Primitive Archer
Main Discussion Area => Bows => Topic started by: cadet on June 28, 2016, 06:19:49 am
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Got a bit of time and space, so took to the tools again: I've just about finished with a slat of spotted gum ripped from a decking plank. It looks delicate - 76" tip-to-tip, only an inch wide at the handle and 3/4" thick, narrowing and thinning to about 3/8" at the tips - but it's a hard, heavy timber, out to 26" now and pulling well beyond 50lbs, and barely half an inch of set once relaxed. Nearly done; I need to bring the inner limbs around a bit more yet. Anything I've missed?
(http://i606.photobucket.com/albums/tt146/cadet450/July%20spotted%20gum%20unbraced_zpszyxewegj.jpg) (http://s606.photobucket.com/user/cadet450/media/July%20spotted%20gum%20unbraced_zpszyxewegj.jpg.html)
(http://i606.photobucket.com/albums/tt146/cadet450/July%20spotted%20gum%20full%20brace_zps9rpauekm.jpg) (http://s606.photobucket.com/user/cadet450/media/July%20spotted%20gum%20full%20brace_zps9rpauekm.jpg.html)
(http://i606.photobucket.com/albums/tt146/cadet450/July%20spotted%20gun%20near%20full%20drawn_zpsnjn4ydmy.jpg) (http://s606.photobucket.com/user/cadet450/media/July%20spotted%20gun%20near%20full%20drawn_zpsnjn4ydmy.jpg.html)
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The hinges at each tip? ;)
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Yes I think you thinned the outer limbs a wee bit too much
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I would agree. I think you need to remove some wood from handle to just past mid. limbs. Your going to have to give up draw wieght to save this one. If you look at your picture almost all of your bending is happening in last 1/3rd of bow. I'd try tilering it out it might end up light but it's good practice. Avoid areas that are bending get the ones that aren't moving. Good luck
Bjrogg
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Your right limb is also way stiffer but you need to get the inner limbs working more
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At that length you have room to cut 2 - 3 inches off each tip and fix the tiller. Just don't pull it so far until you sort out the outer limbs.
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Very whip ended bow. I'm surprised it has taken so little set. I'm with the other guys. Tillering is simple: take wood away from areas that aren't bending, and leave alone the areas bending enough. Get the inner limbs bending and cut the bow down a few inches.You can still end up with like a 68-70 in bow and still have some decent draw weight. Benefit of making a longer bow.
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Thanks all for the feedback.
I'm not entirely displeased with the shape, but yes, it is whippy, and I do want to get the inner limbs working more, and could shorten it. What little set it's taken is all in the outer limbs. I'm still seeing what spotted gum can do; I suspect - like a lot of our timbers - it's a much harder, heavier timber than north Americans and Europeans are used to playing with.
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I've done a little more work, getting the inner limbs working a touch more.
Could someone explain to me some of the pros and cons of whippy ends? I'm no engineer, but perhaps there's a place where they may be useful? Certain timbers? Designs? Effects we want to achieve on strings and arrows? They can reduce moving mass near the tips after all; and isn't that something we're trying to achieve?
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I like the simplicity
Whippy ends may be faster with lighter arrows, but will be slower with heavier ones. Less stored energy is the downside.
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The bow just isnt working to its potential....theres a lotof limb that could be bending. All that work being done by so little wood will greatly shorten the lifespan of the bow.
I like the idea of shortening the bow a little and retillering.
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At 76" long you may be better off with the tiller you have now. It will be a lot less shocky. If you do decide to drop with I would go for the inner limbs. All those old long target bows had whip tillers.
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I was thinking the same thing Badger.
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I think you two are unto something, but this one might be a bit extreme. I would like to see at least 6-8" per limb more moving with maybe 16" in the middle stiffer. As is, its a bit more than a simple old school whip tiller.
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The left limb looks more whippy and like it has a hinge.. and it also appears to have more set. You don't want a few inches doing most of the work.
I think the right limb looks fine, but maybe there's a hinge near the tip? Correct me if I'm wrong