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Main Boards => PowWow => Topic started by: akbowbender on December 31, 2014, 04:25:00 PM

Title: Spine Calculator - Negative Dynamic Spine?
Post by: akbowbender on December 31, 2014, 04:25:00 PM
I'm tinkering around with spine calculuators, Stu's and 3R, and I'm coming up with a negative dynamic spine on both.

I select Wood Arrow and use a 0.58 AMO deflection, 11 gpi for an 11/32" shaft. I input a 28" shaft, 145 gn point, 0 insert, no footing, 10 gn nock and 3-5" feathers and get an -11.1# dynamic spine.

I could bother Stu with this, but I was hoping some here would know what is going on. I used it on a 2016 shaft just to make sure the program was working (I'm using Open Office Calc), and it seems to be o.k.

Thanks
Title: Re: Spine Calculator - Negative Dynamic Spine?
Post by: timbermoose on December 31, 2014, 04:29:00 PM
Think you have to put in the spine. In pounds. If you putting in .58, then it thinks your shafts are spined to .58#. Least that's what I gather.
Title: Re: Spine Calculator - Negative Dynamic Spine?
Post by: Hermon on December 31, 2014, 04:33:00 PM
When you say "0.58" deflection do you mean that the shafts spine at 58# ?  If so, type in "58" rather than "0.58".
Title: Re: Spine Calculator - Negative Dynamic Spine?
Post by: akbowbender on December 31, 2014, 04:45:00 PM
Thanks.

I thought that the number they were looking for in that field was the spine deflection number, no the #'s. The deflection number I was using equates to 44.8 lbs., which is works for this exercise.
Title: Re: Spine Calculator - Negative Dynamic Spine?
Post by: wingnut on December 31, 2014, 04:57:00 PM
Yep it asks for the static spine of the shaft in pounds.

Mike