How do you find the AMO Static spine of a arrow? I have looked at Stu's instructions and so one and just making sure that I am correct.
Ex on a .400 spine arrow
Thanks Guys!
Carbon and aluminum arrows are measured on 28" centers for their static spine.Wood is measured on 26" centers.What do you mean by AMO static spine? I have heard of AMO used for a bows length but not for arrows.
Take any ASTM spine number and divide that by .825 will give you the actual AMO spine
"They report spine numbers based on an ASTM standard using 1.94# @ 28" centers.
Convert ATSM spine to AMO spine by dividing by 0.825."
So your .400 divided by .825 gives you .48484848484 lbs amo spine or 48 lbs.
Huh? Your conversion gives you a .48 deflection, which is equal to a 65# spine. A .400 deflection using a 2# weight at 26 inches also spine 65#.
On the other hand, the numbers written on carbon arrows may or may not reflect the true deflection/spine. I have some Easton Axis N fused with the number 400 written on them that spine 80#. My Gold Tip 55/75s actually spine 85#. Go figure. :dunno:
Sorry for the typo, but you are right. That number is the amo deflection number, not pounds.
.400 spine should be 78.8#
use the yellow box on Stu's calc.
Eric