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I want to make a one piece 6 foot rod, and have the numbers for a two piece that I particularly admire. The taper is reasonably complex, but I think I have a basic understanding of why it works. Before resorting to technology, I figured that taking out the ferrule would require the addition of 'more wood' in the center of the rod to simulate the stiffness if the ferrule. Simple. But how much?????, that is the question. I drew graphs and ended up with a dimension graph and taper sheet that looked plausible- all gut feeling stuff though. The problem is I thought I would check it by running it through Hexrod. The stress graph of my 'more wood' guess was quite different to the original two piece, and I couldn't really see why. Next step was to calculate the dimensions from the stress figures of the two piece with the only change being no ferrules. When I calculate the dimensions, I end up with a rod that has no change in the tip dimensions at all, and is a little bit smaller in size in the butt with the reduction increasing as you get closer to the handle. I can not fathom how having a finer, slower butt section can equate to removing a ferrule..... Can anyone rationalize this? Am I asking too much of Hexrod? Is my 'more wood' theory too simple? (Dave Kennedy) After "talking" with Dave, he sent the following: In the meantime, I have finished the rod and fished it for the first time last weekend. As built, it casts a 4 weight beautifully, being powerful enough to reach out to maybe 60 feet with absolute ease. Being so short, it needs a haul to load up the butt for the longer cast or to push into a breeze. I haven't tried a five weight line on it, but I think it would carry one perfectly for shorter ranges. There is a very simple explanation. Hexrod calculates the bending stress on a simple cantilevered beam, not the deflection of that beam under load. This means that the stiffness of the ferrule has nothing to do with Hexrod stress calculations. (It will affect the deflection!) The only loads that Hexrod applies to the beam is the external line weight (as a tip impact factor) and the weight of the rod itself, including the bamboo, the ferrule(s), the varnish, and the guides. By eliminating a ferrule, you reduce the weight of the "beam" and thus would need less bamboo to achieve the same bending stress. Others have found that the bending stress curve from Hexrod, although admittedly inaccurate, gives a good way to approximately duplicate the "feel" of a rod. It is a good place to start. Chapter 14 of Garrison/Carmichael, the Milward book, and a basic engineering strength of materials book would be good references to learn more. (John Sabina) You lead in to another point... what then are the true forces that make the rod bend during a cast, and how can they be evaluated? Garrison estimated for it by using a fudge factor but totally ignores deflection, and the amount of energy actually required to deliver the line/leader/fly from point A to B. Milward alludes to it, and offers a way to evaluate the deflection and bending stresses of a bendform, but does not offer us a method to arrive at the bendform. Montagne claims to have modeled this to divine perfection, and offers a lot of technobabble in his interview with Reed (if you can wade through the narcissism), but does not explain his method in sufficient detail to be able to verify it. Anyone want to take a guess? Would be a fun problem to solve. (Kyle Druey) The main reason for making a one piece rod is because there is no ferrule and the entire rod bends smoothly and usually casts a lot better. Why in the world would you want to add more bamboo to simulate the ferrule? If you are going to put up with the stiff spot as if there was a ferrule, why not put in a ferrule? (Darryl Hayashida) About eight years ago I wrestled with this question too, but as I don't understand Hexrod or any other system that uses physics and math, I simply made a decision and built the damn rod. Like you, I was also working to turn a 6' two-piece into a 6' one-piece. So I thought that, because any ferrule would be bound to function as a "hard spot" in flexing the rod while casting, this would have the effect of sending at least some shock waves back down the butt section and because of that, would interrupt the smooth transfer of power outward to the tip. What that "translated" into, with my line of thinking, was: if I did away with the ferrule, I would not need to build a thicker cross section at that point, since I wanted the bamboo to be able to shed its load, uninterruptedly, right on down the shaft to the tip. I don't know if that reasoning makes sense in terms of physics or not, but it "sounded" good enough to me. Secondly, because a ferrule adds weight at the midpoint, this could only have the effect of slowing the rod's action, and so the butt section of a two-piece rod always needs to have just enough "wood" down its shaft to counter that effect. Get rid of the unwanted weight, and the cane can simply "do its work" without having to overcome any obstruction. So, again, I thought that I wouldn't want to change dimensions at the ferrule