Primitive Archer
Main Discussion Area => Bows => Topic started by: cool_98_555 on January 08, 2017, 11:12:28 pm
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Hello everyone,
I am tillering a heavy osage bow right now that has a slight twist in one limb but no twist in the other limb. Thickness is even on both sides of both limbs. I tried checking string alignment on the tips and they seem to be going through the center of the handle on the back of the bow. I am very close to bracing it for the first time at around 3" or so, but whenever I try to brace it, the limb that has that slight twist seems to want move in the direction of the twist in that one limb as I am trying to brace it. Any of you have experience with this? I don't really want to actually brace it 3" or so if I am getting this kind of effect. It just doesn't feel right when trying to brace it,...like something is out of adjustment. It's almost like that one limb is trying to "roll over" towards the twist when I try to brace it. Any ideas? Thanks for all your help guys. I appreciate it.
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Check for uneven limb thickness. That will cause the limb to twist more as you put tension on it.
Are you using a bow stringer?
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I'm not using a stringer right now. Limb thickness seems pretty good for the most part. I checked with a caliper to be sure, and there are some areas that are thicker on one side by a very small degree, but the side that is thicker actually is on the "weaker side" of the twist, if that makes sense. This stave is confusing me.
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Any reflex? That can make it try to turn itself inside out sorta.
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Yep there is a little bit of reflex in both limbs, maybe an inch or so.
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I've found a little reflex makes it tough to get a low brace. Maybe floor tiller until you can get full brace.
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And double check the sticky above concerning limb twist. This particular concept really doesn't like to stick in my head, and I have to review it occasionally.
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on the problem child bow,, I tie leather nocks below the cut string nocks,,then I put a long string on the leather nocks,,
then I pull it and string it,, I let it down gently the first time incase my floor tiller was off,, like if one limb seems to bend to much and then even it a bit more and try to string again,,
a fast flight string will stretch less and make it easier to brace the refexed bow the first time,,, be patient and go slow you will get it,, :)
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Have you considered heating out the twist? Osage holds heat manipulation extremely well.
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I am with brad smith, using fast flight string material made it way easier for me to string my heavy draw weight HHB bow. I first used Dacron 50 and simply was unable to string the bow because of the stretch. My bow was also slightly reflexed and it just went flat with the string tight to the belly, when using the Dacron 50 when trying to string it the first time to a low brace height. That in itself won't fix your twist but at least makes it easier to achieve a low brace. Floor tillering it first seems like a good solution to me as well.
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I've had that happen with reflexed staves. Try cutting the nocks in a little deeper opposite from the direction it is going when being strung. File both sides in a little deeper and see if that helps. Jawge
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I have to try using a FF string to get it braced. You're right...every time i try to brace it i can only get it to go tight against the handle but no brace. I might try to heat out the twist too. Like i said i checked wuth a caliper and i have pretty even thickness from side to side. This was a 4-year seasoned stave so I don't want to try to stress ir too much bracing it if it's naturally twisted
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I have tried to clamp two laths sandwiching the limb to untwist. this is if the twist is not because of thickness disparity, if you can see the twist with the unbraced bow..
There is also this http://www.primitivearcher.com/smf/index.php/topic,53195.msg722044.html#msg722044
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I can barely see some twist in one small area on one limb in the unbraced profile. But it is hardly distinguishable, causing me to go back to it study it many times over to figure out where it is twisting and if I can actually get the twist out with heat
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Make sure your floor tiller is good then just shorten the string until you get it braced. An inch or so brace height is enough. Yes B50 stretches but it isn't that big of a deal, it will only stretch so far. Make a stringer and cut some tempory nocks into the back above your normal nocks, you need control for intial bracing and a stringer gives you that (not a modern glass bow stringer!).
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I can barely see some twist in one small area on one limb in the unbraced profile. But it is hardly distinguishable, causing me to go back to it study it many times over to figure out where it is twisting and if I can actually get the twist out with heat
I've had a couple of bows that looked like the string alignment was perfect when they were unbraced. When they were braced the alignment was out. I steam bent the handle to bring them into alignment and they've been fine ever since. The bow just wanted to bend in a different direction than I thought it did. This is one reason for not shaping the handle until you have it braced.
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I just don't like the way it starts to twist in my hand when trying to brace it. Should I just try to get it braced anyway and not worry about how the twist is rolling over the limb when trying to brace it and then just see what happens after brace? This is one of those bows that looks like the twist is so minimal it shouldn't even make as much of a difference as it is right now, but it just feels weird when trying to brace it up, suggesting something is wrong. I've studied this bow from every angle and tried to look at it in different ways but I can't put my finger on why it's deciding to move on me....limbs are even thickness, twist is very very minimal, almost indistinguishable....doesn't make sense to me. Maybe when it's braced it will look different? I don't know...
Thanks for all the advice so far everybody...
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As long as the tiller is good I would brace it and see what it wants :D
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I actually got it braced a couple inches, but the string is off center by about 1/4". I looked down the bow, and the twist is so minimal that it is nothing to worry about. I think I have to heat the limb tip on one limb that isn't straight to get the string aligned first. This bow has been pretty stubborn when I have tried to heat it before, however. Perhaps because it has been seasoned for 4 years....I don't know. Anyway, wish me luck! Excited about this bow.
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If it's only out 1/4" just leave it until further into the tillering. It may move around. If mine are out 1/4" I make the top limb the one that puts the narrow side on the arrow side ;D ;D