Primitive Archer
Main Discussion Area => Bows => Topic started by: SpringyWoodPassion on November 30, 2021, 08:55:06 am
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Like stated in the title.
I was hoping that B. Locust selfbow would have some performance, but it developed these compression cracks (about 2" along the belly) during the tillering process.
The bow is 62", the limbs are about 2" wide. I was going for at least 35#.
Should I bother to fix it somehow, or is the bow going to break right where the cracks are?
This isn't the first time B. Locust staves developed compression cracks like that, while tillering and excercising the limbs. It can be really frustrating and I'm starting to have doubts about B. Locust being a quality bow wood species.
Thanks
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RIP! Black locust is susceptible to fretting so all precautions should be taken when building a BL bow. Try building one longer and wider. If you can achieve that make the next a little shorter.
I had similar bad luck with black locust early on in my bow building and I quit using it for years until I was confident in my craft and still fretted it.
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I've had the same problem with a cuple of bows I made and from my experince I can tell you that black locust is a good bow wood, but it does not forgive any tillering mistakes you make. Another problem I found with it is that a too high humidity content of the wood makes it even more susceptible to compression cracks. A light heat treating worked well for me, making the wood a little more compression resistant. Unfortunatly I don't think that your bow is salvageable, those are a lot of frets... I'd suggest you to start again with a wider stave, season it very well, take off the sapwood and when it's thin enough to start bending heat treat it.
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Thanks a bunch my friends. I still have a few B.L. staves, but guess I'll stay away from them for a while.
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Normally b.locust bows are made from all heartwood. Chase a ring for the back like you would with osage.
black locust is a wonderful bow wood. Definately right up there with the best of them. BUT you need to understand its properties and do a very good job at tillering. Always pay very close attention to spotting weak areas early and never pull further until you have fixed it. It is a strong in tension wood that prefers a flat belly and a crowned or trapped back.
You appear to be using a rounded belly on a stave from a small tree. As you are tillering and removing wood you are losing all your heartwood. This is a recipe for disaster with locust!
If you have more staves from small diameter trees. Rough out your width then chase a few rings off the back, try to estimate how far to go so that your belly will be all heartwood. You can use sapwood rings for the back if needed.
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It is a strong in tension wood that prefers a flat belly and a crowned or trapped back.
You appear to be using a rounded belly on a stave from a small tree.
Thanks. What is a trapped back. Forgive me the question, but I'm a novice. Thanks
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Tapering the edge of flat back limbs toward the middle of the limbs on the bow's back . Thus making it more like a crowned back. You end up with a wider flat belly, and the top tapers toward the middle of the limb. Great advice from bownarra.
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usually you have to remove the sapwood. you often have compression cracks with black locust but you have not much heartwood and thats a problem
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Tapering the edge of flat back limbs toward the middle of the limbs on the bow's back . Thus making it more like a crowned back. You end up with a wider flat belly, and the top tapers toward the middle of the limb. Great advice from bownarra.
So why is it called "trapped" back and not "tapered" back? Again, forgive me the question if it sounds too obvious to some of you. I'm a novice.
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It's called "trapped" because the cross section of the limb is trapezoidal in shape.
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It's called "trapped" because the cross section of the limb is trapezoidal in shape.
Thank Pat B. I get it now. I thought trapped crown had something to do with "trapping" or something.
So the trapezoidal crossection should narrow toward the back in a B.L. bow and should start to taper this way from mid limb towards the tip, right?