station. The conclusion I drew from all this was that if I just left everything in the two-piece taper exactly as it was, and simply built the one-piece version right on through the damn ferrule without changing any of the dimensions (the rod in question had no step-down), I would have both a smoother and a crisper rod than the two-piece version. So that's what I did, and it turned out to be my very favorite rod. Other guys seem to like it too, and I now build nearly twice as many of those puppies as all my other rods put together. You have no idea how a ferrule just kills the action of a rod until you get rid of it and build a one-piecer. It's a real eye-opener. Now, if you are converting a two-piece rod that has a step-down at the ferrule, I imagine the easiest way to deal with that would simply be to measure the amount of the step. Then reduce the dimensions of the last 5" of the butt by half of that measurement, and add the other half to the bottom 5" of the tip. That should smooth the whole transition out nicely. Good luck, and quit worrying about the high-tech stuff. Just BUILD the rod. You'll love it, if the two-piece version was any good to start with. (Bill Harms) Here's some numbers that may help you. I don't have a six foot taper handy, so I used the seven foot Sir D as a two piece 4 wt with 30 feet of 4DT line out the tip top. At the ferrule, the moments that apply are the line in the air and tip top, the line between the tip top and the ferrule, the varnish and guides, the ferrule (zero at this point) and the bamboo. For the aforementioned rod, these moments are, respectively, 49.2, 2.6, 5.5, 0.0, and 22.2. At the grip, roughly station 75, the moments, with the ferrule, are 87.8, 8.4, 17.7, 43.3, and 138.6. The ferrule accounts for 14% of the total moment as seen at station 75. Here's the taper as a two piece: Point 0 0.068 And here's the taper for a one piece that has the same stress curve as the two piece: 1 0.0680 The moments for this rod at station 42 are 49.2, 2.6, 5.5, 0.0, and 22.2. The moments for this rod at station 75 are 87.8, 8.4, 17.7, 0.0, and 134.4. The bamboo has a smaller moment, all in the butt section, because it has less bamboo. Theory says the two rods will cast the same - aside from culm-to-culm differences in power fiber density, etc. (Claude Freaner) Thanks all, I now have a much better understanding of how and why the numbers came out the way they did. I still have an uneasy feeling that the numbers don't quite gel with the real world, but agree they are at least a good place to start. Actually when I look at the differences, I really have to look hard at my planing skills and question if I can really control the end product to that degree of accuracy anyway. Ain't technology wunnerful...(Dave Kennedy) I have no doubt that you can control the accuracy of your hand planing. When I built my first one-piecers, I did not yet have my Morgan Hand Mill, and my planing forms were only five feet in length. I simply set the forms to plane the lower half of the rod first, and then flipped the forms over to "pick up" the dimensions at the transition point into the upper half. You only need to take care that you mark the strips and the forms clearly to retain the "register" for the transition you're after. No problems at all, other than protecting the floppiness of a six-foot strip. (Bill Harms) You're welcome, I'm sure. But take note of today's posting by Claude Freaner, too. His work with math, physics and Hexrod suggests that, upon removing the stiffness and the weight of a ferrule, we also ought to remove "wood" through the lower half of the rod to obtain a rod with identical action to the two-piece version. Math may show that to be true, and you'll also find the resulting rod will be still lighter in the hand when casting than the one-piece version I had proposed. And, of course, you may either like this or not. Secondly, exactly how either Claude's version or mine would feel in comparison the two-piece original is something one would need to try to know. Anyway, I would bet almost anything that you will prefer either of these one-piecers to the two-piece original. Claude's "new" taper for a one-piecer proposes to remove:
I have not tried thinning the one-piecer behind the ferrule, and maybe, in the end, it would only be a matter of what kind of action you like to feel. In any event, Claude's "new" rod would feel different, I am sure, from my way of building it. Certainly, I have no preference in the matter, and I am sure, too, there is no right or wrong way to proceed. Still, it's good to have the math behind the procedure if you can manage to understand it. (Bill Harms)
