Primitive Archer
Main Discussion Area => Bows => Topic started by: petew on July 10, 2010, 05:26:56 pm
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I have a nice looking Osage stave ready for a bow build , it is 66" long, but the kast 4or 5" has a severe twist, leaving a good 60" stave without any twist to try to correct. I only draw 27" and want to have a finished target weight of 48 to 52# at 27" with a cut in shelf, and non bend handle. Is this a realistic posibility?.As it lays now the bow should have a natural Deflex in the handle with some reflex in 1 limb, and the other limb will need to be bent to have the same reflex.The bending to match the limbs is not a concern, I have learned how on other staves, with good results.
So the question to the masters is, ... what would be a good layout dimention, for the width of the limbs to make a 60" osage deflex reflex bow that will draw 27/28".
Is a Holmgard possible, feasable with 1/34 to 2" wide inner limbs?
Second choice ,same width straight limb tapering for the last third of the limb?
Third choice piramid limb same width
All would be with a 4" handle and 2" fades.
Any guidance is greatly apreciated, I am new to this and Osage is very dificult to get in Alberta.
There is always risk , but I want to avoid dumb mistakes.
Pete
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I think it is doable. Just take your time with the tiller.
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When you say "severe twist" how much do you mean? Put a straight edge across the back of the bow at the handle and another at the end of the limb with the twist and compare. 30 degrees? 45? 90?
You may want to take out as much twist as you can in the affected area, and then take out some more in the limb closer to mid limb to get it close to square. I've left some bows with as much as 45 degrees natural twist in the limb without much problem, but then I have been pretty lucky, too.
Good Luck.
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The twist is close to 45 Deg over 5"on the stave.All the bows I have done so far have been on the long side, so I thought that this one was a good candidate to cut the twist off and make a shorter length bow that might be easier to hunt with.
Pete
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A good rule of thumb is draw length times 2 plus handle length plus 10 percent. Tiller it slow and you'll be fine.
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and,,,then again all wood is different, I wouldn't hesitate making one 60".
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I'd go with a bend in the handle D bow if it was me, since Osage is hard to get for you. Good luck !
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I think, with enough patience, 60 inches is doable. I would go with 1 1/2" fades instead of 2" to gain some working limb.
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My first foray into Osage is with a 60" stave (restrictions on shipping lengths :( )
I'm going for as much working limb as possible (must measure it some time) with the grip/handle centred and straight, wide limbs to spread out the stress of drawing as much as possible - aiming for 50-55# at about a 27" draw. To my mind, altering the profile with deflex or reflex effectively shortens the finished brace height and makes it more difficult in reaching a higher draw weight at a decent draw length. Anyone any thoughts on that?
I'm getting close to putting a string on my stave for tillering after working on it once or twice a week since I received it in the post on March 23rd :D how's that for taking it slowly?? ;D
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hatch i got ya beat
ive had the same stave for almost 3 yrs now,and yes i have been working on it during them 3 yrs
its finally to floor tiller
i think about another 2yrs and it should be finished ;D
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I would remove the twist, pretty easy with a heat gun, a pipe wrench and a bucket full of anything heavy, even water.
(http://img.photobucket.com/albums/v181/ekrewson/propellerpost.jpg)
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Take Eric's advice and remove the twist. If you plan on working with Osage a lot you will need these type skills down the road, there isn't much risk in trying to straighten it. If successful, this will allow for any of the above designs with plenty of wiggle room. Good luck on your bow, Osage I find always wants to be a bow so its never as bad as it seems. It will work with ya.
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I guess the part I did not emphasize is I want to make a short bow, the twist in this stave just made it a more likely candidate than one of the better, straighter staves.
Pete
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Oh, ok. Then the answer is yes, the wood is perfectly capable of pulling it off, not sure about the rest.
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Yes it should be fine at 60 at that weight and draw, if it is good Osage. I would go with the second choice and go about 1 1/2 should be enough to mid limb then tapper to the tips,at least that's what I would do. :) Good luck and keep us updated.
Pappy
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If it has good rings, you shouldn't have any problem getting what you want from it. It doesn't take much osage to make a bow. Don't think I'd try a Holmegaard, though-i think it's a better design for lighter white woods. I'd do like Pappy said, and maybe flip the last 2"-3" of the tips up a little.
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you could get 27" out of a piece of 56-58" osage being 1.5" wide at the fade. you could even go with a 1.5" long fade. osage is some wonderfull wood. i've made a bow pulling 50#@28" out of a 52" stave, just go slow. you could always heat treat the belly for some extra insurance.
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Thanks for all the great suport and sugestions. I will try to take some photos as I go on this one and post them.
Pete
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I made a handful of bows years back for a kind of challenge, or contest, criteria was 60# @ 28" and no more than 58" ntn.
This was one was spliced billets deflexed with the limbs recurved slightly w/ kerfs. It was not the best of the lot.
(http://home.comcast.net/~dcm4/pwpimages/abc2b.JPG)
This one (the bottom bow) was a simple selfbow. Only pic I have to give you a sense of the width taper.
(http://home.comcast.net/~dcm4/pwpimages/dina1.JPG)
Here's the one cited above (on the left here) at full draw. Beside it a very similar one but with slightly stiffer outer limbs and arrow pass slightly higher.
(http://home.comcast.net/~dcm4/pwpimages/ap.jpg)
None of these were over 1 1/2" wide, with a typical flatbow taper, although the first bow more pyramid-like width taper. They all took about 2" of set, following the string about an 1" depending upon where they started. All seemed to shoot fairly well.
You should be fine if you have decent wood. It ain't for free by any measure, but definately doable if you take your time and mind yer manners.
I'd discourage a cut in rest in favor of one built up from leather, perhaps as much for personal preference as structural strenght. While folks seem to do fine with cut in rests, I fear it introduces a weak point, unnecessarily in my view.