I never really post to forums, but I thought I would jump in here on the spine testing. (I designed and built the RAM carbon QC back in the day, so some of my info is dated and not fresh in the memory banks) I have found some arrows that showed perceived variation in straightness and spine in the label, it depends on the process used to print the label; for instance some of the early silk screens were .003-.005 high, especially if it overlapped where it came around the shaft. I would also see a bit of disturbance down the full length of the arrow on some of the old full camo carbon arrows where the camo wrap came together. However, I think the majority of arrow decoration is now done with dye sublimation and has negligible thickness. As far as spine consistency down the length of the arrow, that usually depends on the method of construction. An aluminum arrow will show a slight uniform spine high spot down the length correlating with the weld (unless the arrow was made by the process of drawing over mandrel or DOM, which I believe Eason went away from in the late 90's). You may see the same effect on aluminum carbon composites but it will be nearly too slight to measure. Carbon tech has a proprietary manufacturing method the yielded near perfect spine rotationally and axially. Wrapped carbon shafts such as gold tip used to show a marked spine high spot, that I attributed to where the edges of the pre-preg came together, but it seems to have gotten much better of the last ten years, to the point that I rarely spine check anymore unless I am setting up arrows for fixed blade broadheads, and even then I generally just build, shoot and rotate nocks until they all fall in an acceptable group, either by hand or with a hooter shooter.