Since where I live would basically be a desert if left alone, the streams and creeks are very small with the banks overgrown with bushes and small trees. This means a short rod is a lot more convenient to use than a long rod. Over the course of a few years I have been developing a 5 ft. one piece rod. I would like to open a discussion on the steps which lead to the rod I have today, and hopefully I can pick up some ideas to improve it. I guess the first step was deciding on a length. Why 5 feet long? A more common and more acceptable length would be 6 feet. The decision was as simple as that is the length of my planing form, and since I was aiming at making it a one piece, that was the length that was more convenient without having to slip the strips up and down in the form. Why one piece? My reasoning on that was this little rod was already going to have problems with a short action length, so I didn't want to handicap it some more by putting in a 4 inch stiff spot in the middle. I have since changed my opinion on this decision since I have since made a two and three piece version of this rod. The one piece does cast better though. I wanted a fast rod for mostly dry fly fishing, and in a decision that seemed logical at the time, I made it a 2 weight. As it turned out, a stress curve that is a fast rod in longer lengths is way too stiff for a 5 foot rod. My thinking about short action length and eliminating the ferrule should have carried over the shape of the stress curve. I have formed an hypothesis that in an 8 or 9 foot rod the length of the rod on short casts that is bending and springing back - imparting energy to the line - is about 4 or 5 feet. On a 5 ft. rod (trying to mimic the stress curve of a fast 8 or 9 ft. rod) there is only about 2.5 to 3 feet of the rod involved in a short cast. What I needed to do is get more of the rod involved in a short cast. So the stress curve ends up looking like the stress curve of a slow rod. But the action feels more like a fast rod. I believe that is due to the short length (less leverage) and less weight so swinging the rod in a cast is quicker. That got me a rod that was close, but the problem was in the few times a day I wanted to cast 35 or 40 feet the rod was too wimpy to do that without a lot of effort. So how do I use most of the length of the rod in a short cast, but still have power in the butt for longer casts? It took me a while but the idea I came up with is a modified swelled butt. The swell is more gradual and extends 4 inches up the rod from the handle. On a long cast the swell doesn't stop the action, it accepts the bend and contributes power to the cast. Essentially compressing the action of a stiff butt into 4 inches. Another thing the swell does (I think), is it acts like the Cattanach Hinge at the front where the swell starts, since this 5 foot rod roll casts very well. I have been able to roll cast 25 to 30 feet. Which is great for such a short rod, and wonderful in the brushy streams I use this rod in. Since the fish in these streams are small, it would seem logical that this rod should be a 2 or 3 weight. This ended up not being the case though. Most casts in these small streams - I can jump across them in some places - are 10 to 15 feet or shorter. with a long leader sometimes there is only a few feet, sometimes only a few inches of fly line past the tip top. A larger weight line gets more line weight into the cast when there is such a short amount out. But the rod still has to handle the weight of the line when I do want to cast longer distances. I ended up making the rod a 5 weight after going through making a 2 weight and a 3 weight. So that's what I have at the moment. A 5’ one piece 5 wt with a modified swelled butt for small overgrown streams. I have made this rod into a 2 piece and a 3 piece because carrying a one piece rod is difficult when I go backpacking, but the one piece casts better. (Darryl Hayashida) One of my favorite small stream rods is the Cattanach 6042 6' 4 wt. This rod is definitely a "parabolic" with an action that goes all the way down into the grip. For short 20-25' casts, it works like a fast "tip action" rod. For longer casts, you slow down the stroke and use the butt section for more power. It always takes me a few casts to "relearn" the rod, but after that it's a blast to fish with. This is a different approach than the one you took with the swelled butt. Now you have me thinking. How about sharing the taper? (Tom Bowden) I always enjoyed fishing a little bit slower short rod when I fished small mountain streams in North Carolina. Usually, they were relatively wind-protected and the slower rods tended to roll cast well (about 70% of casts) and made it easy to cast just the leader. (Jerry Madigan) I believe this is a very important point. The longer the rod, the more you built it fast. That means with a steeper slope. I "rebuilt" a 6’ two wt, that works very well for me, but looks like it should be very slow. But on my first two tries it was way to stiff. (Terry Kirkpatrick)
Is there any problem with using a 2 piece taper to make a 1 piece rod without changing any of the dimensions? (Joe Esther) I built six one piece rods (from a single 20' culm) a while back, from a range of 2 (and even 3) piece tapers, without playing around with the dimensions. They all came out well. There's a snapshot of them together on the gallery of my web page (see below). In general the lightness from removing the ferrule sped them up a touch and made them lighter in the hand, but I'd say you could be pretty confident building up most 2 piecers as a 1. By the way, the pick of the tapers were:
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