Bamboo Tips - Tips Area
Rod Design - Taper Variations

< Home < Tips Area < Rod Design < Taper Variations


You know it's funny but I haven't heard much discussion about actual tapers for quite a while. So, I thought I would ask a question that I have not been able to solve short of building the tapers and it might just have to come to that.

I have listed two tapers here, they are the Garrison 193 for ease of understanding; actually they both the same taper with a little twist on the second version. My question is; do you think these tapers will feel and cast the same or because of the slight changes in the taper station numbers of the  second one,  will it be different ? I have my idea but I would like to hear what others have to say.

Here are the tapers.

Garrison 193            Garrison 193 Mod

1       63                       63
5       70                       70
10     90                       95
15    106                    101
20    119                    124
25    132                    127
30    144                    149
35    156                    151
40    168                    173
45    181                    176
50    193                    198
55    206                    201
60    219                    224
65    233                    229
70    270                    270
75    270                    270
80    270                    270

The only thing I have done is sequenced the station numbers for #2 by added or subtracted 5 thousandths making the taper Zig Zag.  The Bamboo weight is the same for both tapers. What do you think?  The same or different and WHY?  (Bob Norwood)

    I think they will definitely feel different, more so if made from the same culm. You've taken a basically straight (OK, shoot me, progressive) taper and made it into one with a series of fast and slow spots, shoulders followed by hinges if you will. At first glance it looks horrible, but it could be interesting to build to see what it actually casts like. If you build it, please let us know what it's like.  (John Channer)

    Just walking back to the shop I also thought that when it comes to questions about feel, it’s important to remember that like sight and sound, everybody is different. Everyone has developed those senses quite differently. I would like to believe that for me Feel or Touch is a much more sensitive than say my sight (I’m extremely nearsighted).  (Ren Monllor)

    Garrison 193 Mod

    I charted the taper, and as you know, a snake would break it's back trying to follow the line. I can see that volume of cane, weight, and weight distribution should average out the same. So I accept that it would likely deflect the same as the original. But would not all those hills and valleys possibly be a source for secondary vibrations? Could a taper like this transfer power from the caster to the line as effectively as something smoother?

    It would seem counterintuitive. Not that I can prove any of that, but it is an interesting mental exercise, Bob.  (Tom Smithwick)

    After looking at the tapers I'd like to add that I think the difference would be significant ( to me anyway). One rod has a turnover point at 5" the other is further back. I think I'd be able to feel this change when cast 10 - 20 feet of line. With Jerry's rods I found that 5" wasn't to my liking.  (Jim Lowe)

    Your forms are going to cry when you set them for the MOD!

    My deflection program says they should feel identical.  If you build them and find they are the same, it goes to prove what I’ve thought: a few thousandths tweak here or there is averaged out and hardly matters.  You need to make significant overall changes to make a big change in feel.  Of course,  smaller changes at a tip are more significant.  (Al Baldauski)

      I see you were up late last night and figured you’d wake us up a bit…..

      My thoughts…I think that it would be close in feel, but not identical.  I believe that with all the hinges built in, at the point you begin to muscle in the cast, there’s going to be a difference felt only because you’re casting what vaguely resembles the links on a chain.

      On a more effortless cast you probably won’t be kicking in the hinges.

      I know my terminology is awful compared to an engineers, but please bear with me. I also do believe that if the difference from station to station isn’t tooooo great, it will all average out.  (Ren Monllor)

      I've long felt (with no proof or justification) that it takes a pretty significant change to make a difference that the average caster can describe. Not just feel, but actually put a description too beyond the usual 'faster, slower'. In this case, I can't help but think that one or more of those hinges will work at a given load, and change the feel. How significantly it might change is another matter, of course.  (Larry Blan)

      I agree with Al. My program also indicates the same deflection.

      I reckon there will be very little difference in the feel, if any. It is an interesting exercise, especially given the different stress diagrams the tapers generate – although the overall shape of the graphs are similar, the peaks and troughs of the hinges/shoulders obviously register quite differently in the snaky one .

      Of interest is that the ‘snaky’ taper does have a higher maximum stress (at the 20” mark) than the ‘smoother’ one. This may result in a slightly different feel, but I doubt it.  (Stephen Dugmore)

        If you all ever get the chance to cast Jerry Foster's experiment series, you should.  He had them at the Metolius Bamboo Rod Fair in Camp Sherman, OR, this past July, and I expect he'll have them there again this coming July.

        He made a series of rods, starting with the same taper (8' 5 wt, .013/5" or so), and then using Max Satoh's program (dynamic deflection) built one series with the maximum stresses of 180k, 200k, and 220k; a second series where the peak stress (180k) was at 10", one at 15", one at 20", and a third arm where the length of the peak varied (IE. a flat stress curve, which deviates upward only over 5", over 10", over 15", over 20", I think they were).

        The bottom line is that YOU CAN feel the difference between the rods, though some differences are very subtle.

