Primitive Archer
Main Discussion Area => Bows => Topic started by: UserNameTaken on November 26, 2012, 07:42:14 pm
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I bought this really nice jatoba board the other day, thinking that I would make a D-section longbow out of it. But, I've been reading about this stuff on the message boards, and everybody seems to agree that this stuff chryssals badly. (i thought it would be like ipe.) I'm planning to back it with flax fiber, which is only going to make things worse. Does anybody have some suggestions for dimensions? Would heat treating perhaps help strengthen the belly so that it won't chryssal?
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I bought this really nice jatoba board the other day, thinking that I would make a D-section longbow out of it. But, I've been reading about this stuff on the message boards, and everybody seems to agree that this stuff chryssals badly. (i thought it would be like ipe.) I'm planning to back it with flax fiber, which is only going to make things worse. Does anybody have some suggestions for dimensions? Would heat treating perhaps help strengthen the belly so that it won't chryssal?
Check out my post: Maple / Jatoba ELB. I don't know how to post the link, otherwise I would. If anyone else wants to, knock yourself out!
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Here you go. http://www.primitivearcher.com/smf/index.php/topic,35352.0.html
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Hey, thanks. That's exactly what I was looking for. I don't suppose you remember how thick it was at the fades and tips?
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I've made a long flatbow out of the stuff. It came out fine. Didn't try a D cross-section though. The stuff is very difficult to heat correct.
Gabe
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Hey, thanks. That's exactly what I was looking for. I don't suppose you remember how thick it was at the fades and tips?
The handle riser on this bow is actually a glued on piece, to give the grip more meat. Otherwise, the grip area ends up being too thin and uncomfortable in the hand. It's just more jatoba, so it looks like the handle is one piece.
I believe I started out with 3/4" total depth before I glued on the riser. I taper the limbs to 1/2" X 1/2" at the tips, and then start to tiller.
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I've never had jatoba chrysall. I've broken a couple while tillering, but that was my fault, of course. I don't think it would heat treat very well, but I've never tried it. The last jatoba bow I made was a narrow ELB @ 48#, and it took no set.
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Thanks adb. I was kicking myself for buying this board, after reading all the uncomplimentary remarks about it on the message boards, but you give me hope.
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A pyramid bow would be less stressful in compression which would cut down the chances of chrysals.
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Jatoba isn't a bad bowwood, it's just less compression strong than you would expect judging its specific gravity. It's not as compression strong as ipé, but it's still capable of very nice longbow. Just design an ELB a bit wider than a typical ipé ELB could be and you'll be fine. Bamboo backing is OK, but leave the belly flat. I personally think a 'milder' backing such as maple or ash might be more suited.
Belly heat tempering is notoriously difficult and probably nearly useless with many tropical exotics; ipé, massaranduba and jatoba included.
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A pyramid bow would be less stressful in compression which would cut down the chances of chrysals.
Agreed.
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bowman, I thought that I might do a pyramid with the other half of the board, but I'm also going to try to get a longbow out of it; It would make such a handsome longbow. Since we're talking about it, how wide would you make a jatoba pyramid?
Darksoul, how wide do you think it should be? I was going to make it 1 1/8, like adb's bow, but I'm probably going to let it bend through the handle. I'll just build up the handle with some leather so that it doesn't cut into my hand.
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I've made a couple hickory backed jatoba longbows 1 1/8" wide, and they took about half an inch of string follow after starting out with 1" glued in reflex. They're nice enough bows, but if I do any more of them, they will be 1 1/4" wide to get away from taking so much set. Rob
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I've been making some awsome arrow shafts from jatoba. Hard as nails and heavy. Difficult to work with but pretty when done. I have some wood that might work for you as it is a bit lighter softer, but with stronger spine than Jatoba. It's called leopardwood.
ForresterWoods.