Funny, years ago, arrow builders and archers would talk of their arrow's spline (which related to the stiffness of the shaft over its entire length and not a specific axis of effect) but today is also more commonly refered to as spine. Back to the subject at hand, my dad and I always placed our guides on our fly rods on the spine because he just knew it made for a more accurate rod, WINK WINK

Gene Bullard discussed it, and mostly put it off, in his books on rod building written and published in the late 1960's. He used the word "spine." I'd have to look in Dale's first book (1974) and see what exact term he used, it might well have been "spline." I can't remember.

I have known bamboo builders who referred to their individual rod strips as "splines." That could also have something to do with that term being out and about.

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Tom,

I can’t help but ask since you’ve taken an equally strong stance that consideration of the spine is much ado about nothing over on the BFHP thread in the subject as well. In your Rod-Building Book you discuss in detail, experiments that demonstrate the effects of the spine on casting distance and accuracy, even between the axis which are 180 apart. You also state that there’s no reason to build a rod without consideration of the spine, and I agree with that by the way. In addition, Rich’s recent article in Rodmaker took a similar stance on the significance of spine relative to rod performance. I’m just curious I guess, but what is it that caused you to change your position on this subject?

I guess I’ll be the lone dissenter here but why wouldn’t you spine the rod if for no other reason to understand it better? Personally, I’m interested to see if a rod has a significant spine or not. If not, don’t worry about it, but I’ve measured some significant differences in power between the relaxed spine and the stiffest axis on some blanks with a pronounced spine. And a lot of these spine effects seem to be strong in certain popular blanks coming out of China these days. The spines don’t always wander either since it depends on the particular manufacturing anomaly. I’ve seen a number of them go straight up the blank, seemingly related to variation in wall thickness caused by an off center tool. You don’t need a fancy spine finder to get a quick feel for the spine. Just flex the rod on a soft floor and start rotating it. You’ll feel the relaxed spine(s) and as well as the stiffest axis if there is one. It probably takes less than a minute to evaluate a blank.

I could make all the same arguments that you guys are making against the spine about things like optimizing guide placement, split grips, no foregrip, spiral wrap….a lot of guys on the street will tell you it’s much ado about nothing, and that there’s absolutely nothing wrong with their factory Croix’s and Loomis’. But that’s like dipping sheep, they all get the same treatment. I would suggest a couple of other things regarding the spiral wrap as the end all to the question of spine. First, not everyone builds guides under on casting rods, but when you do, you’re only optimized to reduce torsion under a fighting load. The other dimension that many don’t consider is that places the guides in the least favorable position for the forward cast. Given that it only takes a handful of ounces to roll the tip on many castings rods, I sometimes wonder how many times you’re torquing (fatiguing) the tip with a strong forward stroke casting with guides under configuration.

markG

Mark,
If there was a significant difference in the amount of force it took to deflect most blanks on the S1-S2 plane versus the N1-N2 plane then I might tend to agree with you that it is something that has to be dealt with but on modern blanks the difference is small. If the difference is large on a blank then that is a blank that I do not want to build a rod with because the spine is, in my judgment, a manufacturing defect. A perfect blank would have no spine. In fact, the graphite golf club manufacturers have done a lot of work and have been pretty successful in eliminating the spine.
If you are skeptical about the spine rotating, maybe rotating is too strong a word, shifting is maybe better, when more and more force is applied to the blank and it is deflected more and more try this. Take a scrap piece of blank and mark the spine very carefully. Now cut it into two pieces and carefully spine the two pieces. You will find on most blanks that it has moved. On most blanks you can detect the shift by just first deflecting the blank from the tip to the butt and then deflecting it from some mid point to the butt.
When you think about the manufacturing anomalies that cause the spine, particularly how the prepreg is wrapped around the mandrel, logically it has to move as you apply different amounts of force.
Plus I think that you can make an argument for aligning the spine anywhere. How about at 90 degrees to the guides so that it is approximately on the plane of the cast?
If you really believe that the spine is that important then, in my judgment, it should be found dynamically like the rod will be used, rather than statically, dynamically by measuring how the resonant frequency changes as the blank is rotated. If you try this experiment, rotating the blank in a few degree increments and measuring the resonant frequency on each of the increments and then comparing the spine that you find this way to the spine that you find statically, or just by bending the blank, I think that you will be surprised to find that it is in a different plane.
You make a good point about the torque that is created when you cast but isn't the torque created by the cast going to be the same if the guides are on top or bottom if the plane of the cast is 90 degrees to the guides.
I would agree with you about the effect on performance of split grips and no fore cork but not on optimizing guide number and positioning. Optimizing the number, size and position of guides is, in my judgment, the most important thing that a custom rod builder does in terms of rod performance.
By the way, how are you doing with the measurements on the titanium pieces that I sent you?



