Need Wood Spine Suggestions.

[Wannabe1]

Want to shoot woodies from my Black Widow PL II. It is 62" and pulls 45# @ my 29". What spine would you folks suggest with it being Fast Flite and center cut?

[Shaun]

65/70

[Butch Speer]

Shaun,
I've never understood the process of picking the proper spine. Why 65/70? Not that I disbelieve you for sure. Just don't understand. Thanks for any info.

[celticknot]

Butch Speer, I would also say 65 70 because they spine out wood arrows at 26 inches plus bows are faster than what they used to be. The arrow flexes more with speed and you have to compensate the 3 inches that you add to the arrow with your draw length that will wmake it weaker. You should beable to have a 30" long arrow maybe longer if you start with that spine.

[snag]

TW, what tip weight are you wanting to shoot?

[Wannabe1]

David, I was looking to shoot 135gr.

[Butch Speer]

Celticknot,
Thanks. I just never considered the 26in. part. Makes much more sense now.

[moebow]

Celticknot,Butch Speer,

To clarify the spine measuring issue... Wood spine is MEASURED between 26" centers with a 2# weight.  That deflection produces the shaft's spine rating for 28"  TWENTY EIGHT inch arrows.

[reddogge]

moebow is right, the 26" measurement is just an industry standard to test the deflection for a 28" arrow.  You then compare the deflection to a spine chart to see what spine it is and then start adding for longer arrow, ff string, recurve bow, heavier point weights, etc.

Here is a starting point.
http://www.3riversarchery.com/pdf/WoodChart.pdf

I can't find my link to the Kelly spine chart if anyone has it.

[snag]

TW, I would try some 65# at 30"bop for the 135gr. tips. You could go to 150gr. tips with 65# for 29.5"bop also. Of course this is just a starting point for tuning. I have some made up if you want a couple to try out...pm me with your mailing address and I'll get them out this week to you....?  

[LBR]

Ballpark would be 60-65 or 65-70's.  Here's why.

Actual draw weight - 45# - 45# spine

29" draw - add 5# spine for every inch past 28"=50# spine

shelf cut past center - add at least 5# spine=55# spine

"Fast Flight" type string - typically add 5# spine=60# spine

135 grain point - add 5# spine for every 10 grains or so over 125 (subtract for lighter points)= 65# spine

If you go with a hardwood shaft that is extra heavy (ash, maple, hickory, etc.) you may need to go another 5-10# heavier in spine.

That's just a ball-park calculator.  There's lots more variables--how the string was made, your release, bow performance, etc.

It seems the better your form and release are, the wider the spine range you can get away with, and the lower you can go with spine.

Like most things, it will take some tinkering on your part to figure out what works best for your set-up.

Chad

[LBR]

Almost forgot--for every inch you cut your arrow past 28" (BOP), typically add 5# to the spine.

Chad

[Bill Carlsen]

65-70 should do it but even 70-75 might be better.

[Jake Fr]

wow i'm glad i read this couse i never knew that

[Wannabe1]

Wow! Thanks for all the info folks. Snag is going to send me a couple of test shafts to play around with. I'll let you all know the out come in a new post.

Once again, just a world of knowledge and willingness to share. That's why I keep coming home!