Spine Indexer

[Terran28]

I am making a homemade spine indexer and have all the equipment I need. However, everything I am reading online says for spacing that 28" is what is used for carbon arrows (given that new arrows uncut are 30-31"). My issue is I have precut arrows and do not build my own yet (27.5" from nock throat to insert). Can I get away with a 26" spacing and dial indicator at 13" just to find the strongest part of the spine? I am not interested in true spine deflection, just spine indexing (and doubles as an arrow spinner for straightness of broadheads).

[Low Fence]

I am making a homemade spine indexer and have all the equipment I need. However, everything I am reading online says for spacing that 28" is what is used for carbon arrows (given that new arrows uncut are 30-31"). My issue is I have precut arrows and do not build my own yet (27.5" from nock throat to insert). Can I get away with a 26" spacing and dial indicator at 13" just to find the strongest part of the spine? I am not interested in true spine deflection, just spine indexing (and doubles as an arrow spinner for straightness of broadheads).

Sure

You won’t get the actual spine reading but will find the stiff side reguardless

[Briar Friar]

Very cool venture Terran.

Post some pics of your setup when youve time. Good luck!

[muddyfuzzy]

you are on the right track for what you are wanting to see.

[Terran28]

Thank you guys. I forgot about the 2 pound weight. I can't make my uprights until I figure that out. Most likely will have to be a fishing sinker of some sort, which means next week on payday. My father-in-law that I live with has a wood shop and a home made CNC mill. The uprights will be done on that so they are exactly the same with precise holes for the bearings drilled.

[enewman]

just shoot them to index. testers are ok, but are not the best way.

here is why.

arrows have a reaction when shooting. what you are doing with a tester is trying to find a point so when you shoot them they will all react the same. problem is when you add tip weight that can go out the window.

also where do you place this point you are finding. 12:00 9:00 3:00 or at 6:00. you can have a different reaction at every location.

[enewman]

here is a few examples. i found the point i would call least amount of deflection with the indicator. this point is called 0. here is what the arrows looked like being shot with the 0 mark set at 12:00

[enewman]

here is at 270 degrees. now I wrote 270 degrees to keep it simple. not all arrows did I find this point at 270 degrees. by the way, I used a tester called a PAPS to locate these points

[enewman]

now all of that is with a 125gr tip. if I increase tip weight it will all change.

I'm not saying don't build a tester. by all means, build it. it is still a tool. but build it so you can pull down on the arrow, or build a 3 lb weight or so for it. the more weight the easier it is to find these locations you are looking for.

[Rat]

here is at 270 degrees. now I wrote 270 degrees to keep it simple. not all arrows did I find this point at 270 degrees. by the way, I used a tester called a PAPS to locate these points

Is this the first shot out of the PAPS? If so, that's pretty danged impressive!

That sure would cut down on my arrow tuning time.

[enewman]

Is this the first shot out of the PAPS? If so, that's pretty danged impressive!

That sure would cut down on my arrow tuning time.

I did the test every 90°. In the paper I break things down.

[Loneaggie]

Won't hurt, but enewman is also right I think. The indexer will help, it won't hurt, but in the end how they come out of the bow trumps everything. Its one of the things I kinda wish I had a Hooter Shooter for. Between that and calibrating a torque indicator, makes me wonder....