The finish is very good but I found I had to use a draw rate not exceeding 2 inches per minute instead of the 3 ipm I used on the “old” stuff. Because the viscosity is lower and the draw rate is slower you get less build per pass compare to the “old” variety. Also, it’s less forgiving about very fine particulate on the surface before dipping. With the old varnish I could lay on a coat without any worries about “garbage” in the finish, now I have to be very attentive to wiping the blank with mineral spirits before dipping. The thinner coat doesn’t cover as many sins. (Al Baldauski)

Yep, I agree about it being less forgiving. Not that it matters a whole lot but I use a draw rate of 1" per minute and have found that it helps eliminate the finish from pulling away from the apex.  (Will Price)

I find you are correct. If you draw at 1 to 1.5 inches/minute you can varnish the rod and guides. I was drawing at 3+ inches and stopping at the guides, really a pain, tried the slower speed and found it did a good job with no problems.  (Bob Norwood)

Another way to ask...if a taper is given from a known rod w/o specifying any deduction for varnish, how would you interpret the figures?   Would I then need to subtract? (like maybe .004" total or ??)  Or would I assume the deduction has already been done?  (Jeremy Gubbins)

Usually if someone measures an existing rod they will say to deduct .004 for varnish or if they're refinishing it they'll say it's on an unvarnished rod but over time and as the taper gets passed around some of this information gets lost and this leads to the confusion. And even if it's numbers from an actual taper the chances that your rod is going to be an exact copy is very unlikely. So I say build how you think it should be built and leave at that and don't even worry about the varnish. Who's going to prove you wrong when it's finished anyway. Not me.  (Ken Paterson)

If a number is assigned to allow for the thickness of varnish, is it assumed that the coat is uniform along an individual section? Whether dipping or brushing, does it make a difference if the section is hung tip end up or down while still wet, as the flow will certainly continue? Assuming that the flow evens out and the thickness is the same in either case, then when the varnish has cured, will the taper not be the same whether measured over the varnish or not? The point here is that the taper is the important criteria, and any dimension(s) can be applied to it. If it's a Garrison rod that's being measured, it will be a Garrison taper that being duplicated ~ No?  (Vince Brannick)

I'm sure this question has been asked more than once by a newbie, but I have to ask.  When all is said and done how much difference does the varnish  thickness have on the final rod action?  I've read on this list that some of you subtract as little as, .002" and some as much as .004" for varnish thickness, but if these differences are plug into one of the one of the rod taper programs and the stress curves are compared is there very much difference? I also imagine that rods built from the same taper by the same builder  might  have  different  measurements  by a few .001",  but are the actions of those rods significantly different?  (Tom Key)

When you consider that varnish measurements are corrected  by .002-.006" and a .005" change is equivalent to about 1 line wt then it can make a big difference whether or not you apply the correction. Therefore being incorrect by .001-.003" at any station may make a significant difference. Most of the variations you see in measurements are and order of magnitude smaller -- on the order of .0002-.0003" and likely don't make a big difference. It would be interesting to actually measure a blank at the various stations before and after varnishing to see how much the thickness varies as a result of varnish flowing down the blank as it hangs there. Since a lot of the older rods were sprayed and not dipped then dripping would not be the issue, but there would have been some variation as a result of differences in technique and consistency.  (Larry Puckett)

Garrison tapers weren't measured You get the design numbers directly from "The Book." (Larry Swearingen)

Carmichael wrote in 'The  Book', "we have attempted to provide a cross section of some of the tapers most often requested". Might that suggest other Garrison tapers exist? Might someone loan an aspiring builder a Garrison to copy? Garrison was cited as an example only ~ could have been South Bend, Dickerson, Horrocks Ibbotson, Payne, or any other. The question was about whether the presence of varnish changes the taper.

The matter of the effect of varnish with respect to action is also addressed on pages 186, 187 of 'The Book'.  (Vince Brannick)

I’m going to make the 7’9” Payne from the Howell book, but the taper is backwards from the way I set my forms. Has anyone converted the taper numbers so the larger dimension is at the 50 mark and the smaller dimension is at 0?  (Dave Beerbower)

In the Howell book, for the tip, the 0 measurement is .196 and the 47 setting is .073.

I set mine from right to left, so my 0 would be .073 and going up increments of 5 to 50 at .196.

Of course I have to subtract the varnish and divide by 2. I assumed that the taper between the 5" increments is linear. I hope that explains, but I may have made it more confusing.  (Dave Beerbower)

Set the 45" and the rest of the stations that are multiples of 5 as per the book. Then set the 47" station by setting your indicator 2" past the 45" station, but adjust it my moving the screws of your 50" station. That's the most straightforward way I have been able to come up with. (Henry Mitchell)

My problem is that the 47 station becomes my 0, so 5” increments go to 42 and 37 etc.

I assumed that the taper was linear between stations and then added 3/5 of the difference between stations to the lower number to make it come out evenly at 45 , 40 etc. I felt like I had to do that to make the ferrule stations come out equal. I have attached the final converted taper numbers for your review. I graphed the original against my converted numbers and then skewed the plots and they came out identical, so I think I did it right. Your thoughts are appreciated.

(Dave Beerbower)

I did not explain myself well. as I'm used to working from Howell's book. Make the 45" measurement your 0, and make -2" the true tip of the rod. Set your dial indicator at the -2" location, adjust the -5 station until you get the correct measurement at -2. (Henry Mitchell)