Question for the woodie experts

[shortstroke 91]

If you have a full length 32" wood shaft that spines out at #45 and you start cutting off inches how much does the spine go up with every inch cut and is it linear or does it change with every inch? I.E. is the first inch worth #3 and the next #5 and the next #7 or is each inch equal?

[Grey Taylor]

That #45 is for a 28" shaft.
Unless I'm mistaken, it's about #5 per inch. With a 125 gr tip your 32" shaft should have an effective spine of something like #25.
The change in spine is linear.

Guy

[Bud B.]

Guy hit it.

I think they are spined at 26", so a full 32" shaft will act weaker at the full length. As you cut, it gets closer to actual spine the shorter you get.

If I remember correctly, spine needed will increase 3-5 lbs for every inch past 28".

A full length 45lb spined arrow will be somewhere in the upper 20s or lower 30s in dynamic spine depending on fletching and point weight and also bow weight.

[shortstroke 91]

Here's why I ask. I have a center cut longbow with a simple calf hair rest, with a 6 strand skinny string, #47 at my 29.5" and it shoots a 30.5" #42 shaft perfectly. Here's the kicker it's got a 190 grain head and 3 4" feathers (total weight is 550 grains and I'm getting 160+ fps). This arrow should be so underspined that I'd be afraid it would blow up on me but they shoot great. I started with #65 and they shot stiff, moved down to #55 and still too stiff finally went to #40-45 and with field points and broadheads they're right on the button. It goes against everything I've ever been told with wood shafts and I can't figure out why.
According to Stu's chart they're only #24 but they fly so good I'm scratching my head....  

[Teacher_of_the_Arcane]

Hey.....that reminds me....I've got four dozen 32" shafts in the shop that need my attention!  I hope they shoot as well !!

[WESTBROOK]

Your right, dont make sense.

But the way I look at it, if they fly, gimme a dozen just like'em.

Eric

[jacobsladder]

Your bow may not be cut exactly to center...then adding the calf hair bumps it out....so u could possibly be 1/8 shy of center..11/32 diameter arrow bumps it out further...just tossing some possibilities out

If your bow likes them and the 4" feathers are controlling a broadhead....I say shoot them