Was just looking at buying one of these and you vid popped up in my feed. Thank you algorithm! And thank you good sir for a bit of good information! Subbed for sure
ATA, AMO, and ASTM ATA (AMO) is the Archery Trade Association, formerly the Archery Manufacturers and Merchants Organisation. When they measure the arrow spine, they record the deflection in thousandths of an inch. An arrow is attached to two supports, 26 inches apart, and pressed in the middle with a weight of 2 pounds (907 grams). A deflection in the arrow of 0.4 inches gives an arrow spine of 400. The arrow spines of wooden arrows are measured according to the ATA system. ASTM is the American Society for Testing and Materials. In their Test Nr. F2031-05, they record the deflection in thousandths of an inch. In this test, an arrow is attached to two supports, 28 inches apart, and pressed in the middle with a weight of 1.94 pounds (880 grams). The weight is smaller, but the distance between the supports is greater, which should give a similar deflection. Arrow spines of carbon fiber and aluminum shafts are specified according to the “modern” ASTM standard.
I made one, but am doing something wrong. It's measuring higher then what the spine is. It seems to me, the smaller the number (deflection), the the stiffer the spine, the larger the number the weaker the spine. If the deflection is 15, doesn't that show a weaker spine then if it deflects 10? The arrow is bending more, weaker.
I must be doing something wrong the math is coming out way off. I'm taking my measurement in cm and using a conversion calculator to mm and it shows nothing remotely close to the numbers im looking for, according to the video
Its just to get the hooks into solid wood and level. If you have to have a little room above the hooks for the ruler, this is because all arrow shafts are different diamiters and could accidentally run off the ruler if you went to close to the top.
Legendary Skulls the number printed on the shaft can vary from manufacturer to manufacture (in relation to real world measurements), and in cheaper arrows, even from shaft to shaft. Also, while not in the vid or description, 2 hears ago he posted a comment about the 26" and 28" requirements
Lol... wood shafts arent marked. If you have multiple different spines in wood shafts and they get mixed up then having a spine tester to check them is what gets accomplished... duh Its also useful when cutting arrows down to find the final modified spine.
Also 1.94 lbs for carbon and 2.0 lbs for wood. 28” for carbon and 26” for wood.
What about river cane and bamboo?
I Think this is pretty much the easyes way to find out the spine of an arrow. Thank you so much for sharing!
Exactly what i was looking for to de-mystify arrow spine so i can start building my own arrows. Thanks!
No worries buddy, just remember that this is only for wooden arrows. Modern arrows should be set 28" apart with a 1.94lbs weight
When you say this is only for wooden arrows, does that include bamboo/river cane arrows?
Was just looking at buying one of these and you vid popped up in my feed. Thank you algorithm! And thank you good sir for a bit of good information! Subbed for sure
I never wanted one bad enough to buy one, though now you've shown me how easy they are to make, I reckon I might just have a crack.
Thank you. Very useful.
Well done, now we use our $s on more tools and materials to build more bows and arrows
I would use one like this more for checking consistency of spine between arrow shafts.
Why does carbon use a lighter weight when the material is stiffer than wood
excellent video
Not a big deal but 2 lbs is 907 g not 906g
(Exact: 907.185 g)
Big help. Thanks !
Spine is determined at 28" not 26
ATA, AMO, and ASTM
ATA (AMO) is the Archery Trade Association, formerly the Archery Manufacturers and Merchants Organisation. When they measure the arrow spine, they record the deflection in thousandths of an inch. An arrow is attached to two supports, 26 inches apart, and pressed in the middle with a weight of 2 pounds (907 grams). A deflection in the arrow of 0.4 inches gives an arrow spine of 400. The arrow spines of wooden arrows are measured according to the ATA system.
ASTM is the American Society for Testing and Materials. In their Test Nr. F2031-05, they record the deflection in thousandths of an inch. In this test, an arrow is attached to two supports, 28 inches apart, and pressed in the middle with a weight of 1.94 pounds (880 grams). The weight is smaller, but the distance between the supports is greater, which should give a similar deflection. Arrow spines of carbon fiber and aluminum shafts are specified according to the “modern” ASTM standard.
Legendary Skulls so you know 28” for carbon and 26” for wood shafts. Hope this helps.
Thanks!
I made one, but am doing something wrong. It's measuring higher then what the spine is. It seems to me, the smaller the number (deflection), the the stiffer the spine, the larger the number the weaker the spine. If the deflection is 15, doesn't that show a weaker spine then if it deflects 10? The arrow is bending more, weaker.
I figured it out. You divide the deflection by 26 to get the poundage.
I must be doing something wrong the math is coming out way off. I'm taking my measurement in cm and using a conversion calculator to mm and it shows nothing remotely close to the numbers im looking for, according to the video
cm to mm is just divided by 10 or simply move the decimal point one digit.
So: 1.0 cm = 10 mm
& 10 cm = 100 mm
Mate, why 3centimeters down ??
Its just to get the hooks into solid wood and level. If you have to have a little room above the hooks for the ruler, this is because all arrow shafts are different diamiters and could accidentally run off the ruler if you went to close to the top.
are the mesurments the same regardless of the arrow length?
No but it shouldnt matter much if your arrow is in the 28-32 inch range
cup hook
The Spine of the arrow is printed on the shaft all u need to do is find the spine side to fletch it right so not sure what U were hoping to accomplish
Legendary Skulls the number printed on the shaft can vary from manufacturer to manufacture (in relation to real world measurements), and in cheaper arrows, even from shaft to shaft.
Also, while not in the vid or description, 2 hears ago he posted a comment about the 26" and 28" requirements
Lol... wood shafts arent marked. If you have multiple different spines in wood shafts and they get mixed up then having a spine tester to check them is what gets accomplished... duh
Its also useful when cutting arrows down to find the final modified spine.