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Measuring Tapers

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I was wondering which is the most preferred here on the list in measuring a classic taper:

• from tip to butt in consistent 5" stations a la Garrison
• or from the butt end of each section separately as in the Howell book?

Opinions or experiences would be helpful, and then subtraction the .004 - .006 for varnish.  (Rob Hoffhines)

Every inch at three cross sections.  Some rods, are so "out of round" that the numbers you get will be misleading.  But unless you get lucky and notice that the taper is written on the lip of the bag, such as on many EC Powells, what alternative do you have?  (Chris Lucker)

I prefer tip to butt on the assembled rod. This seems to be more in sync with the software and is simpler for me to plot on graph paper.  (Steve Weiss)

Either way works but I prefer the measurements be taken from the tip of each section separately. That way you get the dimension at the ferrule. Subtract .003-.004" for varnish.  (Marty DeSapio)

I like the best of both worlds.

Measuring an assembled rod from the tip = 0 reduces the need for guessing regarding ferrule dimensions and unequal sections, so it dominates in my opinion.  The more frequent the measurements the better, but 5" is fine for me.

Here is the kicker:  take the time to measure key areas that do not fall on the 5" points.  Key points would be just above and below the ferrule and several measurements just ahead of the cork (to capture any swell).  In each case, proved distance from the tip and the average for the flats.

With that information, there will be little guesswork needed by those trying to interpret your measurements.  (Jerry Madigan)

I'd say that since your planning form is on 5" centers, measuring it at one inch intervals is useless as you can only set it every 5" and the taper is a straight line between each of the 5" points. My feelings is measure from the tip as that is the only non variable starting point being that grips and reel seats can very in length but the tip is always at the very end.  (Patrick Coffey)

Several reasons why recording a cross section dimension three times at every inch along the rod include:

All the mills, hand or power, are on 5 inch centers and it's more trouble than its worth to try to set every inch.  (Patrick Coffey)

My mill is not on 5 inch centers, my Grandfather's mill was not on 5 inch centers.  EC Powell's saw certainly was not on 5 inch centers and his tapers were related on 6 inch centers for the purpose of checking his work only. Heck a B9 taper would have been on a 5 FOOT center!

Your above statement does not take into account the CNC mills in the world -- I know of three, and many of you saw one in development at Corbett Lake .  With CNC it is no more trouble to set the taper at every 0.001".  That is what CNC is for.

I understand that 1 inch settings is not necessary.  I build EC Powell-style rods, mostly, so I build rods with a progressive or regressive curve or straight tapers (or a combination of a straight tapers.)  (Chris Lucker)

Measured from tip to butt in 5" increments as an assembled rod. Then plot the curve. It seems to be an understood standard method used by most rod builders.  (Ray Gould)

I had a question with regard to taking a taper from an impregnated rod.  I know that impregnation should not add to the overall dimension of the rod, but I could not help but notice that the impregnation process makes the rod surface look semi gloss.  Should I subtract a thousandths or two or just go with the dims I get from measuring.  (Robert Cristant)

To me, the taper is the taper regardless of  finish or impregnation. I wipe the snot out of the rods at short hourly intervals when they are pulled out of the impregnation tube, and I remove anything that is seeping out of the blank. I would say that the impregnated finish is negligible dimension wise. Most of the surface that is left is buffed off and makes the actual blank surface somewhat glossy.  (Bob Maulucci)

What's a good rule of thumb for subtracting the thickness of the varnish when mic'ing a finished rod?  (Bob Murphy)

Subtract .004" for a normal coat -  .006" if it looks really thick - .002" if really thin. This is for two flats.  (Tom Bowden)

I have just been given the chance to measure a Granger Colorado Special and I was wondering how one goes about estimating the deduction for varnish.  I've refinished this rod at least once in the past but even though I applied the current finish it was years ago and I have no recollection of how many coats were used or even how much you would deduct for each coat if that's the secret.  I will gladly share the measurements if anyone is interested as I have not seen them recorded anywhere in print or on line.  The rod casts like a dream and may just be the best casting Granger out there.  Any advice would be greatly appreciated.  (Bill Ernst)

Below is how varnish was subtracted for online Hexrod:

