Mathews Inc.
Carbon arrow cutting for spine
Equipment
Contributors to this thread:
Bowfreak 15-Mar-19
nvgoat 15-Mar-19
wildwilderness 15-Mar-19
4blade 15-Mar-19
JTV 15-Mar-19
SBH 15-Mar-19
4blade 15-Mar-19
Bou'bound 16-Mar-19
BTM 16-Mar-19
From: Bowfreak
15-Mar-19
Just curious if there is a rule of thumb for cutting carbon arrows? It seems that I read in the past on some trad site that cutting an inch off your arrow is equivalent to removing around 35 grains of point weight? I assume this was for wood shafts but didn't know if that held true with carbon. If you had a setup that you know was weak and that by removing 50 grains of point weight it tunes perfectly, how much arrow would you need to cut to stiffen the shaft so you could keep the extra 50 grains of point weight?

From: nvgoat
15-Mar-19
You might check one of the online archery software sites. I have Pinwheel as it could be used with a Mac when I got it. Archers Advantage may have similar info.

You can enter your bow specs and arrow specs to see the spine. Then you can adjust arrow length, point weight, insert weight, etc to see what effect that will have. From there I then bare shaft tune and have had great results. I have found this very useful. The old charts like Eastons aren't that helpful.

15-Mar-19

wildwilderness's Link
You need a dynamic spine calculator.

see the link for a easy free one, Stu Miller

http://heilakka.com/stumiller/

From: 4blade
15-Mar-19
I have found over the years that 3/4" is equal to 25grs of head weight with carbon arrows. So cut 3/4" and raise point weight by 25grs to come out where you started. So the answer to your question for 50 grs is to cut an 1 1/2".

From: JTV
15-Mar-19
Ive cut my arrows and customers arrows 1 inch to 1.5 inch in front of the rest.. with a drop a way, in the up position, or a biscuit in front of the bristles .. I do this with full capture style rests.... traditional bows are cut in front of the riser .... there is no reason I find to go longer ... I have a 30" draw, and shoot a 27.75" arrow using a Biscuit .... BTW, draw length has NOTHING to do with arrow length .... it all has to do with how and where the rest is set up .. cutting shorter will increase spine if you have the length to do so .....

From: SBH
15-Mar-19
OP is asking about spine changing not weight.....at least that's how I read it. If your arrow is 10 GPI...wouldnt cutting 1 inch off lose 10grs? How are you guys getting 50grains off with an 1 1/2". I don't know of any arrow that are much heavier than 11-12gpi.

From: 4blade
15-Mar-19
SBH, read it again. He's asking about point weight, not arrow weight. He wants to keep that 150gr head but as it stands now the arrow spine is to weak. Cutting an 1 1/2" will stiffen the shaft so it flies right with 150grs of point weight. Yes you lose 10 grs on the arrow shaft but shortening the arrow stiffens the spine so he can use a heavier point weight. Quite frankly, if it was me, I would probably cut an inch and shoot the bare shaft first. If its still to weak, cut the other 1/2".

From: Bou'bound
16-Mar-19
Measure once cut twice

From: BTM
16-Mar-19
LOL Bou! Now I know why I my weekend carpentry projects cost so much! :)

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