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Main Boards => The Bowyer's Bench => Topic started by: razorsharptokill on January 08, 2011, 09:18:00 PM

Title: Bow design for 22" draw?
Post by: razorsharptokill on January 08, 2011, 09:18:00 PM
I have someone who needs a heavier bow and I'd like to build one for them. They are shooting a 30lb comet right now and I can tell that they can go up in poundage very soon.

To get 40lbs of draw at 22" of draw, what would be best a glass recurve or longbow?

I'm guessing that a bow that is 40 @22 would be around 58 @28?
Title: Re: Bow design for 22" draw?
Post by: KellyG on January 09, 2011, 11:50:00 AM
Ask bradford he did his kids bows for christmas 5 of them so I am sure one would be in this range.
Kelly
Title: Re: Bow design for 22" draw?
Post by: razorsharptokill on January 11, 2011, 09:13:00 AM
ttt
Title: Re: Bow design for 22" draw?
Post by: hova on January 11, 2011, 09:26:00 AM
i think depending on what youre making , you could easily get 40@22 out of a stickbow. sounds like a growing shooter , so stickbows would keep your future costs down too...
Title: Re: Bow design for 22" draw?
Post by: razorsharptokill on January 11, 2011, 11:03:00 AM
I guess what I'm asking is if a 55 @ 28" bow would be suitable for a small shooter with a 22-24" draw that wants to be able to hunt with our states 40lb minimum. Would it have enough stored energy to be adequately fast or have enough delivered foot lbs.
Title: Re: Bow design for 22" draw?
Post by: Shaun on January 11, 2011, 01:26:00 PM
40# @ 22" is a LOT less than 40# @ 28". I would not hunt anything larger than rabbits with this set up.

Native bows were often very short and were set up for efficiency at such short draw lengths with a "chest draw" instead of modern form.

A bow reaches max efficiency when draw length is close to the stacking point.

What is the limiting factor for this archer's draw weight and length?
Title: Re: Bow design for 22" draw?
Post by: hova on January 11, 2011, 04:13:00 PM
shaun : i think he means he can easily measure a heavier weight bow...or he has one on hand that the lad can use , but wants to know if it will do the trick.


if youre making a bow for him , i would work it up to about 45# @ 25" . that way can just use it now and will grow into it.


are you indeed making a new bow or lending one of yours perhaps?

i would get a luggage scale (about 8$ from wally or martK) , and see what kind of weight you are pulling at the drawlength.

shaun does have a good point , in that someone using a 28" bow at 22" is essentially short drawing. doesnt mean its a bad thing , but you will obviously see a loss in performance from the 28" draw...


-hov
Title: Re: Bow design for 22" draw?
Post by: razorsharptokill on January 11, 2011, 04:40:00 PM
The young lady in question is 5' tall. She can easily pull and hold 30lbs at her draw length. I think she will have no trouble building up to 40-45. She has only been shooting for a couple weeks now.

I have a 55 @28 recurve she could try. I could put it on my tiller tree to see what it is at her draw length. I was considering building her a one pc KennyM longbow. I have the material for a 50 @ 28" on hand with 64" ntn. I think that would be a little long for her though. I could go with a thinner stack thickness and shorten ntn down to 60"?
Title: Re: Bow design for 22" draw?
Post by: hova on January 11, 2011, 05:47:00 PM
if i had the lams and things on hand , i would use what i had . i dont do glass yet , but can you lower the poundage by thinning the profile?


-hov
Title: Re: Bow design for 22" draw?
Post by: razorsharptokill on January 11, 2011, 05:52:00 PM
I believe it is best to reduce stack thickness and shoot for a lower target weight. It would be a more predictable outcome I believe.
Title: Re: Bow design for 22" draw?
Post by: hova on January 11, 2011, 06:14:00 PM
understandable. im sure it is a much more reliable solution.

-hov
Title: Re: Bow design for 22" draw?
Post by: kennym on January 12, 2011, 07:16:00 PM
Jim, I redesigned the 62/64" down to a 58/60 for my bros 27" draw to get a little more out of it at shorter draws. It is a whole nother critter. Bro says he can tell the diff from the 64" and it will still draw about 29" on 58" model.

If you cut the 62/64 down to 60 or 58,you lose some reflex(and performance)
Title: Re: Bow design for 22" draw?
Post by: Bradford on January 12, 2011, 07:53:00 PM
I just built 5 54" recurve bows for my kids.  They all turned out great.  They all shoot around 30# at 28".  That is all I was going for.

So.. according to a book I have.. they say 2# for every inch.  That being said, then 52# at 28" should hit 40# at 22"..

I would build her a 54 to 56" recurve glass bow.  You get the power with the smaller bow.  Shoot for 54# at 28".. if it is to much, then just narrow up the limbs some.

If you got the know how, you might want to build a take down.. that way you can just swap out limbs as she gets better.  Just an idea.

Just from building bows, that is my 2 cents.. hope it helps.
Title: Re: Bow design for 22" draw?
Post by: razorsharptokill on January 15, 2011, 07:44:00 PM
Yeah I have take down limb forms for longbow and recurve. Thought about that. Thanks guys.
Title: Re: Bow design for 22" draw?
Post by: razorsharptokill on January 18, 2011, 05:03:00 PM
Here's what I got back from Elmont Bingham:
Hi Jim,



Thanks for your e-mail.  I would suggest:



 .260" using a 15" riser.   Move the press pin 3 inches down the press from the 68" position and shorten the limb template 3 inches at the butt end.  This should give a 60" using a 15" riser.



Sincerely,

Elmont