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Author Topic: why is my bow twisting??? (fixed)  (Read 5718 times)

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Offline Zion

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why is my bow twisting??? (fixed)
« on: April 03, 2013, 01:50:41 pm »
So lately i've been making a heavy Ocean Spray bow in the warbow design. It came from the straightest piece of wood i've ever seen, but every time I string it or even bend it the whole thing becomes so side warped it's like a crescent. I would think this would be caused by uneven crown but it's quite even. What is going on???
« Last Edit: April 04, 2013, 04:26:51 pm by Zion »
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Offline Carson (CMB)

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Re: why is my bow twisting???
« Reply #1 on: April 03, 2013, 02:06:49 pm »
If your crown is even then maybe the belly is not.  Is the pith still contained within the limbs?  How long seasoned is the wood? 
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Offline PEARL DRUMS

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Re: why is my bow twisting???
« Reply #2 on: April 03, 2013, 02:22:27 pm »
Using green wood will do that to. Some of your bows that are only 2-3 weeks off the stump can really change as they properly dry.
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Offline Zion

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Re: why is my bow twisting???
« Reply #3 on: April 03, 2013, 02:27:25 pm »
I meant the crown on both sides. ( the only crown i can really change is the belly crown.) The pith can be seen at the tips only, and i got rid of it there. Heat treated very lightly several times. Seasoned for close to a year now because i harvested the sticks last spring/early summer. It has no real set right now. I'll put some pics of the stave and bow. In the first pic it is the one on the far right.
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Offline PEARL DRUMS

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Re: why is my bow twisting???
« Reply #4 on: April 03, 2013, 02:48:51 pm »
See how your pith runs from the side to the center?
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Offline bow101

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Re: why is my bow twisting???
« Reply #5 on: April 03, 2013, 02:50:26 pm »
 :(  thats to bad Zee,  I would just maybe use it as firewood and try 'nother piece.   I have run into that problem lots with milled (kiln dried) pieces never mind staves, saplings and such.
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Offline Zion

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Re: why is my bow twisting???
« Reply #6 on: April 03, 2013, 10:13:00 pm »
So Pearly your saying that the grain of the wood is directed wrong so that's why it's warping?

I won't use it as firewood, it's too good for that. Since it's my first real longbow i can do lots of tests and strength training. My 440 lb. spring scale should show up in a couple  of days so i can finally weigh this thing. I think OS would be an amazing wood for warbows tho...
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Offline Josh B

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Re: why is my bow twisting???
« Reply #7 on: April 03, 2013, 11:06:03 pm »
It's hard to tell for sure by your pics on my little phone screen, but it looks as though the outer 6" to 8" of your limbs are thicker than they are wide.  Sort of like Molly levers.  If that's the case, it will be prone to bending sideways if not perfectly aligned.  Especially if there is any reflex.  Just a tiny bit of sideways bend at the tips will definitely cause a twist.  Josh
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Offline Zion

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Re: why is my bow twisting???
« Reply #8 on: April 03, 2013, 11:10:34 pm »
They are thicker than wide. So does that mean i can't have as narrow tips as usual on these bows? The thing is this bow was completely strait but when i try to bend it the bow warps, it's never happened to me before.
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Offline twisted hickory

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Re: why is my bow twisting???
« Reply #9 on: April 03, 2013, 11:21:51 pm »
Never worked on that kind of wood but I had a hickory bow do that. Two heat treats later , a bit of twisting and now it's straight. Will know by the end of summer if she will hold up.
Greg
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Offline Josh B

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Re: why is my bow twisting???
« Reply #10 on: April 03, 2013, 11:25:48 pm »
It doesn't necessarily mean that you can't make your tips that way.  But everything will have to be near perfect for it to draw straight.  On pyramids and flat bows, you have the width of the limbs to help stabilize lever type tips so you can get away with a lot more.  That's not the case with this type of bow, as its narrow profile doesn't provide the forgiving stability.  The wood is always going to try to take the path of least resistance when strained, so its better to keep the outer limbs on these fairly even in width and thickness.  Josh
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Offline Zion

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Re: why is my bow twisting???
« Reply #11 on: April 04, 2013, 12:28:18 am »
Ok gotcha. I think it is also sketchy because the cross section of the bow is pretty much a circle, and the profile is completely straight.... so pretty much it's just a staff. I don't think the wood really knows where to bend. Since i don't harvest large enough logs not to have crown, i think with my next one i'll make the belly flat but still make it with mostly warbow proportions. It won't be traditional but at least it'll work lol. Well now i will be able to do some tests on it tho!  >:D
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Offline vinemaplebows

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Re: why is my bow twisting???
« Reply #12 on: April 04, 2013, 12:31:50 am »
It twisted around while it grew.
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Offline Zion

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Re: why is my bow twisting???
« Reply #13 on: April 04, 2013, 12:41:45 am »
The grain is straight, the bow is straight, only when i try to bend it does the bow warp. Like when you are trying to brace the tension side of a maple limb. What i might do is make the belly oval on this one, (pretty much flat with rounded corners,) pike it to keep the weight and see if it shoots good. If not, it's overdrawing time  >:D
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Offline Carson (CMB)

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Re: why is my bow twisting???
« Reply #14 on: April 04, 2013, 12:42:41 am »
Great advice here.  That is a sweet piece of OS.  I know you wont give up on it.  In the one pic, the leverish tips look thicker than they need to be.   I bet if you take the outer third down a bit it wont fight the string so much.  also, if you toasted the belly of those half lever outer thirds, but not the sides, then you make the problem worse.  Take the thickness down and heat treat the side of the levers as much as the belly, and might not twist on you so much.  Like Gun Doc said, it takes the path of least resistance. 
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"The bow is the old first lyre,
the mono chord, the initial rune of fine art
The humanities grew out from archery as a flower from a seed
No sooner did the soft, sweet note of the bow-string charm the ear of genius than music was born, and from music came poetry and painting and..." Maurice Thompso
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