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Main Boards => The Bowyer's Bench => Topic started by: rkmnt2 on November 07, 2008, 12:27:00 PM
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I want to build my daughter a longbow. I have a model that I want to copy but it's much heavier than the one I want to make for her. So how do I come up with the lam thickness's and taper rates other than just trial and error? Could get a little costly. If there isn't a formula or chart that I could get my hands on....how bout your best guess?
60" with a slight R/D. About 35-40# @ 27".
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60" with a slight R/D off my form-
15" riser,1.5" wide at fades to 9/16" wide at nock ,.002"taper is 52# @ 28" at 340". 60# is .350"
My guess without seein your form is .315"!! LOL
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binghams catalog has a pretty decent chart in the back of it. You'll have to pay a few bucks to get it but its been a decent reference. Also kenny has been just as good for lam specs. two sources couldn't hurt. kennys spec seem to my limited experience to be pretty close.
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Here is their chart,its hidden in the FAQ section!! LOL
Don't think they have a one-pc r/d tho......
http://www.binghamprojects.com/drawweight.htm
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I think I've got a pretty good idea of where I'm going with this. The first one is going to need a little fine tuning to get it close but eventually it'll be a piece o cake....right? lol
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I would try something around .334”
That is 2 pcs. .040” glass
3 parallels @ .050”
and 1 taper @ .104” (.002)
I came up with those numbers after a lot of thought and research...
62" Delfex/Reflex one piece longbow
18" riser
shooting for 45# @ 28"
Good luck, I plan to build this bow when other things slow down...
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As you can see my numbers and Kenny's are pretty close even with his bow being 2" shorter and the riser being 3" shorter.
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Nice! Now that brings me to another question. You both spec out .002 taper. Why....or why not?
Dustin. Is the width of yours similar to Kenny's too?
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Width would be the same...I think a .002 taper will make for a smoother arc in the limbs. Smooth arc = less stress.
On the width you can start wide and then decrease if poundage needs to be dropped.
Remember these glass bows are tillered from the sides..
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I have a chart I was building, I'll have to find it. But it had pics of bows with the specs and the final poundage of said bows.
If I come across it I'll send you a copy.
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That would be cool. Thanks.
And congratulations on winning Kenny's lams. That makes another project a little easier to start!
Don
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Thanks, it sure does..I have a Possibles bag build along I need to post..will be starting a plains style quiver on Monday...Have to build another bow can't let Kenny's lams sit around..and a million other things.
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It is possible to make bow more longly on 4-6 " and trimming to receive the necessary force for lady. For 27 " she should be... big length.