limb thickness for the correct pounds.

[Cherry Tree]

Hey guys, im making a R/D longbow 54" long im wanting it to be between 25 to 30# @ 24" draw. It will be a small petite bow. Im hoping someone can get me in the ball park of the thickness of the laminations and glass. I know the width of the limb and length of riser will play a role in this but I need a ball park best you can give.

Thank you for your time.

[Bowjunkie]

Are you talking about making a glass/wood laminated bow?

[Cherry Tree]

Yeah fiberglass with wood laminations in between.

[jess stuart]

I have built several 50" longbows for kids.  I used a 12" riser, .040 glass and a total stack of about .250 this was for a one inch wide bow, I usually get about 20# @ 20".  I know not to much help, you will probably just have to guess on the first and adjust on the second and there will be a second and probably many more.

[KenH]

As a S.W.A.G.  I'd say Jess is pretty close for a 1" to 1.5" wide , 50-ish long straight bow depending on the degree of taper to the limbs.  I build bendy handle flatbows of about those dimensions and draw weights, using approximately that stack thickness -- .040 x 2 glass, plus .04 or .05 x 2 wood lams between.  Mine don't even use a riser really, just an extra 12" length of .04 or .05 wood between the other two wood lams

[Cherry Tree]

No one on here has made 54" longbows?

[kennym]

I built a 50" D/R that came out at 24# @ 22"

2 - .030 glass
2 - .020 veneer
1 - .090 x .002 pi taper
1 - .050 x .001 pi taper

Total stack @ .240

Riser length - 14"

1.25" wide at fades

Just scaled down the profile of my 58" D/R

Sent the form home with David Flanrey, maybe he has built a couple off it.......

Hope that helps!

[LittleBen]

If you need to hit weight on the first try you're going to need to build a design that already exists and comes with stack information.

Not to be crass but this is impossible to answer without having more information. What's the riser length? What's the width? Is it straight limb or RD? Tapered lams or parallel? And even with all that, you are probably gonna end up making at least two to get there.

For example, I have a 54" recurve that's 2" wide, and 50#@28"' about 40# @24" I'd guess, and the stack is only .190", and that's all parallel lams.

When you're talking about stack thicknesses that low, small changes make a big difference. For example, Going from .200" to .160 will cut draw weight nearly in half.

If you're building a bow like Jess described, just stretching to 54" long, and keeping 1" width, you're probably somewhere in the ballpark of .260-.270". I think for the best chance I'd build it 1.5" wide and say .260" stack, and narrow from the to get your weight. Even then it's basically a crap shoot.

[Cherry Tree]

Thanks kenny thats what I was looking for!

Little Ben
Your right its a shot in the dark but getting information like kenny shared its something to work from. Im well aware of what little things can change the weight of a bow.

Thanks for your time.

[JamesV]

54" R/D Longbow 1" wide: 14" riser, .005 taper,
.040 glass Total Stack .260, 25# @ 26.

James

[Cherry Tree]

Thanks James!