Primitive Archer

Main Discussion Area => HowTo's and Build-a-longs => Topic started by: Radon on March 28, 2009, 06:41:14 am

Title: Backing a wide limb with narrow boo?
Post by: Radon on March 28, 2009, 06:41:14 am

Hi all

I have a question on bamboo backing:
I want to build a "Holmegaard style" bow, juniper with a boo backing and a pressure resistant facing at the bending section.
Now the only bamboo I have available is about 1 3/4" wide.
The limbs should be at least 2" at the widest point. Any suggestions how to do it?

a) Just glue the boo on the wider wood and leave the outer parts of the limbs unbacked ( -'==='- )
b) Two strips of bamboo ( '=='==' )
c) Three Strips ( '='=='=' )
d) split the bamboo in the middle, bend it wider and fill the gap with a alternate backing (sinew?) ( '=='-'==' )
e) leave it altogather because all the above ideas are crap
f) a better suggestion

Thanks a lot
Radon

Title: Re: Backing a wide limb with narrow boo?
Post by: Pat B on March 28, 2009, 11:16:56 am

You can easily make a trapezoidal cross section with the narrower boo back and wider belly. For Juniper this would probably be the preferable method anyway as Juniper is weaker in compression. I only hope the boo isn't too strong for the Juniper belly. How long will your bow be?

Title: Re: Backing a wide limb with narrow boo?
Post by: Radon on March 28, 2009, 12:31:13 pm

Actually, this bow will be purely experimental.
Bow length should be something around 62", 50+x#@28"
max. 1/2 of the limb bending.
Of course the Juniper won't take that. Therefore the bending parts will receive buffalo horn as facing.

Radon

Title: Re: Backing a wide limb with narrow boo?
Post by: matte on April 16, 2009, 12:06:57 pm

the pearson bow company use to back some of their bows with two strips of bamboo side by side length ways.This was during the late forties early fifties.

Title: Re: Backing a wide limb with narrow boo?
Post by: bobnewboy on April 20, 2009, 09:24:01 am

I think that Pat is right about 'trapping' the back.  If you keep the same dimensions as you've written you'll only have .25" of belly material each side of the boo in any case.  Using buff horn as a belly facing will be really interesting, and I'll be following this one with great interest (normally I'm a bit of a lurker in any case  8) ).  If it all comes together well I think that the bow will be a real flyer.

//Bob

Title: Re: Backing a wide limb with narrow boo?
Post by: Talonzz on May 07, 2009, 01:31:22 pm

In the first chapter of TBB2 around page 40 maybe... They talk about backing a bow with multiple strips of bamboo side by side...  Made out of window blinds no less.