hollow limb questions

[sound maker]

  I have some questions and some might be simple but I just want to be sure I get this right.
 and they are..
Can the hollow limb design be used on a board bow or no?
    Would birch be OK with this design with a stave that's about 6'??
           Can I do the hollowing part by start it with a v bit cut into the wood and then curve it??
                    I'm kind of limited on tools so I'm not really positive on a good method with what I have which is basic so any help with trying to do it would be nice.

thanks for any advice you can give for this.

[Bryce]

I would hit up simpson. He's been turning out some nice hollow limbed bows.
I'm sure it would be possible to do with a board as long as there was enough wood to work. Basically your just following the natural curve of the growth rings on the back and front.
A curved cabinet scraper would probably be nifty.

Birch seems to be weak in tension, and can fret pretty easily. So I'm not sure that it could handle it, but I would love for you to prove me wrong
http://www.primitivearcher.com/smf/index.php/topic,2544.0.html

-Pinecone

[bubby]

Birch seems to be weak in tension, and can fret pretty easily. So I'm not sure that it could handle it, but I would love for you to prove me wrong
http://www.primitivearcher.com/smf/index.php/topic,2544.0.html

-Pinecone
birch seems good in tension, i built a black walnut with birch back and a birch self bow just recentlly and i'm pretty impressed with it, but maybe i'm just easilly impressed , Bub

[Bryce]

Well shoot, I must have had some bad birch or something

Looks like I need to give birch another few tries . Thanks for the correction bub.

[sharpend60]

I thought birch was a decent tension wood.
But it may fret easily, meaning it don't compress so well.
I would think you need good compression wood for a hollow design (juniper). But I dont know for sure... Hollowing seems to be like reverse trapping kinnda, sorta... Or even like a the reverse of a rounded belly...

[SA]

seems like druid posted one also a while back it was a stave bow too if i remember correctly..maybe they will chime in, kinda have me wanting to try one of those. i say just do it and see what happens

[lostarrow]

Lots of different types of birch . Sounds like you're talking White vs.Yellow.White (Paper) is like Poplar while Yellow is like Hard Maple.

[Jim Davis]

The fellow over on the LW who patented a laminated fiberglass hollow limb design didn't end up with any improvement over standard limbs, if my impression from posts is correct.

I have thought about wood limbs that follow the growth ring's curve. The compression would be most intense at the sides of the belly, because the effective thickness of the limb would be from the crown of the back to the edges of the belly, like this: )). The only way to have the full width of the belly doing equal work is to have the full width an equal distance  from the plane of the highest part of the back--a flat belly.

Jim