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ipe instead of horn belly?
markinengland:
I have a similar one-day plan. I'd like to make a bow using Ipe belly and bamboo back with siyahs. I guess it would need to be made longer and maybe wider than a horn bow but the idea is stuck in my mind and I can't let it go!
Please post a build along as you go.
Mark in England
Dane:
--- Quote from: tom sawyer on May 09, 2007, 05:26:17 pm ---ATARN. And I have the Korean bowmaking DVD, it was informative.
My bow is upwards of 70lb@27". Its not really a specific design, and I cheated and used resorcinol glue on the oryx honr belly strips. Plus I used 1/4 horn strips and cut them in half and turned them so its really two thin horn pieces on each limb.
--- End quote ---
Lennie, thanks. If I can ask a few more questions, did you use a ratio of 1/3 each sinew, core, and horn? I guess the width and the thickness of the three components is what has me most hestitant to begin. As for layers, I am anticpating four or five layers of sinew, but will come to that when I come to that.
And last, I am assuming you attached the ears to the bow with fishtail joints (think that is what they are called). I'll use either ash or osage for the ears.
I'm going to use hide glue, being brave :), and score the horn and belly laterally per Jeffery Schmidt's video instruction. As I recall, some Turkish bows were constructured that way.
I think Medicinewheel is also about to make a composite bow. His bamboo wedge gluing technique is great, so thanks for that Medicine.
Dane
tom sawyer:
Dane, I used a V-splice with the siyah coming to a point. The siyah was taller than the core, I tapered it doen to the thickness of the core only at the tip. I overlaid the sinew over this joint. Also, since my horn strips weren't long enough to cover the joint on the belly side, I used a thin piece of walnut to bolster this area, and I wrapped sinew around the end of the horn on both ends. My horn was also too short to overlay the handle, so I uised a piece of osage as my spacer there. I used a piece of walnut on the handle on the back side, and went over that with sinew before wrapping the "fade" areas with sinew. I ended up covering the sinew with silk and painting that. I used black walnut for siyahs because it is lightweight, and I oriented the grain so that the grain runs parallel to the length of the siyah, not the bow. This lets the string pull against the walnut without it plitting into a particular ring. The string is oriented diagonal to the grain this way, I thought that was safer.
How much of each (sinew, horn and core) is the 64000 question. I used horn strips taht were maybe 1/8", I used a bamboo core that was something like 1/4", and I used a generous layer of sinew that probably dried down to about 1/8". This was for a 50" total length bow with little limb reflex and maybe 30 degree angles on the siyahs. It came out quite heavy, probably in the 80lb range. So I worked the horn belly some, it works well with a scraper. I beveled the belly too, and worked the sides a bit as well. Its still a bit stiffer than I like pulling, I measured it at 70lb but it may be a somewhat less than that now. Next time I'll use a slightly skinnier core. Someone else on ATARN made one about the time I was working on this, and it came out too light. I didn't want that so I intentionally erred on the heavy side. Keep in mind that longer means less hard bend and therefore thicker limb for a given weight. And wider means heavier for a given thickness. I "winged it" on this, but I have a little experience and did some reading first. You might want to copy a bow someone made or an artifact when you make one.
Dane:
Thanks for the advice and insights. It is all in line with my thoughts. I wonder what you would have ended up with if your core was also 1/8"?
The only certainty on my bow the dimensions of the ears, from an archeological find at Bar Hill, a bone stiffener from a Roman auxillary bow. My interest in Roman military archery is what really promoted me to think about composite bows in the first place. The other big Roman archery project I have right now is a scorpian I've begun construction on, but that is for another topic and time.
tom sawyer:
I thought about adding bone plates to the siyahs, it would be a nice touch. You'll probably want to reduce the thickness of the siyahs so the bone won't be adding weight unneccessarily.
Reducing the core to 1/8", is probably as good a guess as any. You'd leave the horn full thickness and just bevel the edges a bit. I'd be tempted to make it a little thicker, just because you can lighten it but you can't beef it up. And it takes relatively little reduction in thickness to effect a significant change in poundage.
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