"Sometimes the source estimated the varnish thickness. If so I subtracted that amount. Sometimes the source says "unvarnished". But sometimes the source says nothing about the varnish. I tried to make a guess whether the measurements are from a varnished rod or not. If so, I subtracted 0.005 inch as a compromise. Some rods were impregnated so I subtracted no varnish, unless they were impregnated and varnished."  (Doug Easton)

Thank you for that information.  Would that be 0.005 inch deducted from the flat to flat average at each station or would it be deducted from half the measurement?  (Bill Ernst)

Yes, it is from flat to flat.  My guess is that .01 would be a whole line weight and a risky proposition. Sometimes an old rod will have been over coated .by a previous owner, then I would edge to about .007. I also plug the measurements into online Hexrod and have it do the subtraction. Then I look at the stress graph with the line length set at 30 ft and the line weight the same as the original rod worked best with. I want to see if it looks reasonable relative to the graphs for similar tapers in the library. If the stresses look to be too high say, more than 350 Mpsi at the tip, I would go down a thousandth or so.  (Doug Easton)

There are a lot of rodmakers on the list making rods and I have suggested this once before so here we go again.

When you make a rod section, pick a couple of points to measure prior to and after varnishing.  Let the list know what results including number of coats, product and method.  Or send the info to me and I will accumulate it over time and publish the results.

I have heard ranges from .001 to .007.  Might be helpful to have a little more info.  (Ralph Tuttle)

I think you may have meant to use 50 feet not 30 feet to get your maximum stress values. For me the Garrisons values of less than 220,000 are only good for the 50 foot length.   (Bob Norwood)

Yes, a brain f#!t, Sorry. On second thought, you need to compare rods with similar tapers and line weights to get a best estimate.

As far as measuring different coatings and numbers of coats etc goes I am not sure how valuable that is for old rods because we don't have those variables available.  (Doug Easton)

When measuring rods should one weight the average in favor of the measurement across the guide flat?  The material in this plane certainly has more effect on the action than the material in the planes to the left or right of the guides.   (Dennis Bertram)

I would assume that the flat to flat measurement on the guides should be given more "weight" per unit than the other two measurements. but I certainly can't put a number or ratio on that assumption.  Jerry Drake could probably come up with a formula to calculate the amount.  He likes those mind-twisters. :>) I'm sure the calculations would be a lot simpler in a quad than the hex configuration. Come to think of it the calcs have probably already been done for the quad.  Probably just Beam calcs.  You could probably associate the non-guide flat dimensions to a percentage of the cross sectional area of the wide dimension of a rectangle in the beam calcs as an approximation.

Gettin' kinda nit-picky for a Sunday morning aren't we ?  (Larry Swearingen)

An interesting question.  I'd say 'no', though.  I don't think the variations in flat-to-flat measurements were/are deliberate, but rather an accident of gluing and binding.  I know my choice of which flat to turn up has more to do with the spacing of the nodes than anything else.  On my top and bottom strips, I want the distance from the tip top and from the ferrule to the first node to be as great as possible.

There's no scientific basis for that, it just seems like a good practice to me.  (Paul Gruver)

I don’t know the ‘correct’ answer but I have thought about it.  I have mic’d a few rods and there can be significant variance flat to flat.  I keep all of the measurements and then can either use an average value or use a weighted average using the differences from the average.   The thought process was to use the two closest measurements assuming the maker screwed up planing one spline.  Can’t say it’s better than any other method, just my way.  (Ralph Tuttle)

I haven't seen any gaping glue lines in Ralph's PHY rods that I've taken the taper off. This is in spite of the numbers being all over the map at times. What did he do different? If I were to glue up a rod that wound up as an oval in cross section I would expect to see glue lines. I know bamboo has some flex and numbers don't have to be spot on, from flat-to-flat. But, some of what I've seen really has me scratching my head, now that I think about it. (Bill Walters (9/10/2016))

I'd guess the strips aren't the same measurements.  It's easy to be a few though off and not affect the final taper, and glue lines may not appear.   (I think most glue lines are caused by "rounding" of the strip edges rather than gaps in the strips.) (Terry Kirkpatrick)

One more thing to consider is his strips were cut at 61.5 degrees, not 60 degrees like on planing forms to avoid glue lines altogether. It would have to be really off for glue lines. (Scott Bearden)