Tom....
I'd have agreed on that in the past. The slight softening in the other direction is to be considered, also. I used to think, too, that this might help tracking.
Theoretically, if the spline is oriented on the side of the caster's thumb OR directly on the opposite side....not off an some other angle, it ought to help tracking, whereas if it is say 90 degrees off the casting rod plane, it then should provide a tendency for the rod to twist on either the pickup or the forward cast. I'd think THAT would lead to bad tracking of the rod tip. This is what Don Phillips called an, "eccentric spine". (p 67 of his book.) The articles I've read on the subject show no real agreement, however.
Don feels that any "selective stiffening" (like with a significant spline anywhere on the blank) yields a blank which is basically unstable. In that case, he says, "...Unless the fly rod is restrained from twisting throughout its length, the rod will tend to flop over to its orientation of least resistance:..........." He goes on to say that with casting, this, ".....involves repetitive, reversing flexure, the rod tip oscillates from side to side during the forward and rearward casting strokes as the tip twists and untwists. This oscillation hurts both casting distance and accuracy, since the fly line unfailingly follows the rod tip motion."
I suppose, this is the reason that modern rod makers have taken pains to minimize or eleminate ANY residual spline rather than taking the path of controlling its location as they did in the past when the technology hadn't developed to the point of virtually eliminating it.
Don goes in to the many reasons for spline including blank void inclusions, pattern edge ridge, and overall rod warp due to curing with residual internal stresses, fiber-resin de-bonding, and asymmetrical masses of resin. Each represents manufacturing imperfection. He gives the distinct impression that any significant spline at all is the result of poor blank manufacture.
For a lot more detail, including the theory of secondary splines, read his entire Chapter 7.
Randy Swisher could probably give us the latest info from Sage on this subject. I'll ask him.
Gordy
From: "Tom White" <tomw1483@xxxxxxxxxxxxx>
To: "'Gordon Hill'" <hillshead@xxxxxxx>
Subject: RE: SPLINES (SPINES)
Date: Sat, 3 Sep 2005 14:13:50 -0400
Gordie;
I have a question on # 3-a&b.
If the ?BOW? is up on a blank, and you place the guides on the bottom;
You would have more ?Power? on the pick up cast, and softer on the forward cast.
Also better tracking on the forward cast.
This is the way I see it. I might have mis-read this mail?
Tom
Capt. Tom White
PO Box 500085
Marathon, Fl. 33050305-743-0055
Cell: 305-304-8540
tomwhite@xxxxxxxxxxxx www.tomwhite.com
FFF Certified Casting Instructors Workshop (CCI)November 2005-----Original Message-----
From: Gordon Hill [mailto:hillshead@xxxxxxx]
Sent: Saturday, September 03, 2005 1:59 PM
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Subject: Re: SPLINES (SPINES)
Walter....
This is by far the best set of answers I got !
As far as I know, the only rods which were made without any spline, were the tubular metal rods, including the beryllium copper step-tapered fly rods of 1940.
I consulted Jeffrey L. Haton's new book, "ROD CRAFTING, A FULL COLOR PICTORIAL AND WRITTEN HISTORY FROM 1843 - 1960", since he had many examples of greenheart and other composite wood fly rods.....but found no mention of splines.
Gordy
From: Walter Simbirski <simbirsw@xxxxxxx>
To: Gordon Hill <hillshead@xxxxxxx>
Subject: Re: SPLINES (SPINES)
Date: Fri, 02 Sep 2005 20:48:06 -0600
----- Original Message -----
From: Gordon Hill
To: flysoup@xxxxxxxxxx ; sobbobfish@xxxxxxx ; rtab@xxxxxxx ; CAPTPERMIT@xxxxxxx ; creangler@xxxxxxxxxxxxxx ; dwright@xxxxxxxxxxxx ; daver@xxxxxxxxxx ; dennisg@xxxxxxxxxxxx ; captdoug@xxxxxxxxxxxxxxxxxxxxxx ; dsprague01@xxxxxxxxxxx ; ephemera@xxxxxxx ; brushycreekfc@xxxxxxxxx ; keysjake@xxxxxxx ; barefootj@xxxxxxx ; bradyir@xxxxxxxxxxxxx ; flyfishar@xxxxxxxxxxx ; ken.cole@xxxxxxxxxxxxx ; captkirk@xxxxxxxxxxxxxxxxxx ; glbaggett@xxxxxxxxx ; mkreider1@xxxxxxx ; martyt@xxxxxxxxxx ; niallogan@xxxxxxxxxx ; pminnick@xxxxxxxxxxxxx ; bigfly@xxxxxxxxx ; whorwood@xxxxxxxxx ; flycasts@xxxxxxxxxxxxx ; sheila@xxxxxxxxxx ; scjacobs@xxxxxxxxxxxx ; tharper@xxxxxxxxxxx ; tomwhite@xxxxxxxxxxxx
