Spine Calculator - Negative Dynamic Spine?

[akbowbender]

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

[timbermoose]

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.

[Hermon]

When you say "0.58" deflection do you mean that the shafts spine at 58# ?  If so, type in "58" rather than "0.58".

[akbowbender]

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.

[wingnut]

Yep it asks for the static spine of the shaft in pounds.

Mike