Primitive Archer
Main Discussion Area => Bows => Topic started by: Hrothgar on October 04, 2012, 08:57:20 pm
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I have this 64" hackberry stave thats giving me problems-- its floor tillered, 2 1/4" wide at the fades. It has a twist at one end, but also a curve about 2/3 of the way up one. I can probably sand or scrape that small pin knot without any ill effects, it tends to accentuate the curve in the photo. I was wondering if it would be best to leave the twist or try to heat and 'untwist' it some--I would guess it to be about 30-35 degrees.
Thanks, Eric
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Here are a couple more pics that show the twist better. I guess I would need to start at about the handle area since it seems to begin there.
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If it were me, I would heat the twist out of it. Some guys don't worry about it, but I like to get the tips straight with the handle. Getting the twist out is fairly easy with a heat gun and some weight on the tips.
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I for one would leave the prop twist.
Do what you need to so that the string tracks through the handle though.
I like use what nature gave me.
I'm gonna be building another anyway, so If i dont like something then I will try to avoid it next time around.
I'm always trying to learn.
To each his/her (do you know any female bowyers?) own.
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I wouldn't bother with it. Most of the bows I have made have prop twist to some degree, including the last Hackberry bow I made. It twisted 15 degrees or so on one limb and kept going for another 15 degrees on the other limb. When strung, you don't see it, and it has no effect as far as I can see on performance. Heating and bending wood weakens it. You therefore have to have more mass to counter the loss which has a negative effect on cast. Probably a very small effect, but some. Why bother if it's just a cosmetic fix. Just my take. Got a buddy that just won't have prop twist, no way! Offends his sensibilities.
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Not enough twist to worry about. Build the damn bow! ;)
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I only made 1 bow so far but one of my limbs has that same twist. I just went ahead and built it anyway, it works fine lol.
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I agree with the others. Just leave a bit of extra width at the tip of the twisted limb to allow extra sideways adjustment of the nock to help keep that string line true.
Keep and eye on it by looking at it from the side when it's on the tiller as well as straight on.
E.g looking down the length of the bow when its at half draw will help you see if its pulling back ok or trying to bend sideways. Prob be ok on a wide flat bow.
ELB can really try to go sideways on you if you don't watch out.
Del
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Like has been said to each their own,but I'm with Osage O ,to easy to straighten it out with dry heat,so I would take the propeller out. :) I see no reason to leave
it when it is so easy to remove. :) Now on the other hand if you don't have the stuff to do that and don't want to invest in a heat gun and a few clamps it will be fine,just may have to tweak the nocks so the string lays correct and don't pop off. :)
Pappy
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I have had the same problem recently on a yew bow. I was adding slight re-curves and just carried the heat further down the limb clamping and adding shims as I went. This pulled or flattened out the twist along the way.
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I say straighten it out... hackberry take to heat like a duck to water :)
Clamp wars with some propeller twist and Vinemaple ????
(http://i28.photobucket.com/albums/c210/coaster500/Clampwar.jpg)
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In my opinion hackberry should be heat treated. And since it needs to be tempered,most of that twist will come out over a form while its being heat treated. Kill two birds with one stone.
*edit*...actually you can kill mutliple birds with one stone this way..you can fix twist,side profile issues,induce reflex,string tracking etc...all while tempering it over a form. I've taken nasty 90 degre plus twisted staves with ups n downs,and string tracking off by 2"+,and fixed it all over a form in one tempering session and inducing some reflex n shape.
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Great pic Coaster looks like one of those Escher drawings :D
Del
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When I saw that mess I couldn't help myself... had to get the camera ;)
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There is obviously no "right" answer for this bow because it's not enough twist to really be messy to work with and the wood does take heat like a duck to water.
If you do decide to take out the twist, you can take a few degrees with every 6 inches of limb and never really have to strain hard to get it!
Best of luck, and as always, post pics.
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I am one that will try to heat and untwist/uncurve. I'm not always 100% successful, but I try to get as much as I can. What is important is that the string line up in the center of the bow where it is being drawn.