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

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.

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

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.

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

Mike