Got this info from Grim and South Shore Rat on Crossbow nation .
Here is what I put together and why I did it.
I use my RAM spine tester to find the stiff side of the shaft first I install a mark on the shaft. Next I put the shaft in my flo tester with my laser light. I have a degree wheel on top of the tester and a laser so I can install the shaft mark @ 0 on the degree wheel. using the plunger to push the same each time and then watch the laser light to fine tone where I want to install the cock vane. I have had the RAM tester a few months now and if you are building your own arrows and done have one but your shafts from someone that does so they can mark the shafts for you. If your in Canada I know BOO can do that for you . I the USA I know Jerry South Shore Archery marks them. They both have great prices and are second to no one .
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