How do you find the strongest axis on the lower half of a 4 piece fly rod blank?

Tight lines and frisky fish

RJF

[www.rodbuilding.org]

Generally it'll be along the straightest plane, curve up.

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Robert,
If you wish to spine a blank - the most important sections to spine are the tip (S4) and the next section down (S3).
When I spine the butt (S1) - I assemble S1 and S2 and spine them assembled. If S1 has a logo - make sure that it is oriented properly when spined. If not - rotate S2 until the logo is oriented properly.
Herb

Robert,
BTW - again, IF you do want to spine a 4 pc fly rod - after you spine the S4, S3 and the assembled S1 and S2 - you must assemble all sections and spine again - butt on a hard surface (Floor).
Since all sections will affect the spine of the assembled rod, you may have to re-mark S3 and S4 if they twist while spiniing. Keeping the rod all assembled - simply erase the spine marks on S3 and S4 and remark S3 and S4 while spining the assembled blank.
Herb

As long as the same force is applied a rod will cast to the same place - unless the tip top is loose. No amount of fiddling with spines of rod segments will make an angler a more accurate caster.

If it's difficult to find it doesn't matter. No significant difference no matter how you orient it.

The spine on a 4pc fly rod butt section is irrelevant! Does not effect anything and has no benefit!



Edited 1 time(s). Last edit at 04/12/2021 10:23PM by Phil Erickson.

I watched a video by Gary Loomis. In it, he stated that the guides should be placed on the spine, or on the belly of the rod blank. His reasoning was that when the rod is loaded, and unloaded, there is a natural oscillation that takes place at the tip. If the guides aren't aligned properly, then the caster will cast, usually, with the guides facing skyward, or toward the ground. The rod will begin to oscillate sideways, and throw off the accuracy. Of course if we are using another plane for the cast, then this no longer applies. The strength differences are also negligible. The guide placement with relation to the axis won't make much difference, though building along the stiffest axis will give you about 2% more lifting power.

So for me, I will stick with placing my tip to midpoint guides on the belly, and my midpoint to stripper on the stiffest axis.

Tight lines and frisky fish

RJF

The spine won't be on the "belly" of the rod blank. The belly is the underside of the natural curve or warp of the rod's straightest axis.

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Claims that building on (or off) spine makes a rod more accurate or stronger or cast farther add credibility to accusations that fishermen are compulsive storytellers: full of bologna.