Edited 1 time(s). Last edit at 01/27/2006 11:50AM by Emory Harry.

Hi Mark you are not the only decenting person. In the old days It was more important because the rods could de-laminate and you would have failures. Today this isnt such an issue. You are right, there is influence on how the rod casts and power to a small degree. I was reacting more to the poster who seemed in fear that he was ruining the rod if he didnt do it. I still spine the rod, but more out of a professional attitude and habit rather than necessity.

As to the spiral wrap issue, though I am not a proponent of the technique I have done some experimentation. I have discovered that though your casting distance is reduced, you can still cast an effective fishing distance. This was a test with three of the same blanks put together three different ways and cast 100 times each with the same weight plug, Same line and Same reel. The Spiral wrap got the shortest distance by an average of 15 feet but like I said I could still cast far enough to fish effectively for largemouth and similar species. With lighter weights it might be more pronounced but at this time I can say.

Bottom line is you can spine a rod or not and still have a fine piece of equipment. Not something to lose sleep over.

Doc,
I am surprised to see you wade into this discussion. You are usually such a nice, easy going guy and seem to try to avoid any controversy.
I am especially surprised to see your comments on spiral wraps. I am on your side about the spiral wrap but there are a lot of builders that feel strongly about its advantages and are probably going to give you a bunch of heat. I have quit commenting on spiral wraps because every time I do I get so much heat and the discussions quickly seem to me to get irrational. Now when it comes up I am just going to tell everyone to go argue with Doc Ski.

You trying to get me in trouble Emory? LOL You are right I try to avoid such subjects but I was only remarking on my findings on casting. I know there is a large following for this technique and it obviously works for those who are so ardent about it. As with all things there is more than one way to do things, same with putting guides on a rod. My original criticism of casting and spiral wraps was the loss of distance due to the change of direction of the line. Well there is a loss(from my tests) but not sufficient to warrant not doing spiral wraps. The torque thing has merrit if you dont gimbalize your rod, If you do gimbalize it isnt that big of a deal. Landing a fish faster with a spiral? Dont take me there. Bottom line: If doing spiral wraps work for the builder then dont change also the same can apply to the conventional way of doing things. New ways arent always the best and the old ways are not always the worst. There are some venues where spirals will meet with a lot of resistance but it wont be because of me, I can build one if asked to do it. As to the heat, will I have gotten it in more than one area before. Glad to see you back in the battle. I can only guess that means you are getting some spring back in your step. Doing a sturgeon trip on the Columbia in June, will I be passing by you at all?

Doc,

That's somewhat my point. You could simply build a casting rod on the curve, guides up, full grip and seat, foregrip etc. and you'd have a fine piece of equipment. Look at how many rods Gary Loomis built that way, and I doubt he's loosing any sleep over it! I wonder how much difference in casting performance you could measure between a std. Fuji spacing vs. Tom's refinement (which I think is a good system BTW). And if it wasn't a large difference, then would that make further refinements irrelevant? I don't think so. Maybe one builder wants to focus on a light tip, another on minimum angles and another optimizing delivery of the load deep into the blank. I tend to like Rich Forhan’s way of thinking about a custom rod, which is to refine, and to put as many little pieces together, especially if they're easy. As far as spine goes, there are a significant number of top notch good builders who have claimed that they can feel and measure differences between the two relaxed spines (0 and 180) and if that's so, then it'd be hard to imagine that a strong jumping spine off axis to that is insignificant.

Emory,

I wasn't disputing the idea of a wandering spine, just adding that I've also seen a number of straight ones. If for example, if a mandrel was slightly off center, you'd have a spine that went straight up the blank. Don Phillips has a good discussion of a number of the root causes of spine in his Technology of Fly Rods book. I've seen some fairly pronounced spines in some of the newer blanks resulting in a difference in power in the range of 5-10%...in that range it's something you can feel in your hand. The interesting thing here is that spines can be like snowflakes and it's also a matter of degree. If a blank doesn't have a spine, or it's soft, then you've got little to consider. If a blank has a noticeable or very pronounced spine, then I tend to consider the specific application. If I'm building guides under and I simply want every ounce of fighting or lifting power, I might put it on the stiffest axis, or jumping spine. On the other hand if it's guides up, I might not want the least stable guide position on top of the least stable blank orientation. Certainly the guides will dominate the spine, but I'm not sure that makes the spine insignificant, esp. if it's fairly pronounced.

