Sorry if this is the topic that will never die, but I would like to hear some opinions on a small issue I have with a rod I'm building now. I've read quite a bit on the topic of splining and have always done it, but at just over a dozen fly rods under my belt (I build for myself), I'm still a novice.

One of the rods I'm currently building is a multi-piece travel rod from a respected blank manufacturer. When I received the blank, I noticed it had obviously been marked by hand for alignment of the sections. When I tested the flex, the markings were clearly opposite the spline, which makes sense on a fly rod. I played with guide placement, wrapped the rod and prepared to put the finish coat on the wraps. Sighting down the blank to make sure the guides were aligned, I noticed a distinct lateral curve in upper third of the blank when aligned this way. With it being a travel blank, I found that I could tweak the alignment of the sections to put the guides on a straight line in the casting plane.

So I guess my question is whether to move the guides in the top 2 sections to place them on the straightest portion of the blank or just leave them as-is on the soft side of the spline? Am I likely to see a difference in performance either way? The blank test-cast fine in the backyard when I was tweaking guide placement, but conditions were very windy at the time. I'm inclined to put the final finish coat on and fish it, but thought I'd check opinions here first.

The spine is sort of a mythical thing, if any ark in the blank I want the whole rod to be straight and the arc to point up to the sky, so guides and such pull it back down. I also take the rod by the grip and waggle the tip up and down vertically and see if the tip cycles and wants to travel in a straight plum line or wander off. I try to keep the rod straight. "Spine, Spine, everywhere a spine messin up the scenery and breakn' my mind, do this , don't do that, can't you read the spine?".



Edited 1 time(s). Last edit at 03/12/2007 09:37AM by Chris Karp.

The spine doesn't have a "hard" and a "soft" side. Only soft. The stiffest axis is not 180 degrees opposite the spine, it's along the straightest axis.

Having said that, I'd do what Chris mentioned. The spine has no effect on rod performance.

...............

Curvature of a blank can have several reasons. The first being the mandrel or the tooling was bent out of shape before or during the curing process. The second possibility is a term we used to use when I was manufacturing advanced composite parts called eccentricity. This is when the outside diameter has shifted relative to the tool center line. Even though the fiber content remains relatively around the mandrel, the shifted circular area will alter the shapes moment of inertia characteristics. This fiber misalignment will cause the part to warp or curve to the weakest side. The third possibility is if the blank cures with significant internal residual stresses, warping will result, which can not be straightened unless the resin is of the thermoplastic type. Putting guides on the opposite side of the warp does not solve the problem with the rod blank. If you are buying first line blanks and get a blank that's curved or bent send it back that's covered under manufactures warranty. If it's a discounted blank or second I guess you 're stuck with it.

Thanks guys,

Maybe I used the wrong choice of words in describing soft as opposite the spline/spine. In my limited experience, every blank I've built on had what I refer to as a soft side. Not sure if we mean exactly the same thing by "soft" but when I put pressure on the blank (or upper section(s) it will come to rest with an arc in the same axis everytime. I have no idea where the spline/spine is in relation to the "soft" side or if a spine even exists, but intuitively I've been putting the guides on the inside of that consistent arc, or softest axis. Sorry if I'm explaining the obvious, but I just want to be sure we are referring to the same thing.

With an absolute statement like: "The spine has no effect on rod performance", I just want to make sure I truly understand. If we thow away the word spline or spine and talk about the blank only in terms of the soft side vs. the straightest axis, which one would you choose? Intuitively I'd place the guides on the soft side of the blank as I usually do, but choosing the straightest axis also intuitively makes sense. This is the first time I've built on a blank that was not quite straight and the choice between the soft side or the straight axis or are at complete odds with one another; they are about 90 degrees apart. So in terms of casting performance from what should be a high-performance fly rod blank, any advantage or disadvantage in choosing the soft side or the straightest axis or does any axis really matter?

Thanks again. I really appreciate the feedback....

IMO - you can throw out the terms spline and/or spine.

if the rod it really not straight, meaning its got a nasty crook in it - I'd be sending it back for a new one. if its just off a little. I'd find the straightest alignment possible and go with that. The location of the the "soft axis" being 90 to the "straight axis" is not going to make a difference.

If the spine has no effect to the rod,,, why then do some build the spiral wrap rod? And the confusion between spine and spline is tha in Clemen's book, spline was a typo!


<*)))><

Can't speak for anyone else, but I spiral my baitcasters because it does indeed make a difference. A very noticable difference. A rock steady difference. I've also spent a good bit of time fretting over the spine/spline on fly, spinning and casting rods in the past and IME, the time could have been much better spent. No matter how much time I spent on finding the spine or locating the guides relative to the spine, it just didn't make much difference in rod performance. About the only benefit was knowing I took it into consideration in the builds.

The rod , like most things , is abet to take the path of least resistance, now where you want your guides in relationship to that, is up to you.

Again I reference the spiral wrap,,, the placement of the guides is VERY relevant to the spine, other wise, the principle of the spiral wrap is irrelevant.

