Tom
I just recently purchased your book Rod Building Guide. I guess I am one of the guys you were refering to when you said confusion still exists even among those builders who have built many rods. I learned to build rods by reading Dale Clemens books 20 years ago. In Advanced Custom Rodbuilding Dale states that the point where the rod seems to jump or produce increased resistence is the spline. In Fiberglass Rod Making it is stated that the spline or high side is the position is where the blank has slightly more power. In your book you state that the spine is that plane or axis where the blank exhibits its least resistance to bending. So now you can see where the confusion is. Dale is saying the spine is at the strongest point on the blank and you are saying it is at the weakest point on the blank. I checked a few blanks that I had in my shop and when I found the spine the way you said and put it on top or the bottom the rod always bent to the left or right . Is this normal. Did something change in blank making from 20 or 25 years ago in regaurds to spines? I will probably confuse more people with this post, but if you can share any more thoughts on this that might help please do.
THANKS TIM

Nothing changed in the blanks, but if you read both of Dale's books and his issues of the RodCrafter's Journal you will see that he changed his mind along the way and ended up calling the spine the outside of the relaxed curve, which is the position that is now regarded by most rod builders as what we call the spine.

Keep in mind that the spine is not a thing, it is an effect, so we are just using a term for a reference point to remind us where that effect lies. In the last issue of RodMaker I delved into this a bit deeper in the Q&A column.

If you read all the various rod building books you see all sorts of references to the spine and where it is. But what we are concerned with is that point where the blank wants to naturally locate itself when pressured. You can call the spine the axis 90 degrees to that, or 50 degrees to that, or on it or opposite it, as long as you remember where that point lies in relation to your own reference. Again, most of us have settled on a point of reference which is the outside of the curve formed when the blank is pressured and allowed to roll to this softest axis. This allows us to discuss it as we are all on the same page.

One thing you do want to keep in mind, and this is a point that is not understood by many of the various book authors, is that the softest and stiffest axis's on a rod blank are not necessarily 180 degrees opposite each other. Once in a while they may be, but most often they are not. The old adage about putting the spine on top for better casting control and on the bottom for better fish fighting control doesn't hold water in most cases.

The stiffest axis is usually found along the blank's natural concave bend and will be located anywhere from about 45 to 170 degrees to the softest axis (spine). That is why you notice the blank crooking to the left or right when you put the spine on top or bottom. Most manufacturers build on the concave bend which gives the straightest axis in an upright position. They normally disregard the spine.

As far as where you align your blank's spine is up to you. There is not any wrong position, depending of course on what particular performance characteristics you prefer in your rod. Remember that rod stability is governed by guide placement, not the spine. So rod twist while the blank is under a fish fighting load cannot be handled by locating the spine in any particular way. Many rod builders align the spine in the casting plane and use what they feel may be a bit better tracking during the casting motion.

Look at the spine info on the FAQs page for more ideas. Also the thread on rod spine just below this one has some ideas you may be able to use.

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While I have a moment I'll copy this over and save you the time from hunting it down.

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5. Where should I locate the spine on my rod blank in relation to the guides?

There is no wrong position to locate your blank's spine. Where you do put the guides in relation to the spine, however, will result in certain performance characteristics being either enhanced or reduced.
There are three viable options as to where to locate the spine.

1. Spine on top - This option gives a bit more power on the forward cast but a bit less for line lifting (fly) and fish fighting.

2. Spine on bottom - This position puts the spine into strong play (better tracking) on the forward cast and gives you slightly more power for lifting line off the water (fly). Opponents of this method say this position will lead to rod twist when fighting a fish. This is not true, however, as guide position alone determines rod stability. (More on this topic can be found in the next question.)

3. Disregard spine and locate the rod's stiffest axis so that the fish is pulling against it (A blank's softest and stiffest axis are not necessarily 180 degrees opposite each other). This usually locates the blank's natural bend in such a way that the butt and tip are "up" and the belly of the blank is "down". This puts the maximum amount of power into play for fish fighting but may result in slightly less casting accuracy/tracking.

6. How do I make a rod stable under load?

The only way to create a stable rod under load is to locate the guides on the bottom of the rod. Under load, the line will seek the lowest point, regardless of where you locate the spine. The greater the load, the greater this effect will be. By their very nature, all fly and spinning rods are inherently stable. Casting rods with guides located on top, are inherently unstable and will try to twist when put under load. A spiral wrap, which transitions the line from on top to the bottom of the rod, will create a perfectly stable casting rod.

Tom,

Now I'm really confused. I think I now understand the concept of the relaxed curve being the plane commonly referred to as the spine and that when one applies flex to the blank it will naturally fall so the relaxed curve is the outside curve.

What baffles me is if one wanted to align ones guides along the stiffest plane how would one find that?

-Steve

It will usually be found along the natural concave bend of the blank. Just sight down the blank until the tip points "up". You can also roll the blank just as you would if looking for the spine, but feel for the stiffest axis. This is a bit tricky but you'll know it when you hit it - the blank doesn't want to stay put. It will try to roll away from that point very strongly and when you are right on top of it the blank will roll away equally to one side or the other rather than consistently to one particular side. That is the point some refer to where it "jumps" or "kicks". That's your stiffest axis.

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Aha ... so that's what it is ... :) I have been trying two methods of spine finding with varying results.

One I place the blank vertical with the tip on the floor (protected of course) and press down on the butt. This seems to always give consistant results and places the relaxed curve outwards.

The other I use the classic method; butt on the floor, blank at 45 degrees and roll the blank. I suppose the popping I feel must be the blank jumping off the stiffer axis?

-Steve

Tom
Thanks for your reply. My problem wasn't with finding the spine or where to put it , I just couldn't figure out why or how the position of the spine changed from 20 years ago. I build most of my rods with the guides on the stiffer axis. most of the rods I build are for use on the river for bass and walleye around the discharges of power plants. I want the blank to be in the best fish fighting position because of the faster water from the power plants. So I guess I have been doing it right. After reading your book I had some doubt. I think that I would have a tough time convincing a customer that his rod ,that has a bend in it to the left or right, that he just paid X $ for is going to be better casting then if it were straight. Thanks again for your help clearing this up for me.
Tim

What you say about the rod pointing off to the left or right is exactly why the manufacturers don't spine their rods. They build on the straightest axis even if it means that their rods may not perform as well.

On a custom rod, the custom rod builder is right there to explain to the customer why a straight rod isn't necessary and why proper spining is and why it will cast better if the spine is used to track in the plane of the cast even if the rod looks crooked.