designing draw weight question...

[Scrub_buck]

Can anyone give me some rule-of-thumb guidelines as to how thick (from belly to back) the limbs need to be for a 66" osage flatbow design to draw 45-55 pounds. 

The flare is going to be about 1.5 inches at the widest part of the limb (about 2 inches from the handle) .. and I hope to slowly taper the limb width to about .5 inches at the nocks.  I hope to get the bow to draw 27.5 - 28 inches ... that's my draw lenght.

Can this info be had, or is it just a metter of floor tillering and 'feel'?

Sandy

[Jmilbrandt]

I would just cut it to just over a half inch thick and then floor tiller it from there. If you don't feel confident enough going that close go a little thicker. There is no set thickness on the limbs you just have to floor tiller it and go from there.

[JackCrafty]

Just ask someone who has an osage bow that has the same dimensions as the one you want to build.  Of course, you'll get slightly different answers from everyone.

The half-inch guideline is good, though.

If you want written formulas, get the Bowyer's Bible Series.

[Badger]

   I have never seen a written formula anywhere for thickness, not one that was worth using anyway. Steve

[Marc St Louis]

You would want at least 5/8" thick to start with at the fades

[Hillbilly]

Every piece of wood is different in density and elasticity, so you can't really set meaurements. I would probably start out something like 5/8" thick at the fades, 1/2" at midlimb, and 3/8" at the tips and go from there buy how it's bending. You can take more wood off, but you can't put it back on.

[George Tsoukalas]

Nope. All wood is different even within the same species. Sometimes I start at 3/4 in. at the end of the fades and about 1/2 down from the nocks and  draw a line. Floor tiller, long string tiller and tiller  from there. Mostly I just wing it and don't draw lines for thickness tapering. As a beginner I came in underweight more often than not. Jawge

[Scrub_buck]

Thanks for the help guys!

[Pappy]

Like the others have said 1/2 to 5/8 usually will do what you want to start with. If you are doing a pryamid design I usually don't try and tapper the limb thickness to start with,just floor tiller and get the limbs bending even.When I floor tiller I don't try and get it bending to easy,if you do it is easy to have it to close to weight and not enough left to tiller out without missing weight.
Pappy

[GregB]

I'm in the ballpark with what everyone else has said. If I'm maintaining limb width to midlimb, I'll go 9/16" a couple inches out of the fades down to 7/16" midlimb, then maintain the 7/16" to the tips. That's usually is a good starting point for floor tillering.