Can anyone tell me how to spine-test wood arrow shafts less than 28"? Is there some mathematical derivation to use? {my dial-indicator spine tester has uprights fixed at 26"}
I've heard, "Oh they're just kid's arrows, it doesn't matter, they'll be so stiff yada-yada-yada..."
Well buggers, don't they deserve something better than curtain rods? :help:
If you spine them at 26 inches, you'll be close enough. 30-35# is about as low as you will find in 5/16 cedar shafts. That generally works pretty well when you cut them to 26 or even 24 inches. At those lengths, the dynamic spine will be heavier, of course, but most will still shoot well at kids draw weights of 30# or so give or take a few pounds.
The portion of the arrow that is sticking out past the 26 inch supports has no affect on the spine you measure. If the arrows you are measuring will be supported by your tester at 26 inch span the spine you measure will be valid for any length arrow greater than 26 inches.
If you need to spine shorter shafts and can make supports closer together on your tester I can calculate a conversion for you for the new span.
Kevin
Thanks, Orion & Cupcake.
I have some 5/16" POC's and some won't even hold up a two-pound weight @ 26" centres.
Maybe static spine is a moot point with kid's arrows at say 24" length & low poundage bows? Dunno. However, I am concerned about wood arrow safety and I'd feel better if I have a sense of the static spines. I'm in new territory here.
Been there done that. My son didn't really get good until I got him some good arrows.(he's won the NC state twice and ATAR once) By good arrows I mean aluminum not wood. I never could get any wood arrows to fly right out of his bows. Of course I was using 1/4" ramin so I shouldn't have expected much. 5/16" inch arrows would have still been too long to get the proper spine and they were hard to keep straight. Also, they would never stick in a target. I ended up going with Easton Jazz arrows. I'd use the chart and based on my experience I could pick one close enough to work and vary the point weight if I need it weaker. Since he was 8 he has only shot two arrows, 1413's and now 1516's at age 12. I doubt either of those could be spined with a 2# weight. If you don't want to handicap kids try some aluminums. You can usually get some used ones on the net for cheap. That's how I got my son's. Keep your eyes open on the other archery site for target (FITA) arrows. They usually come in low spines.
If you're talking about young kids (under 10 or 11) and light kids bows (under 30lbs at their draw length) I think your wasting your time worrying about spine. Let them fling away, coach a little but don;t expect perfection.
Arrow spine for kids is just as important as it is for adults. An arrow that is too light in spine will never shoot right for any bow, and may even be dangerous. We separate 24" x 1/4" ramin arrows into 3 groups based on stiffness. The stiffer 1/3rd shoots good from bows 20# @ 22" and up to 40# @ 28", when drawn up to 24" The middle group works for 15# bows, and the lightest group works for 10# bows.
An arrow is only as good as the effort used to make it. If you don't want to see your kids discouraged because of poor performing equipment; put some effort into matching the bow to the child, and the arrows to the bow.
Chuck Jones