I just bought another dozen shafts and I really want to make these a very close set. I bought a digital grain scale and have weighed each shaft. Out of a dozen, there were only two arrows that were 2 grains heavier. Not bad for Gold Tip XT's.

Anyway, I also want to find the spine of each arrow and fletch them accordingly. I've read about floating them and other gizmos that can be made to do this. Tonight, I had a thought and wanted to check it. I pulled the nock out of an arrow and using a flashlight, you can definitely see a seem inside the shaft. Would this be the spine or stiffest part of a shaft?

Maybe I am going way overboard with this stuff (can you say addiction?) but I've read enough about this sort of thing and how it really does make a difference. So, I thought I've give it a shot with this dozen.

Any insight on this"?