Primitive Archer
Main Discussion Area => Bows => Topic started by: driftingrz on August 17, 2012, 11:15:25 pm
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hopefully this is the right place.. i searched and came up empty.. cause virtually every thread has the words twisted or limbs in it haha. or maybe i just dont know what to search for..
anyways.. im in the final tillering of my 1st bow :D.. just a cheapie redoak, linen backed bow.. nothing special. just trying to learn some stuff on a few boards before i tackle a stave..
i finally got the bow braced around 6" today with a much more even tiller than I had.. but now im noticing some twist in the limbs.. its a constant twist from nock to nock..
not a spectacular picture.. but you can see the left side is bending more towards the belly.. and down on the other side the right side is doing the same.. so regardless if im holding the bow the limbs are twisting the same way..
How should i go about fixing this issue.. which side needs wood removal?? or maybe im worrying to much? also.. the string is still dead center of the bow while braced, if that makes any difference..
im still a noob and learning. bout to start TBB v2 so ill take any help i get..
(http://i6.photobucket.com/albums/y224/DriftingRz/2012-08-17_21-21-22_149.jpg)
while ive got you fellas in here. maybe i can get some input on the current tillered state.. its not perfect..
i have my own thoughts about what needs to be done.. but id some expert opinion.. i havent had time to make a real tiller tree yet. just been using a 4x4 post on my deck and some nails to get an idea of the bend.. as it sits its braced at 6" and pulling 40lbs at 24". i havent had pulled it to 28 yet which is my drawlenght
(http://i6.photobucket.com/albums/y224/DriftingRz/2012-08-17_18-54-47_576.jpg)
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If you only notice the twist while the bow is braced it is because of uneven thickness. Check the thickness of both limbs from side to side and you will find one side slightly thicker than the other. Making both sides the same will eliminate the twist.
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well its twisted while unbraced.. because of the set its taken i guess.. but yea its more severe when braced.. i cant tell a difference in thickness.. ive been staring at the limbs all day haha.
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Does the twist straighten out when you draw the limbs some, or does it get worse? Hard to tell from your description, but you said it was twisted when relaxed. If it is propeller twist, and the string lines up down the handle, and it straightens out when drawn, I wouldn't worry about it. I'm looking at six bows leaning against the wall and 4 have some prop twist. Never been an issue. But, as Pat said, check the thickness of each side of the limbs with a set of calipers or a crescent wrench. If the difference in thickness is causing them to twist you gotta fix that before you go much further.
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the twist stays about the same from braced throughout draw.. ive measured limbs and cant find any differences..
ive tried rasping and scraping and just cant seem to make any difference. in "theory" which side should wood be removed from? the side thats twisting towards the belly?
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In theory you sould remove wood from the lower side
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I have never made a board bow before but the principal is the same I guess.
If one side of the limb is thicker it will resist the bend more which puts more strain on the weaker side and so the bow limb leans towards weaker side causing twist. In a stave bow sometimes the twist can just be natural prop twist caused by the way the tree grew. This is often caused by the prevailing wind pushing the tree in one direction as it grows or the tree chasing the sun. If your limbs are equal width just ignore and carry on. If one side is thicker remove wood from the thicker side of the limb. Uneven thickness in limbs can cause weakspots and crystals.
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I have just finished a red oak board bow myself and have the same problem
So as we look at the picture on top which side would you remove wood from in the event that both sides seem to be the same thickness? The right side of the pic or the left side of the pic?
Also for reasons of consistency what type of twist is this called?
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Pats advice is dead on for a board. Twist hurts nothing as long as the string bisects the handle and stays on the bow. I must admit it looks fine by be. A good way to remember which side to remove wood from is easy, the strong side stands tall while the weaker sides bow's. If your holding the bow belly towards you and say the upper limb curls to the right, that means the left side of that limb is standing tall. Remove wood from that side.
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I would round the corners, especially on the back, and narrow the tips first.
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That really isn't enough twist to worry about. Wood bows can handle some twist and this in minimal. Also like scp said, round the corners(edgesof the limbs), narrow the tips and get her shooting.
You can "perfect" yourself into a very low weight bow real easy. Get this bow shooting and apply what you learn from this one on the next one.
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And remember.....its wood. Not glass or carbon.
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Thanks for the help guys. I actually did hace the tips narrowed but my nocks we're so hideous i chopped an inch of each limb and redid them
Appreciate it