Primitive Archer
Main Discussion Area => Bows => Topic started by: possum on April 06, 2008, 02:36:18 pm
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Wow, I guess that title sounds more like a personal problem, huh? :-[ Anyway, I built a a 51.5" sinewed back osage bow. It's from a stave I piggybacked. This is the back split. Slightly propellared (sp) and 1.5" wide for about 15" on each limb with 2" fades @4" handle, glued on handle. I tillered it to about 45#@24ish" when the sinewed cured for about a month. Well, I set it aside after deer season and a few days ago I put it in my heat box and yesterday it drew 60@24ish. Well, tiller ain't great now. Where can I get a picture of a good short bow tiller? I know it's short but I'm sure it has a little different arc, or then again I could be off as usual. Thanks,
possum
ps I'm working on a few pics now (or when I log off anyway ;))
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The humidity was probably considerably higher when you were shooting it before. The heat box will also drive out moisture. I would leave it alone and let it stabilize to the RH of your area. If you tiller it down to 45# then the sinew soaks up a little moisture you could wind up with a 25# bow. I'm sure Pat will weigh in and tell you about "elkie" and how much weight it gained by moving from South Carolina to Colorado. Justin
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(http://geocities.com/sp06di/51sinew1.JPG)
This is at 5.75" brace now. I don't have any pics from before.
(http://geocities.com/sp06di/51sinew2.JPG)
This is at about 18". I meant to have it at 19 but I guess I let up a bit while snapping the picture. :-[
It is showing 45@19.
Where is my trouble?
possum
I just saw the post from Justin. How long should I let it sit?
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Possum, You have a little hoop-tee-do about 8" out from the handle on the right limb. Just past that looks a bit stiff. The left limb seems to be bending nicely.
When I built Elkie(60"t/t, sinew backed osage with a similar profile as yours) she came out at 56#@26" with a month drying time after each of 3 courses of sinew. A month later she was at 45#@26" due to humidity. I sent it out to Colorado for a hunt and when I got there she was back up to 55#@26" and a month after I left her in Colorado she was pulling about 65#@26". Humidity has a big effect on sinew backed bows. Maybe thats why the S.E Native Americans didn't use sinew as a bow backing or use short bows. ;D Pat
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I think you should get that near handle wood bending more. In a short bow getting all of the limb to bend is important. Jawge
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I agree with Jawge, but you need to be carefull you are not far from hingeing it. Especially on the right limb just back from the #8 on the wall, towards the handle.
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I think the hoop-tee-do is a knot. I never flattened the knots or removed the extra wood when I sinewed it. I probably should have and it would have made tillering it easier. I'm not sure it is close to hinging I just think it is wider, making it look look like it bends quickly there. Nevertheless, I will look at it more closely when I string it up again. I'm gonna give it a bit to reacclimate to my humidity here as Justin suggested. I will post more pics later, gotta get the kids to school. :)
possum
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Well, I figured I'd post a few better shots of the bow.
(http://www.geocities.com/sp06di/51sinew3.JPG)
This is a side view of the upper limb that had a "hinge"
(http://www.geocities.com/sp06di/51sinew4.JPG)
here is a view of same area but from the belly.
Now, as I see it, the extra wood for the underlying knot made it look like it bends very quickly in this area. It may very well still hinge there... I'm not that good at seeing these things. :-\ So, armed with this new info, please look again and see if you still see the hinge. If you still see it I will gladly rectify it. I will still try to get that near handle wood bending more. thank you,
possum
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I agree with PatB looks a bit stiff on the right limb and near handle wood might need to bend a bit more , but otherwise looks like a nice bow you have coming along there (love the knots )
Chris