Question on Stu's calculator

[Gregg S]

I find that when I enter a named recurve and then add the adjustment for the side plate I come up with a bit different Required spine number then if I enter generic recurve and then do the math and enter the actual measurement of center shot. If I adjust the calibration number to match the set up for a known bow the numbers come out very close. Do you use the preset named bows or do you use generic and enter your own numbers?    This sounds a bit confusing after rereading my post. I hope that it isn't too bad. Any thoughts?

[Swamp Yankee]

When you use the named recurve, the calculator automatically enters the correct center shot measurement, but you have to enter the correct plate thickness.

[Gregg S]

Yes I did enter the correct side plate measurement when using the "named recurve". It comes out a different number though when compared to using the generic recurve and then figuring the actual center shot. I used a set of calipers to make my measurements. Just wondering if most of you just use the preset named bows or find that it is more accurate to enter the measurements of that bow itself?

[jcar315]

I use the name provided in the calculator.

[Shawn Leonard]

Don't use it, or if ya do pick an arrow spine at least 15#s less than it suggests. Has everyone overspined! Shawn

[MikeW]

Originally posted by Shawn Leonard:
Don't use it, or if ya do pick an arrow spine at least 15#s less than it suggests. Has everyone overspined! Shawn

Can't give what is going to work for my bow yet but STU's is telling me a 340 for my bow cut at 29"BOP with 250 grains up front and I have some 340's at 32.5 and with 300 grains up front they are too stiff. I'd say Shawn knows what he is talking about.

[cedar]

Must be about the same as the Easton arrow charts.  I go two or three blocks weaker in spine than they suggest also.

[Gregg S]

If I leave the calibration set at 0 it shows me needing an arrow of 9 lbs. heavier spine from a 40# bow. However if I set the calibration to match a know set up then it shows the same number. 1/16 difference in the measurement of the strike plate results in about a 4# difference in the spine required.

[CEO]

Agree with Shawn, except I'd say at least 20# less.

[Gregg S]

Shawn. Did you recalibrate the calculator for your shooting style using a known setup? And it still showed 15#'s heavier then needed?

[xtrema312]

Originally posted by CEO:
Agree with Shawn, except I'd say at least 20# less.

For carbon I agree and while you are at it try -25# for a starting spot so you can cut a little just to be sure.  Most of mine are running around -20# on 400 or 5575 spine carbon.  Other than that it is consistent and I can get real close with different carbon arrow set-ups.

I don't know about wood and aluminum.  I kind of think it is real close for those based on comments I have seen and old rules of thumb and charts.