goldenarm

I'm looking for info about tesing the spine of shafts.I know that it is more into the trad bows with the wood shafts, but I'm wondering about carbon and aluminum shafts .I made one with all the bells and whistles,it has roller bearings on the ends ,a 2pd weight that is 2 pds,a dail indicator.Ive seen some of these set at 28" and some made at 26". I made mine so I can move them to either setting. What I have seen so far just playing with it when you turn the shaft you have to grab it lightly cause the amount of pressure you put on it shows up on the indicator.The biggest ???? that I have is how do you want the stiffest part of the shaft in relation to your nock alignment??.If you are shooting compound or recurve ,does the nock stay in the same position or do you have to rotate it??So the stiffest part shelf or the riser??Any help I would greatly appriciate it thanks for your time

lpv77

I always wondered about that myself. I have built fishing rods before and have always had to wrap the guides in relation to the spine for optimal performance. I wondered if it applied to arrows.

Straightarrow

A spine tester is very useful. I made one for myself, and use it frequently. I use it first, to sort the dozen into usable and not useable shafts. This will not apply to some arrows, which are very consistant (aluminums and some carbons). Many carbons will have a great variance between the stiffest shaft in the bunch, and the weakest. This has convinced me that many of the lower priced arrows, may be the cheapest, but they are not always the best deal. Those with a great variance must be culled. I personally want to keep them all within .010. This is not easy to do on many of the arrows out there.

Second, I test each shaft to find the stiffest side. I mark it, and then put the cock feather on that mark. By doing this, I've been able to tune a group of carbons to shoot surprisingly similar. I have found this to work especially well for arrows where I'm using broadheads.

If you do a search, you should find a few threads showing some homemade testers that some have posted about.