28" or 26" Spine Tester?

[kirkbow]

I'm making a spine tester but which one would be best to build?

I could make one long enough that i could have 26" or 28" supports and have a 1.94# (31 oz.) weight and just add an ounce for the 26" test.

I currently have some carbon arrows and that is what i'll probably be shooting. Although i may shoot some bamboo in the future.

Uh, why two standards?

Thanks for your advice experience ahead of time.
Kirk

[kirkbow]

Another question, when building a dial indicator tester how is the tension of the spring on the caliper accounted for?

Thanks,
Kirk

If you are planning on usung wood arows, I would go with 26" and a 2# weight. All I shoot is carbon and mine is a commercial made, 28" and 1.94# weight.

Unless you are spine testing for other folks it really does not matter which way you go. If all you are doing is your own shafts then you are looking for a consistency in your shafts and that is it.

As far as the spring tension on the caliper goes, the one on mine is VERY, VERY light. Mine measures in thousandths of an inch and is very sensitive. I doubt the spring in mine changes much of the outcome.

Bisch

[AkDan]

you can go both...but I'd also go with the 26" centers and 2lb weight.   And than start testing known mediums.  Theirs a few guys with deflection charts for aluminums so you can calibrate your chart.  I can never remember the formula though.  

I use an Agincourt archery spine tester.   Much less headache to buy the thing than it was to build one imho.  

I'm curious though why you want a spine tester for shooting carbons.  They're already spot on and testing them will really gain you nothing.   If you plan on switching to wood or visa versa you can use these numbers to get you on fast...otherwise its a tool you'll never use atleast for carbon/alum.  

Why two standards...you can thank Easton for the 28" and 1.5lb test.  Never understood it other than to be different.   They've also managed to up wood shaft prices substantially when they went after the excise tax on arrows built overseas.

[TOEJAMMER]

My experience with carbons, irrespective of what manufacturer, is they do not have much consistency in spine although they are touted to be +/- 2#.   It isn't my gut feeling as I have tested them on three different spine testers: Adams, Schieb and a dial caliper.