Primitive Archer
Main Discussion Area => Bows => Topic started by: CamSkye on May 21, 2017, 11:04:51 pm
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Hey there guys what's going on? So I have this sinew backed hackberry bow with heat treated belly that is 52 inches long, one inch wide handle which is 4 inches long, for 2 inches it fades into 2 inch wide limbs that then taper into 1/2 wide lever tips which are 5 inches long. Sinew backed with one layer, 2 layers on the handle. Basically I got the handle way to thin, its like 7/16ths of an inch thick, it also cracked in a little spot and is very weak there. I wrapped that area with sinew to help secure it. What I have tried to do to fix this thin handle is to just tie about a 3/4 inch thick piece of juniper tightly to the handle, unfortunately that didn't work and that spot that cracked continues to bend very easily despite the tied on piece of wood being there. So I need to ask for some help because I just don't know what to do. I don't think gluing a riser onto the handle is an option because the handle isn't perfectly flat it kinda has some slight dips in it. Hopefully someone can help me. Thank you.
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Build up a riser with leather of cork and let it bend with the bow.
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So do you build it up with glue or could I tie it on do you think?
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I've always glue leather on and I guess the same would be for cork. I guess you could tie it on to see how you liked it.
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You can use layers of wood laminations also. If you keep them thin, they should be able to bend to match the dips in the handle for a decent glue up. Several layers of wood will take some of the bend out if it's moving too much there. Gluing them instead of tying will do a better job stiffening the area.
If you wanted to stiffen the handle further to make it nearly non- bending, I'd place some flat pieces of bone on all sides of the handle. Then wrap it all up with wet raw hide. When the hide dries it should shrink quite a bit, squeezing the bone to the handle. Coat the whole thing with TB to water proof it and put your desired handle wrap over it when it dries.
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can you post a pic of the crack?
there are many options to build up an area, including laying down more sinew or other fiber
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Very interesting ideas guys. Sorry Willie I can't post a pic because the sinew wrap is covering it so that won't do any good. It's a pretty severe crack though. I appreciate the help guys.
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is the crack across the handle or along the length of the bow?
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Willie, the crack is all the way across the handle and it's about an inch long and it's cracked down pretty far, so it's extremely weak, I only strung it up once and it was an enourmous hinge.
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You had better use a rigid splint of some sort or that sounds lethal.
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Pat B, right, I think this hackberry stave was like 80 dollars or something so I really hope I can make this work, sinew is no big deal since I can just soak it off.
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that does sound pretty ugly. at first I thought that you had sinew on the back, but you say that you wrapped? it with sinew. like maybe around the crack? if so I would consider removing the sinew and making a patch on the back of the bow with a decent piece of wood. you would have to taper it in on the ends, but it would not hurt to flatten the back some and do it with a couple of thinner laminations. Del might come along shortly and link to some patches he has done.
Is it a sinew backed bow?
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Willie, the entire bow is sinew backed except for the lever tips, it's one layer of sinew on the limbs and two layers on the handle. I then wrapped sinew around the crack. So you think I should remove the sinew on the handle and then I'm assuming gluing a piece of wood onto the handle?
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The handle is less than a half an inch thick so I don't think removing anymore would be a very good idea.
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in TBB they talk about fixing hinges by patching plant fibers (flax, or hemp) on the back with glue. I guess it'd be titebond 2 or 3..
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Loon, good idea. Although two layers of sinew surely beats plant fibers in strength. I appreciate the help though.
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well, that advice was made when I thought the sinew was limited to a repair. now that i have read back to the first post and see the whole bow has a sinew back (sorry about the misunderstanding), I guess your options might be limited to applying more sinew, or at least some other fiber with the hide glue?, or removing the sinew to make a repair in the hackberry.
where there is a will there is a way.
actually, plant fiber can be much stronger, it does not stretch as much, but you are looking to stiffen, so plant would be a good choice. I would hesitate to use a different glue on the sinew if you might want to keep your options open for reuse of it.
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Willie, I'm not for sure but I think I don't need to strengthen the back anymore, I think I need to strengthen the belly by thickening it up with wood or leather like these guys said. Although I'm not one hundred percent sure. It just seems like the belly is going to collapse on itself, well I'm pretty certain it will.
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you might be well served to do a little of both, especially if the belly has been chrysaled or weakened. Did the sinew over the crack in the back look compromised? If not, then wood on the belly seems like a better plan. leather on the belly might not help as well.
