Don Adams Archery Spine Tester

[cedarshaft]

I have a Don Adams spine checker that will be used at my club, but am unsure of exactly how to decipher the info. It has deflection #'s and bow weight #'s. I checked a 1535 GoldTip that read about 500 for the deflection and 50-52 for the bow weight. I normally shoot the 1535 in my 40-45# bows. Any info or help would be appreciated.

[Ari_Bonn]

Are you using the correct weight? I know the weight is different for carbons than woodies.

Also I may be mistaken but I think carbons are measured at 28" while woodies like that tested is meant for is spaced at 26"

[Tyler C. Moore]

That measurement is right on for woodies. The Adams uses a 2 pound weight evenly between 26" posts. Once you go out to 28" the weight needed drops slightly.

I love my Adams, and I just checked a few beeman ics bowhunter 500's and for #50-52

[Orion]

Right, the Adams is meant to test wood spines -- 2# weight hung in the middle of the shaft suspended on posts 26 inches apart.  Carbon arrows are spined using Easton's parameters, a 1.94# weight on a shaft suspended on posts 28 inches apart.  They yield considerably different results. Your Gold tip designation 15/35 was derived using the Easton parameters.  

I did see a conversion chart somewhere on the internet.  Might be able to find it if you search for it. Good luck.

[Cupcake]

You can download a paper on converting between the two measurement systems and also some conversion charts to translate between the two systems.

It is really simple in the end.  If you know the aluminum or carbon deflection in that system just multiply it by 0.825 to get the deflection in the wood system; then divide this result into 26 to get wood spine.

A 600 carbon arrow works out to 52.5 pounds spine.

[Cupcake]

Oops, forgot website:
 www.oakcreekarchery.com

[Captain*Kirk]

Thanks for the link. A very precise, yet expensive tool for the home arrowsmith...
In the end, "actual spine" is only relative as a starting point for what should be right for any particular bow/arrow combo. Once you have dialed in what works best in your case,(via trial and error, bareshafting, paper-tuning etc) the only factor that matters is sticking to the consistency of that spec, not the actual spine number you arrive at. In that case, any home-brewed method you cook up to ensure all arrows arrive at the same place with garner the same results regardless of any number.