I think I have read something about this matter but will still insist. If you´ve seen SAGE blanks, they are marked with white dots to indicate the "straightest visual line". I wonder now what that is, is it the spine?
I made the test to find the spine on three different models of these fine blanks. Usually I found the "weak side" opposite or almost opposite to the white dot´s line. Should I place the guides leaving the dots "up-side"?

Anyone has a better knoledge to share here?

Thanks!

Have a great "building week"!

The white dots indicate the straightest axis, which will put the blank's natural curve, if it has one, either straight up or straight down. This is the position that most customers will hold the blank/rod in when trying to determine if they are "getting a straight rod".

The effective spine is something else altogether. Please read the thoughts on rod spine on the FAQs page for more information.

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Thanks TOM!
I did read before posting, but my question was: Is it the same thing(straightest axis and spine) or is it something else. Or, because of physics they "match".
I also read that some manufacturers sell their blanks marked (spine), so i thought SAGE could be one of them.
Some how, the strongest curve is usually on the white dots line.

To complicate my-self a bit more, say an XP-4 piece blank, where would most builders put the guides?

Thanks for the input.

The spine is rarely in line with the blank's natural curve. Nor are the stiffest and softest axis's normally 180 degrees apart from each other.

The stiffest axis of any blank is usually found along the outside of the blank's natural curve. This is not the spine, nor is it the opposite of the spine.

The spine will be found to be the softest axis of the blank and can be located by pressuring the blank and allowing the blank to rotate to point where it naturally wants to locate itself and come to rest. In this pressured position it will "stay put" and will resist any effort on your part to roll it out of this position. We mark the outside of that curve(for reference purposes) and call it the effective spine.

Most builders will locate the effective spine either on top or on bottom of a fly rod. Many get excellent results locating the effective spine on the bottom and thus putting the guides on the effective spine. Not that this is the only correct way, but it is one way to do it and seems to provide good performance.

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That was the term I was looking for, waiting for someone to explain this and the differences between all other terms such as Soft axis, Weak side, so long so on.
I guess that´s why I understand now the findings:

-" Usually I found the "weak side" almost opposite to the white dot´s line."-

THANKS a lot, TOM!!!

Hola hermana, How have you been? Want to read something stupid. I rewrapped an old Kennedy-Fisher rod that I made for my son around '83. When I went to put the color preserver I picked a bottle of Flex Coat CP and noticed that it was crystal clear. I thought that perhaps it a new product. I usually buy several bottles at a time. I applied the CP and tonight while appling the epoxy I noticed something strange. There was no CP on the threads. Then I realized that recently I had washed the bottle and left water in it. Maybe I am too old for rodbuilding anymore. Anyway the rod still looks good, looks like an Orvis wrap.