Cc: mildbill@xxxxxxxxxxxx ; caddis@xxxxxxx ; Brydnlnims@xxxxxxxxxxx ; cezannealexander@xxxxxxxxxxx ; crazycharlie@xxxxxxx ; croberts@xxxxxxxxxxxxxxx ; blacksalmon@xxxxxxxxxxx ; DermSox@xxxxxxx ; gladesflybum@xxxxxxxxxxxx ; hillshead@xxxxxxx ; iverson@xxxxxxxxx ; jfs523@xxxxxxxxxxx ; jerry_puckett2001@xxxxxxxxx ; kathleen@xxxxxxxxxxxxxxxx ; thedamselfly@xxxxxxxxxxx ; plami@xxxxxxxxxxx ; ray@xxxxxxxxxxxxxxxxxxx ; kerrrc@xxxxxxxxx ; simbirsw@xxxxxxx ; bobbeanblossom@xxxxxxx ; hillcathy@xxxxxxx ; donjack@xxxxxxxxxxx ; douglas.swift@xxxxxxxxxxxx ; erniemaynard@xxxxxxxxxxx ; flyfsfrank@xxxxxxx ; gregrahe@xxxxxxxxxxx ; ianmuirhead@xxxxxxx ; jeff@xxxxxxxxxxxxxxxx ; t.maltese@xxxxxxxxx ; skifishvail@xxxxxxxx ; jfv@xxxxxxxxxxxx ; trallag@xxxxxxx ; mollysemenik@xxxxxxxxxxxxxxxxxxxxxxxx ; paul@xxxxxxxxxxxxxxx ; fraudflies@xxxxxxx ; shane@xxxxxxxxx ; snowmonkey29@xxxxxxx
Sent: Friday, September 02, 2005 3:32 PM
Subject: SPLINES (SPINES)
Hi, Group....
Let's discuss the fly-rod SPLINE. (Some, such as Don Phillips, prefer to call it the SPINE.)
1.) What is it ?Due to manufacturing issues graphite blanks do not come with perfectly uniform walls. Grpahite comes in long
thin strands which are packed around a scrim wrapped arbor. The whole is then wrapped with cellophane and
then hardened chemically and with heat to create a rod blank. During the process the arbor/scrim combination
will not be perfectly centered in the graphite blank. The result is that one side if the rod will be a bit stiffer than
the other sides. This can be felt by bending the rod and then rolling it while it is bent.
2.) On which side of the blank do most rod manufactures place it as they make up a rod ?
Most rod manufacturers actually look for the orientation in which the rod is straightest when sighted down
the length of the rod. This makes it easier to align the guides when wrapping the rod. This is generally
assumed to be the stiffest side of the rod but may not coincide with the spine as identifed in the
previous answer.
Another test for rod spine is to stand the blank section up perpendicular with one end resting on the floor.
If you press straight down on the other end of the blank section it will consistently bend in one direction.
This will tend to agree with the spine identified by straightness.
Guides are usually lined up with the stiff side of the blank or opposite the stiff side. (Some rod builders will
align the guides at 90 degrees to the stiff side of the blank but usually it is on or opposite the stiff side).
Lining up the guides on the stiff side gives the fastest rod action but the rod may twist in some cases and a
ffect casting accuracy or the action of the rod when playing a fish. Putting the guides on the opposite side
will make the rod a bit slower but it tends to cast more accurately and doesn't roll or twist when playing a fish.
With the tendency towards faster rods most rod manufacturers place the guides on the stiffest side of the
blank as identified by blank straightness or the test described two paragraphs earlier (i.e. not the test
described in question 1)
3.) What is its effect ?
a. In picking up line for a back cast?
Following the guides on the stiff side scenario this would make the rod slightly slower on the back
cast. This would make the pick up less noisy on the water.
b. In making a forward cast. ?
Maximum stiffness in the direction of the forward cast would maximize energy transfer and distance. A lot
of people like to turn the rod 90 degrees when casting to avoid line slap and/or for biomechanical reasons
so the spine will not be providing them any benefit.
4.) Does placement of the spline (spine) have any effect on tracking ?
Not of the rod hand but it can improve tracking of the rod tip.The amount of the effect depends on the difference
between the spine and the rest of the rod.
5.) You have two graphite fly rods. Both are top-of-the-line rods made by a well reputed rod company. One was purchased 15 years ago.....you bought the other yesterday.
Question: Is there likely to be any difference in the splines (spines) between these two rods ?
Yep - improvements in manufacturing methods has reduced the erratics in the wall thickeness. This makes the spine
less noticeable. Some manufacturers claim a Uniform Wall Thickness but from what I've seen a perfectly uniform wall
every time is still not guaranteed.
6.) Do most bamboo rods have a defined spline ?
Yes. Bamboo rods are typically made up of 6 triangular pieces resulting in a hexagonal cross section. While the rod builders
do everything they can to have uniform stiffness in each of the 6 pieces there will be discrepancies introduced by growth
rings etc.
7.) How do you find it ?
I know of 4 methods. 3 I've already described. The 4th one I know of is to suspend the blank horizontally at the butt end.
A small weight is attached to the tip end and then the blank is rotated. The spine is identified when minimal deflection is
found in the blank.
Two good references for this information, are Dale Clemens book on rod building, and Don Phillips, "The Technology of fly Rods".
Gordy
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