Primitive Archer
Main Discussion Area => Bows => Topic started by: Blaflair2 on December 16, 2013, 10:53:10 am
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How much sinew do I need to back a 52" bow? I'm talking deer leg sinew. I have 4 so far
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It will take more than that. If you can't get any more shoot me a PM. I have some I would trade.
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I have heard it takes 16 legs
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About 10-12 decent length back strap sinews will give you a solid 3 courses.
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A lot depends on your ability to shred the sinew and what your ratio of waste is per tendon.
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I don't have enough. I'm working on getting more. And I don't have squat to trade ATM. Thanks for the offer.
I've never done it so ill probly say my ratio sux
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You'll want more on hand than you'll actually need just incase.
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Are you in the lower 48? If so I'll send you some pieces.
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Yeah I'm in NY. A lot of my buddies didn't get many deer this year
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Send me a PM with your address. They might not be the longest pieces you've ever seen but they will definitely work.
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I have done 4 courses with as little as 8 tendons with a bit left over. It's all in how you apply it
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Marc,
When you say courses are you describing layers of thickness?? Please help me with the terminology. and I guess you apply it very thin also.
DBar
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When we say courses it means layers. Most people apply sinew over the entire limb but I do not. Many years ago I did some thinking on the subject matter and I deduced that it was not necessary to apply sinew that way. What I started doing was to apply the sinew to maximize it's use plus keep the added mass as low as possible. I figured that a limb does most of its tension work down the center where you have a crown and that the outer parts of a bows limbs do very little work. I knew that sinew is more elastic than wood so it could stand to have a high crown. What I therefore did was to apply no more than 1 course along the edge and the outer limbs. Then moving were 2 courses progressing to 4 courses down the center of the limb. This produced a higher crown, almost like a cable of sinew down the center of the limb. All of the bows I sinew backed were short, highly reflexed static recurves and they all shot into the 180 fps with 10 GPP arrows using dacron strings. I'm sure that with FF strings and a bit of tweaking of the design it would have been easy to shoot 190+. Jeez, just talking about it makes me want to make one :)
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For the last several years I've been doing it the same as Marc, lay down a ribbon of sinew down the center of the limb so that it creates a crown and focuses all of the tension on the sinew rather than the wood. Usually this ribbon of sinew is only 1/2 inch wide or so. If I'm worried that a splinter might raise as the wood bends, I'll put a layer of the thinnest rawhide I can get over the whole bow's back once the sinew's cured for a few months. I've found this approach offers me the best trade-off between the benefits of sinew (higher elasticity, holds down splinters) and the drawbacks (tedious work involved in shredding and applying it as a backing, higher weight-to-strength ratio).
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Thanks Marc and Eric,
I have been researching this a lot and have come to the conclusion that more layers /courses or thicker sinew in the middle of the bow is best. Thanks to Osage Outlaw I have enough sinew to build my first sinew back bow this winter. I'm going to start this weekend.
Thanks again for the info.
DBar