I have been working on getting a hickory billet down to a stave configuration. It had some twist and a slight bend. I was able to get a straight stave but it has about 35 degrees of twist from tip to tip. The handle area is fairly straight. Since this is my first attempt at building a bow from a billet should I expect to get something usable out of this or should I plan to removed the twist before I begin tillering? I am not really concerned about the final draw weight as I am scoring this one as a learning experience. :confused:
With osage propeller is the easiest problem to fix, don't think I have corrected a similar hickory stave but suspect if done right it won't be too hard.
Cut you limbs to about 3/4" thick, clamp the handle in a vise, put a pip wrench on the limb, hang a 5 gallon bucket from the pipe wrench and add weight to the bucket while heating the limb with a heat gun until the propeller twists out. Let the limb cool and you are good to go.
Always remove propeller with the limb's belly up in your vise, that way you don't deflex the limb and may add a little reflex.
If you have already shaped the limb to it's final profile, put the tip in the vise padded with leather then put the pipe wrench on the handle and remove the twist.
(http://img.photobucket.com/albums/v181/ekrewson/propellerpost.jpg)
I have a post on the end of my work bench to support the limb while I remove propeller. The vise alone won't hold the limb up while you add 50 or more pounds to the bucket.
You can use a caul as well, of any shape. Doesn't have to be curved. A straight 2 x 4 or whatever, 36" long or longer, would do. Just need something to hold a clamp. Heat the wood with a heat gun, paint stripper. If you ain't got one of them, a 1500 watt hair dryer would probably work but it would take a while longer. And some risk of burning it out. Probably cheaper to go buy a heat gun for $20, versus having yer wife mad at you, and then have her spend $25 on a new hair dryer. LOL
You can heat the wood with anything, your kitchen stove. But you have to get it into it's new shape fast, within 10 or 15 seconds of removing from heat.
This is osage but hickory will work as well or better. Use a good long heat soak, 5 minutes. You want it heated through, not just on the outside. Also be sure you wood is fairly dry, seasoned for tillering. Wet wood will check if you use dry heat, but can be steamed.
(http://home.comcast.net/~dcm4/db2.JPG)
Thanks for posting that again, Eric, as I have to do the same thing soon with a roughed out osage bow and needed the refresher.
Eric and Dave thanks for the advise. I will have to get that heat gun because the blow dryer my wife will let me next to is not long for this world.
All kidding aside I think this stave will come out pretty nice when it gets straightened out. Thanks again!!
One other thing, when you limb starts to untwist as you heat it, push down on the pipe wrench handle and help the limb untwist a little more. The weight in the bucket will keep the limb from going back.
Eric, do you do this after floor tillering? I have a ash stave with a twist in it.
The limbs are thin enough after floor tillering that you don't need the bucket full of weight and light hand pressure is enough to untwist a limb.
Another thing I have found is a slight twist will pull out of a limb after you finish a bow and shoot it a while.
Thanx Eric. I'll take a pic of the twist and send it to you. This way You can tell me the best way to do it...If that's ok.