I have found blanks to have NO spine,, and blanks to bounce like a kangaroo.. this is true for bamboo blanks as well.


<*)))><

Spiral wraps are used to create a stable rod - putting the guides on the bottom of the rod creates an inherently stable rod. Having the guides on top of the rod means the rod will be inherently unstable. Spine has nothing to do with any of this and is not the reason for using a spiral wrap.

The effective spine is the outside of the curve when the blank has been pressured and allowed to roll to the position it desires. However, this in no way approximates what happens when a fish pulls on a line running through guides attached to the rod.

.................

The spiral wrap eliminates the torque effect of a line load (fish) on the guides, trying to pull normally upright guides (traditional casting rod) to the bottom. Not relevant to spine.

==dave==

Right, I was going to ask Art what in the **** did spine have to do with a spiral wrap?

I never bother with rod spine anymore. I find the straightest axis and build along that. It's the most powerful axis anyway although I know it's only a small amount of difference in power between that and the softext axis. But I build on the spine and with the spiral wrap I don't have to worry about rod twist.

I have seen another way a blank has obtain a less than straight character that Mr Taylor spoke of. He spoke about curviture, but I've seen the whole (straight) tip section skewed a noticable amount right off of the ferrule as if everything was straight but the connection and this caused an deviation from both sections being straight at some point in the 360 degree rotation of the blank

No wonder the mythical spine question just won't die.... somewhere in these posts, someone might have actually answered my question, but it probably got lost in the debate ;-) I've noticed this in past threads about spine. The novice that asks the question gets a lot of enthusiastic responses, many of which don't have much to do with the problem at hand. Don't get me wrong, I do appreciate the responses, but it can be pretty amusing at the turns these discussions take.

Actually, just putting my thoughts in writing helped me think through this to a point where I'm quite comfortable with my own conclusions. When I take the rod fishing in the next couple of weeks, I'll have forgotten all about the question (and debate).

Thanks again!

Are you guys telling me that the spine that is refereed to in just about every rod building publication that I have read , does not exist or have an effect on the position of the guides??

With wrapping a spiral, I place the "bottom" guides on the spine, because that is the path of least resistance on that rod.is The rod will naturally want to bend in that direction,,, hence,, you are eliminating the torque that would otherwise twist the rod if you were to have the guides on top, in the customary casting or trolling rod. Having you fight both the fish and the rod, to keep your reel on top of the rod .

And Shawn, I don't understand what **** means, could you elaborate please?

Art,

It exists, but has almost no bearing on rod performance. And it certainly has no effect on rod stability. Rod twist is caused by guide location, not spine location. If the guides are on top of the rod, the rod will try to twist no matter where you orient the spine. If the guides are on the bottom of the rod, the rod isn't going to try to turn over on you, and this is also regardless of where you orient the spine. Spine plays almost no role in rod stabilty.

One of the problems is that flexing the rod by hand and having one flexed by a fish pulling on a line strung through guides are two entirely different things. What happens when you flex a rod by hand and that which happens when fighting a fish are not at all the same.

Yes, most of what you've read on rod spine in most rod building publications is based on myth, not fact. There has never been any evidence nor data supporting the idea that spine orientation affects rod stability nor casting accuracy.

.........



Edited 1 time(s). Last edit at 03/12/2007 11:17AM by Tom Kirkman.

Where then is the TOP of the rod?????????

What dictates the top of the rod, and please don't tell me it is the "0" axis.

And now ALL the books published that include information regarding spine are myth, then the sponsors on the left that sell spine finders are selling something that is not needed because the idea of a spine and it's relationship to guide placement is now all myth? Is that what your saying ?

I agree with Tom, BUT, if using the spine makes someone feel better, than go for it!! It's sort of like, if one feels that using a red jig will catch them more fish, than do it.

Mike (Southgate, MI)
If I don't want to, I don't have to and nobody can make me (except my wife) cuz I'm RETIRED!!

I pretty much agree with the spine having little to do with nothing, but I have done it for so many years that I do continue to do it today.

If the rod blank is straight, I spine it and put the guides as it tells me to do it. The blank seems to WANT to bend along that plane and I don't want to fight with it's inherent property there (as long as it's straight to begin with).

But I don't think it's a REAL important matter, personally, after toying with it a few times. Old habits die hard and that little voice keeps saying, "But that's the way the blank WANTS to bend...".

Putter
Williston, ND

Yes, most of what has been written about rod spine is based on hand flexing the blank, which does not in any way approximate how the rod is used in an actual fishing situation. It is mostly myth and not anything based on study, data, etc.

If the guides are on top of the rod then the rod will have a tendency to twist when load it applied. If the guides are located on the bottom of the rod (spinning, fly, casting spiral wrap) then it won't have that tendency.

As far as what constitutes the "top" of the rod, well, let's say that on most casting rods used with baitcasting reels, the reel is on "top" of the rod. On a spinning rod the reel is on the "bottom" of the rod.

...............