Limb Twist Removal?

[Prarie Bowyer]

Wait.  I start thinking myself in circles.  Working on an ELB and one limb is litteraly twisting as it draws.  Do I take wood off the low side or the high side?

Logic dictates that the high side is high because it's more rigid so the low side is gettign torqued becasue it's more flexible.  Working in small amounts and I don't see quantifiable changes.

I can also reason that the force is pulling on the hard part and the soft part is able to float up.  So which is it? 

There was just  a thread here I read where someone did an experiment and discussed it.  Where was that?

[Cameroo]

This is probably what you're looking for:

http://www.primitivearcher.com/smf/index.php/topic,27206.0.html

[Prarie Bowyer]

Thanks

[JW_Halverson]

Pretty counterintuitive until you read 4est Trekker's explanation.  In the years to come there will be plenty of enpty spots in people's "Corner Of Shame" due to his posting!

[Del the cat]

With an ELB it is so long and narrow any slight lateral bend can complicate the issue, making the whole thing feel like it is suddely going to go completely sideways on you.
If you are worried you are taking too much of the profile, maybe consider putting in some lateral bend to sort the prob.
Here's http://bowyersdiary.blogspot.com/2011/03/twisting-bow.html a link to a bow in my bowyers diary where I had similar worries, maybe it will help. The next few posts after the linked one may be useful.
Del

[Prarie Bowyer]

Thanks Del,

It turns out the boward I cut the wood from had some kind of twist going on .  It became prominant int he other side also after I cut the stave free.  The limb was literaly twisting.  It didn't matter anyway because the OTHER limb broke on the tree.  I've cut the other stave and am traying to do a semi ELB looking thing with the Bamboo/Lyptus sandwich.  Liptus core was WAY too thick So I split it apart and took the jointers plane to it.  Waiting on glue to reassemble.

[Prarie Bowyer]

I got to thinking and I realized that ALL attempted bows had that sort of twist going on.  I think it was a grain thing.  The limb literaly twisted as it was drawn.  It seemed to stay in line.

Since I shaved the Lyptus down alot I'm considering flipping the tips.  My thinking is to put a thin partial lamination of hickory in the tips about 9"-10" long and then flip them.  The hickory and bamboo have straight grain so the Lyptus should be trapped and unable to twist.  I hope that works.  I guess I need to heat the belly also.  I promis I'll get pics up.

I'm thinking of doing something "Avatar" inspired if the bow actualy works.  I have some lapis lazuli I'd like to set in the arrow pass.  I'll give it a blue and black string and make arrows fletched in red and blue.  I'd love to find some Mackaw feathers.  Maybe a blue and red handle wrap.

[Matt S.]

Prarie Bowyer, not that this helps but the past two bows I've been working on have ended up with twisting limbs. Removing wood from the high side (as wonderfully illustrated in the linked topic above) helped, but one bow still twists. Its high side is now thinner than the low side, so I just think some wood is prone to twisting depending on how it grew (this bow is from a maple board). As long as you can get full draw and don't feel the bow torquing in your hands I don't think the twist will negatively impact the bow's performance, it just looks a little ugly, imho.

Bubby made an Avatar inspired bow about half a year ago. If I had some more time I'd search and post a link to that topic. It turned out really nice and would be worth looking at for your project. Best of luck!