I have built several fly rods over the past few years and used L.A. Garcia's book as a guide. He says that the spine of a blank is where the "jump" occurs when rolling the blank. I have always tried to use this by locating exactly where the blank balances on the "jump" point. Recently, however, I have read some pieces that tell me the spine is where the blank naturally rights itself when bent. These usually end up as different places on the blank. Which sould I use?

The effective spine is the place where the blank, when pressured, locates itself and wants to stay put. It is then marked as the outside of the relaxed curve.

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Tom,

So what you are telling me is that when rolling the blank the spine should be marked after the jump, not on the jump. Is that right? I have a few rods that I built using the balance point of the jump as the spine. Now that I think about it, when I cast the rod is most comfortable when I hold it at an angle, and I am also really comfortable casting side arm!

So, to locate the spine properly, I should bend the blank, roll it, and find the spot that it doesn't want to roll out of. I should then mark the blank on the outside of the curve. Where do I put the guides now? I am finding my whole rod building life to be a lie!

Hmmm......maybe this is a perfect opportunity to convince my wife that I need a whole bunch of new rods!

Any more advice would be greatly apprectiated.

BOB

"So, to locate the spine properly, I should bend the blank, roll it, and find the spot that it doesn't want to roll out of. I should then mark the blank on the outside of the curve. "

Exactly. Now as far as where to locate the guides, what performance characteristics are you most interested in? There is not such thing as a wrong spine location, at least if stability is what you are after. All fly rods are 100% stable by the fact that the guides are on the bottom of the rod.

Some people feel an excellent overall position is to locate the guides ON the spine. Others who wish the greatest amount of power for fish fighting will locate the stiffest axis (that's where the blank jumps and is rarely on or opposite the spine) and locate the guides so that the fish pull against this axis. This is usually along the blank's natural concave bend.

I'd suggest taping the guides on and test casting in both positions and determining which works best for you. But I'd almost bet you will prefer the guides located on the effective spine.
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Tom,

Thanks for clearing things up. I rolled the tips of some of my fly rods last night and found that some are actually spined properly! I guess I got lucky a couple of times!

Bob Johnson

I too have been using the "balance point" where the rod jumps as the spine. I think so anyway. I roll the blank by hand, find the "jump", then balance it on the hardest point of the "jump". As I now understand it , this is the stiffest axis?
I just used three methods of finding the spine on a new blank 1)rolling - found nothing 2)horizontal spine finder - according to the above I located the "stiffest axis" 3)placing blank upright and pressing directly on the tip - "stiffest axis" previously marked was on the inside of the curve every time.
what's what? I know that this has been gone over and over, but the more information I get the more confused I get.
Thanks in advance, and thanks for a great site. I have learned more by reading the posts on this board for the last six weeks than in the two books on rodbuilding I have read (both informative and highly recommended on this site).

Tom

Right, the spine will be the place where it doesn't jump - the place where it wants to roll to, and stay put. When it is in this position, the outside of the curve is the spine.

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