As far as the spiral wrap and twisting goes, I think there are a number of good applications for them. But when you hear people say that guides under will completely eliminate torque etc, I think it gets you thinking in only one dimension. It's certainly true that guides under is the most satble configuration when the load is directly under the tip. But consider a sideways load (hook set, dragging a fish etc) and they torque as much as guides up. As far as casting goes, everything is reversed and the guides up are in a more stable position for the forward cast.. Now it could well be that any loss of power and distance for casting with guides under is acceptable, but still it's not optimum. And many spiral advocates worry about twisting and fatiguing the blank as well. It could be argued that if the tip is down you're more likely to roll it over on a hard forward cast, and if you're like me you've got a heck of a lot more forward casts than you do fights. That's why when I want max casting performance out of something cranking rod, which I also tend to fish tip down, I still put the guides up.

mark

Doc & Mark,
Well, son of a gun, this discussion must be over because there isn't anything you said that I would disagree with.

Mark, You did not answer how you are coming with the testing of the titanium?

Tom, thanks for the info, I build mostly casting rods and and therefore the guides are on top so I always orient the spine just for good measure.

I build walleye trolling rods predominantly and I guess that's why I'm such an advocate of the spiral. It makes perfect sense in a no-cast world. We don't cast (the rare times we do, we use light, light jigs and spinning set-ups 90+% of the time) so it's not relevant for my application.

Putter
Williston, ND

Emory,

I've got the test station set-up and made a couple of quick measurements to get things working. I want to put that Ti handle on a blank and compare the vibrations at a few different points. I should be able to send you some pictures next week.

mark

Mark,

I did not change my stance at all. I gave the reasons that many builders orient the spine the way they do, then went on to mention building on the straightest axis, which I have always preferred. You might want to read it again. If anything, that entire chapter was put in there to show that spine orientation does not have any effect on rod stability, which is the foundation behind nearly every other written document on the subject. They're all wrong - you cannot creat a stable rod by any particular orientation of the spine.

It has always bothered me to see new builders getting so carried away, confused and even downright worried that if they don't somehow get this spine thing "correct," that something terrible is going to happen to their new custom rod. That was the reason I put the chapter in the book, and it has even caused more than one new builder to write me saying, "But you didn't tell me where to put the spine!" I purposely didn't tell readers where to put it, because there is no right nor wrong position.

As far as casting - you're not possibly going to flex the blank as deeply or under as much load as when you're fighting a good fish. I tend to think rod twist on the cast is pretty irrelevant.
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Edited 1 time(s). Last edit at 01/27/2006 04:48PM by Tom Kirkman.

Tom,

Thanks for the reply and I did read the Chapter very carefully. Actually what you wrote was one of the better, most clear discussions on spine that I've seen to date. The part about spine and the dominance of guide placement is obvious and well said. I’m not trying to be a jerk here, but I think spine is somewhat technically interesting…sick I know! What I'm referring to here is on page 18, paragraphs 2-4. You discuss where to place the guides relative to the spine as well as the significant effect of placement on performance 0 vs. 180 to the spine. Statements like there's "no reason to fail to build the rod without regarding the spine", or "spine does make a difference, often a huge difference in terns of the castability" lead me to believe it's anything but of no consequence. Your discussion on the significant effect of the hard side on power was well said too. Athough Rich's article was a little less straightforward; the conclusions are in the same vein. 'finding and using rod spine effectively is just another feature" (of optimizing custom rods). guide placement relative to the OSCAR to enhance performance...etc.

I certainly agree that folks shouldn't loose sleep if they ignore the spine, and it's not like the blank is going to come apart on you if the tip twists around either, fighting load or casting. What I would promote though, is by having a good fundamental understanding of spine, you can use it if you want to, or at least be able to discuss it, pros, cons, with someone you might built a rod for.

I wholeheartedly agree that builders should understand what the spine is, what causes it, etc., etc., That way, they won't have to worry over whether they're orienting it in the "correct" position.

Most of the confusion stems from builders who really don't understand it and therefore are more concerned than they need to be with it.


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