        Also, as a tool, you can "test fit" a customer to figure out what that individual likes best and "customize" the rod to them.  (Chris Obuchowski)

          Having cast Jerry's rods, I would have to agree. Some of the changes were subtle but you could feel the differences when cast side by side. If one rod has a different maximum stress (as Jerry's did) you can definitely feel that.

          I think if one rod has a bunch of hinges, you'd be able to feel that as you progressively stress the rod when you test your loop control at different line lengths.   (Jim Lowe)

            I think Jerry’s experiment is a different kettle of fish to Bob’s. Significantly changing the maximum stress and/or shifting the location/extent  of it would have to make a difference. Bob’s experiment doesn’t quite do that. Although there is a slight difference in maximum stress I don’t think that is the point of Bob’s question. I am sure he could tweak the taper to make the high point stress the same and the question would remain. I get the feeling that the shoulders in Bob’s experiment might well provide enough support to the hinges, effectively smoothing the whole thing out.  (Stephen Dugmore)

              I would say that by introducing the hinges, you effectively change the position of the turnover point or spread that point over a range which would have a different feel.

              A good caster can make a rod bend just about anywhere they want. I've got to imagine that having several soft spots in the rod is going to be felt. Especially in the tip.  (Jim Lowe)

    Well, I had a few replies about my question regarding these two similar taper. I realize this is not a scraper but, in my thoughts a rod taper is almost as important as a scraper.

    I'll try and summarize the answers I got as I understand them:

    • Some said you would feel every point flex where the taper went from a large change to a small one, sometimes we refer to this as a flex point.
    • Some said that the two tapers will feel the same, since the zig zag ones weight will average out to be same as the smooth one.
    • Some said that it takes larger changes over a number of stations to make anything really be felt.
    • Some said that they thought that at some line length one or more of the low points, of flex points will be felt, a line-rod thing.
    • Some wondered about the transfer of power down the rod, on this, I would offer up all the rod tapers which have changes similar to this, some of the more famous ones.
    • And a lot of folks said NOTHING, it's hard to believe that there aren't more maker with opinions on tapers.

One point that was not mentioned was that the ZZ outside taper length is longer than the smooth one, which could mean that the ZZ actually has more power  fibers thus it's a stronger rod, maybe. I'm just putting this out as something as something to think about.

Steve Dugmore asked me what my thoughts are.

Well I have the undocumented feeling that offsetting changes like these are actually averaged out by the power fibers, since they are much longer than the 5 inch stations changes. I have see many tapers that have one or more changes like this and wondered what the designer had in mind when he was doing this and if these were actually making a difference, maybe someone who has done designs like this would share their thoughts with us. I also feel that, if we just averaged the taper over these areas that no one could tell the difference between the rods. I have no proof of this, just the many hours looking at rod taper deflections and trying to see taper changes I had built into the rods. In my experience, I have great difficulty seeing any taper change that  is shorter  that 15"  and  the  change  no  more than .005. The way that I look at tapers and lines is that a good rod should handle three line sizes, thus small changes are just that, and have little influence on the rod.

If I get the chance to build one of each I will let you know what I find out.  (Bob Norwood)

      I would be interested to hear. I probably spent too much time with QC guys over the years, but I would suggest that since you are cycling .005 over and under a baseline, that the variance you are dealing with is .010, not .005. I think it was Steve who pointed out that there is a stress peak at the 20" mark. That would make me a bit uneasy, as I suspect that is a critical area, My guess is that that would maybe produce a tailing loop if the rod was really loaded up, but I suppose that's a question of degree.  (Tom Smithwick)

        You are right about the .010 between stations but it's only .005 between the center line and I still feel that the bamboo fibers will average the stress out. I have seen too many tapers with sharp stress peaks like these to feel that they really get to values that are anything like the graphing shows. Look at Waynes 6322 and 6032; Dickerson's 8062; Doug Easton's 9063 Quad and Gallus 9083, these are all examples of sharp changes. 

        I think I have a Garrison 212 in the shop if I do, I will make a 212 taper with the zig zag and we will try it out. I really don't know and I would like to.  (Bob Norwood)

          A 5 thousandths deviation is a 5% change at station ten and 2% at station 65 producing an average of 3%.  Change the taper scenario slightly making 5% adjustments instead of 5 thousandths.  I believe the rod will favor the weakest links if the offsetting adjustments are proportional.  You can see that in the deflection chart at the following photo.  The chart also includes a 10% scenario.

          Bolin, David 193

          I do not believe an inverse adjustment is enough to fully offset the weak point created by the hinge.  (David Bolin)

      Rods don't cast tailing loops, people cast tailing loops.  (Reed Guice)

I built the two tips for a Garrison 212 and it was just as I thought, I can't tell the difference in casting or on static deflection on the wall. My feeling is that bamboo is such a forgiving material that it just shares the load on either taper.  (Bob Norwood)


Site Design by: Talsma Web Creations

Tips Home - What's New - Tips - Articles - Tutorials - Contraptions - Contributors - Search Site - Contact Us - Taper Archives
Christmas Missives - Chat Room - Photo Galleries - Line Conversions - The Journey - Extreme Rodmaking - Rodmaker's Pictures - Donate - Store