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Ash bow from spliced stave: Thoughts on design?
willie:
--- Quote from: MattCav on August 30, 2022, 05:55:25 pm ---
Well, considering those limits, I'll try for something more conservative to start. I'm thinking for this first bow I'll try for 66" long, with a 12" handle section, 1-3/4" at the fades, tapering to 5/8". Seems like that should give plenty of room for a straightforward tiller, but of course, we'll see.
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for a first bow with 12" dedicated to the handle section, I would consider the shortening operation (from 77 to 66) be done further down the road as you see how the tillering goes. In fact, leaving the stave full width until you get it closer to final thickness and start tillering might make thickness reduction easier, depending on how you choose to reduce. band saw? rasp?
MattCav:
--- Quote from: Hilongbow on August 30, 2022, 08:45:16 pm ---Aloha Matt,
I made my first ash selfbow a couple years ago and posted it here http://www.primitivearcher.com/smf/index.php?topic=67374.0
Sorry, its a long read, but if you skip down to the bottom you can see my final specs. I think you are in a great position to get better results than I got. However, I think that the front profile looks really nice, and it shoots sweetly and accurately. I don't think white ash is the best wood for bows, but it holds a special place in my heart.
If I were to do it again, I would definitely have left it a tad wider and several inches longer (I had to shorten it due to knots). During shoot-in, hundreds (if not thousands) of chrysals showed up, but I've taken hundreds of shots and the specs/profile haven't changed. I think the extra length and width would have prevented them.
I'm looking forward to seeing your finished product!
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Took a look - quite a journey! I think these billets are probably a little less intense than what you you were working with! Still, so encouraging to see what you were able to pull out of something that challenging.
--- Quote from: willie on August 30, 2022, 11:40:37 pm ---for a first bow with 12" dedicated to the handle section, I would consider the shortening operation (from 77 to 66) be done further down the road as you see how the tillering goes. In fact, leaving the stave full width until you get it closer to final thickness and start tillering might make thickness reduction easier, depending on how you choose to reduce. band saw? rasp?
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I hear you on that, makes sense to be prudent. I do plan for mass reduction with a band saw, rasp and scraper to follow with more precision, and was planning on doing that pre-profile, keeping the waste, and using it as a support for each side to cut the profile. Would you suggest still cutting the pyramid [to 77] before tillering?
Alternatively, would there be a better length for the handle section? Shorter? I'm [kind of arbitrarily] using the dimensions from TBB1 in the spliced billets section - granted, that bow was Yew, and not as wide. Just curious as to how the handle length specifically influenced that advice. For what it's worth, I'm 5'7", so looking to have something that's not tooooo much taller than me for the field. I've seen other posts mentioning a handle section as short as 7" - would that be preferable for a target length of 66"?
Thanks!
willie:
--- Quote ---Would you suggest still cutting the pyramid [to 77] before tillering?
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sure. it gives you wiggle room in both thickness and string alignment. Its not the only way to do it, but if your profile is pyramid, and you do not plan to heat recurve the tips, then the design lends itself the possibility of a gradual reduction of the profile , which can happen as you tiller. You could even do the profile reduction after you reach full draw, a bit at a time until the limbs show set. It is much easier to tiller a longer limb to full draw without set than a shorter.
Did you see http://www.primitivearcher.com/smf/index.php/topic,61452.0.html
The pyramid design also lends itself well to using a Gizmo, as the desired bend radius remains consistent.
I think your handle length decision is well chosen for a first bow.
MattCav:
Again, thanks for the tips! [Maybe] last question before I start cutting - actually about the tips...
Given the slight deflex in the overall length, is it worth considering recurving the tips? I know there are obvious benefits in performance, and I feel plenty capable to do so, though I'm curious about "ideal" radius and length of the recurve if I move in that direction. I've also got those other billets I can work with later, so if this stave doesn't necessarily "call for it," then I know there's plenty of time to try it in the future.
Thanks again!
Beba:
Matt, welcome to this addiction.
Most difficult part of learning to build self bows for me was tillering. I second the recommendation for the tillering gizmo. Easy to make and use. You’ll find the build along and how to use on palioplanet. It will help develop your eye for tiller.
I like a 4” handle with 3” fades giving me a 10” nonworking handle section. Rounded corners make a fairly graceful looking back profile. I think it was Tim Baker in TBB1 that recommended the working limbs be equal to the draw length. These measurements would give you a 62” ntn bow. I’d recommend starting with at least the 66” you talked about or even 68” ntn. You can always take more wood off but putting it back on is another story.
I also agree with tempering the belly when the tiller is close to done. You can also add some back set at that point to get rid of the deflex your concerned about.
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