Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on May 14, 2017, 08:55:10 pm
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When you are tillering a short bow how do you know when to stop pulling? I'm going to rule out, "Pull til it breaks and then back up one step."
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When it stacks badly or string angle is too great.
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Drawing more than 1/2 the overall length on a selfbow can be a disaster.
"A bow fully drawn is 9/10 broken".
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What JonW said, as well as whatever draw length I planned on. Ill plan a desired draw length and continue working the stave until it draws that length that I planned, unless it doesn't make it. Of course you have to be reasonable when deciding you draw length and bow length, but I have found the general rule of draw length times 2 to be a little overly cautious.
Eric
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Mass principle from tbb may be better for estimating if it's being strained too much.. But the *2 rule seems great for straight bendy bows
I don't see why you can't have a 50" wood/something (sinew? grass? linen?) composite bow pull 32", it's just gonna stack and have an acute string angle unless it's some kind of crazy design. should probably be wide & made of a dense wood.
Doesn't seem like an easy task to do well though. I mean just taking a 50" hickory stick, cable backing, deflexing it and it'll probably stand 32". haha. but it probably won't perform very well..? It'd probably be a sluggish piece of trash. I should try it and see. Ugh, without recurves and no reflex, it would stack horribly...
I think it'd be a lot more practical for most people, hypothetically, to have something like a 53" bow with 28" draw. I don't see why it wouldn't work well with, say, Osage with short hooks and wide limbs? If I were to try it, I'd try to figure out a target mass from the mass principle, and try to do no set tillering.
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its just like a longer bow,, usually less than half the bows length,, is a good starting point,,
if the bow starts to take set,, stop there,, etc etc etc,,
the wood will usually tell you ,, by taking set that you are pushing the limit,, (--)
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Ok. I take half the bow length and take off 5 inches. Works for me.
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Draw length multiplied by two is going to be the best starting point on an all-wood "short" bow design. I've shot enough over-worked, spongy pieces of junk to know over-worked bows suck, I don't care what draw length they take without breaking as that doesn't mean or measure anything substantial. And they will break down much, much faster the more they are shot. History continues to tell us what works(ed) best, it never lies.
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Draw length multiplied by two is going to be the best starting point on an all-wood "short" bow design. I've shot enough over-worked, spongy pieces of junk to know over-worked bows suck, I don't care what draw length they take without breaking as that doesn't mean or measure anything substantial. And they will break down much, much faster the more they are shot. History continues to tell us what works(ed) best, it never lies.
x2
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I make them heavy, when I get to around 25" I Know to release because it's about to pull from my fingers. This is a 52" osage bendy handle selfbow that pulls 65#@25".
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One exception is Dave Mead's design (50", 28" draw), though the bending limbs are made of grass. Mine doesn't seem overworked
Don't remember how long for the draw length Marc's deflex shorties were, from the PA article...