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Willie, the sinew over the crack is not compromised. I have not bent the bow very much, only strung it to see how bad the hinge was. I would guess that only about 1/4 inch of wood is actually intact there so that's why it's bending so much. The leather sounds like a cool idea, think wood may work better though.
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Sounds broken to me :( :(
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reinforcing the belly sounds like your best chance of survival. I would do the feathered lament approach as previously mentioned. I wouldn't try removing the sinew on the back, but willie is right that plant fibers are usually stiffer than sinew. It's not just tension strength you have to take into account but its stiffness (young's modulus/modulus of elasticity). Gluing a thick layer of flax on the back of the handle extended a couple inches past the fades may stiffen up the handle and prevent it from bending as much. The problem is there's already sinew there, and I wouldn't remove it. Maybe if you treated the flax like sinew and just glued it down like another layer with hide glue (so you can harvest material if it fails) it might work. Regardless I think reinforcing the belly with real thin laminates would be the best option. if the belly isn't flat you can remedy that by cutting it flat. Cut through the sinew wrap, wood and everything. You're going to be adding material anyway so don't worry about it. it's probably your only hope. The leather and cork is a great idea for bendy handles that have integrity. That's what these we were imagining, but now it seems apparent that it's a weak hing at the handle, and will not survive without reinforcement. Like DC said, it's pretty much broken as is so prepare yourself for disappointment if that doesn't work. From what I'm gathering don't try to string it or draw it until repairs are made if you want any chance of it living. If the repair sounds too risky or inconvenient then I would suggest just moving on.
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Your best option would be to reduce the whole thing so that you have a thin sinew backed strip and glue an entire new belly on it from tip to tip.
Any talk of stiffening it with plant fibres on top of sinew or adding non-stiffening belly bulk won't change the inherent defect.
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I have not bent the bow very much, only strung it to see how bad the hinge was.
not drawn yet, so I see why your sinew might not be over stressed yet. drawing it further might be a different story if the crack is just under the sinew. building up the back of the handle was suggested to alleviate the tension at the crack. simply adding to the belly of the handle might not be enough.
However, in essence, I must agree with the others that the bow is basically broken, at least from your description, pics would be helpful for getting good suggestions. This does not mean that it cannot be repaired. A repair like PatM suggests, that replaces essentially all the cracked wood could be done. There might be a possibility of splicing in a new handle section without going tip to tip, the work required either way seems to be as much work to me as starting over with a new stave and salvaging your sinew for use on the new bow. One advantage to splicing in a new handle or creating a backing strip from your existing bow as Pat suggests, is that you could be shooting your new bow sooner without waiting for sinew to cure.
Either fix will give you experience in something new for sure, if you are up for the learning aspect of it all.
Some like the challenge, others do not.
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What I am curious about is why there is a crack there in the first place.
Even though there is sinew I would still be interested in seeing what it looks like.
There is the "possible" option of removing the sinew at the handle and gluing a couple very thin strips of wood over the crack, one on top the other, then reapplying the sinew. That fix would depend a bit on what the back is like. In any case fixing this problem is going to take some work
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I really appreciate all the help guys. I created the crack during the heat treating process, I tried to give the handle a bit of setback and it cracked on the belly pretty bad. Really great ides but I think I'll just leave my handles thicker from now on and slowly remove it until it bends. I ended up just cutting the handle so I'm left with two limbs, not sure if that was a dumb idea or not but I was thinking about making a 3 piece takedown bow with it one of these days. Thanks again for all the help, added to my knowledge for sure.
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(http://i623.photobucket.com/albums/tt320/bubncheryl/Mobile%20Uploads/IMG_20170327_195113786_zps1zkmirgx.jpg) (http://s623.photobucket.com/user/bubncheryl/media/Mobile%20Uploads/IMG_20170327_195113786_zps1zkmirgx.jpg.html)
Leather works great and flexes,
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I can't speak for anyone else but I was under the impression the the back was cracked. I read the thread again and can't find if you mentioned whether it was the back or belly. It makes a big difference. My answer would have been completely different if I had known it was the belly that was cracked. Moot point now though.
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None of the flexy build ups would work for this type of problem. They are only good for a bow that flexes correctly for the tiller and you want a conventional FEEL to the grip.