Primitive Archer
Main Discussion Area => Bows => Topic started by: bowman_137 on December 06, 2011, 06:19:18 pm
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I just finished my first bow, it is a red oak board bow that is 60" long. The first day i worked it slow and went out to shoot and it shot great but the next day I worked it a little bit before i drew back to full draw but when i finely got to full draw a heard a snap! I checked it out and found a crack in the top limb. Does anyone have any idea what i did wrong!?
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Without seeing it it is hard to say. Could be bad grain, wood too dry, poor tillering or just cause. Make your next one a little longer. Less stress on the limbs that way.
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If the wood is too dry, is the a certain method of re-hydrating it? If it was poor tillering then obviously its my fault. :-\
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The moisture content of the wood is directly related to the surrounding humidity. If you live in Arazona then it could get too dry. East of the Mississippi, not likely under normal conditions except in the dead of winter. Can you post pics of your bow so we can see the break?
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I will try to post pics tomarrow. I'm not sure if you will be able to see the crack in the pic but I'll try
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what there a hinge?
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Happens to us all on occaision, at least you got off a few shots.
Post a pic and we'll offer some sort of critique, to hopefully improve your chance of success on the next one.
It's just the hard school of experience.
Del
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Until I sat down with a bowyer who walked me through the entire process of making a bow, I broke every bow I made, including a hickory bow that I shot 200+ times before it broke. You got to hang in there and keep trying. Sooner or later, it will all come together. And you will have a whole bunch of fire starter and kindling while you learn.
I still ask questions and I am still learning, that's what makes it fun.
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I've made one board bow but from reading George's Site it seems the most important thing with Board Bows is choosing the best grained piece of wood. Keep it up, like George, I have a few holding up tomatoes and beans. ;)
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My guess is you made it too short and overstressed the limbs. You have to be spot on with your tillering on a short bow, one little hingy spot and BOOM! Make your next one 66" nock to nock, if you draw more than 28" make it 68" or 70" NTN.
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I'm a short feller I've got about a 26" draw. i took pics but the crack is so small you can't see it but ill post them anyway and see what ya'll think.
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Sorry the pic is so small too many megabytes..."what ever that is..." But i circled where the crack is hopefully that helps someone help me. I had to modify the pic a little bit.
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I have a 25" draw and never make a bow for myself shorter than 64" NTN. The old adage is "the longer the bow, the longer its life".
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Looking at your picture I'd wager that you did not have enough thickness in the inner limbs and given the abrupt transition at the fades, that's exactly where it would fail.
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Just my opinion, but it looks to me like your edges are to sharp. If you round the edges off they will much less likely to lift a splinter. The other thing I see is probably more to blame is the shoulder of your fade looked to be way to sharp of an angle. If you make the angle of the transition no sharper than 45 degrees. It will be much stronger . I could be wrong on how sharp your fade is, it's hard to tell without a straight on pic from either the back or belly. Josh
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Here's a different view. And a appreciate all the advice, the more the better off ill be. like i said this is my first bow and i didn't expect to get it perfect the first time. thats why i join PA because i knew i would get constructive criticism and learn how to do it right
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Is your handle glued on or just held on with the cord? It appears like the handle is to narrow and is bending to much, hence the splinter. On the next one make the bow longer, work on smoothing out your fade transitions, make your handle slightly beefier, and go slow. Good Luck!
Jon
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If that is the crack on the left side of your fade out in the last picture, it is not a fatal crack.
Looks like your handle isn't glued on. Take your handle off, soak the crack with super glue, clamp it closed until the super glue dries, glue, not wrap, a new handle piece on but extend it further down your limb and feather it into your limb with no abrupt angles.
I like to glue a couple very thin pieces on first when I replace a handle. These will flex with the limbs and won't pop the glue joint loose.
As the final part of the fix you can glue a thin strip on the back of your handle the same length as the belly piece to make a crack sandwich.
Broken bow recovery is a great learning tool.
Here is how you should feather your handle into the limbs, no abrupt angles.
(http://img.photobucket.com/albums/v181/ekrewson/bow%20making/bondofixhandle.jpg)
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Eric
That was kinda my thoughts also !
Guy
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yes i just wrapped the leather strip around the handle pretty tight. what glue should i use to glue the handle down iv tryed several different kinds and they just break loose? I'm sure some of that is because this bow needs more work and it has too many weak points. Also what tool did you use to feather the handle down like that?
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Handles break loose when you have too much bending in the fade out area or too abrupt an angle where you handle meets the limb.
I use Urac 185 for all my bow making but titebond should hold OK.
I feathered the handle into the limbs with a rasp, followed by a course file and finished up the transition with an orbital palm sander.
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All of the above contributed. The big ting is the fade area. The tapering needs to extend into the board itself. Jawge
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The is no fade, your bow is bending over an edge at the handle to limb point - just like putting a piece of wood in a vise and pulling back on it, or breaking a stick over your knee for a campfire. There will be much more stress right at this point. If you took the handle off and made a leather built-up handle that was soft, you may be able to super glue the crack and keep shooting. Good work making a bow and shooting it!
With the second picture I see your handle is narrowed. Repair it like Erik mentioned as you will need handle thickness so it does not break in this narrow area. The fade is the transition from handle to limb and is an area under extreme stress. Feathered transition instead of a hard point to bend across.
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Titebond is the last glue i tryed and it worked the best but I need to feather out the fades alot more i guess. So on my next bow would i benefit from not narrowing the handle?
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I think if you unwrap that handle and follow all the good advice you got that you can still get a good bow out of this one. Like Eric said repairing a bow is a good learning experiance and you will have enough people to walk you through it.
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Ok well thanks for all of the help! ill post more pics when i get further along with it or break it again, which ever comes first.
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A little more on feathering a fade. I shape this area before I start tillering so I have some extra wood to work with. I mark my 4" handle section before I start reducing wood in the fade and work the slope down to just above the limb's belly but stay off the belly.
It is real easy to dish out the transition area where the fade meets the limb if you are not careful so go real lightly with you tools. A dished out transition zone means a hing or much lower poundage bow than you planned by the time you straighten your goof-up out.
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As said above glue on two thin ( 1/8th) laminations on inbetween the riser you have and the limb. Let the whole lot dry properly then try and blend handle to limb just like in the above picture.
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It's sort of been said already, but I'm not sured it has been explained too clearly.
Sorry if I'm just covering the same ground.
Looking at the bow from the front or back it suddenly goes narrow for the grip.... fine
Looking at the bow from the side, the grip should slowly build up the thickness... but it must get thicker BEFORE the linb narrows for the grip.
If the narrowing from the side corresponds with the start of the thickening you have a sudden concentration off stress.
So as you come along the limb from the tip, it must gradually start to thicken and then start to narrow.... don't do both suddendly at exactly the same point.
Del
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Looks like you found a decent board :) nice straight lines :D
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Yeah the grain is pretty good in this board. I just went and picked up another one to start my second bow and its pretty straight too. the next one I don't think I'm going to cut out and narrow the handle maybe ill run into a few less problems! ???