Primitive Archer
Main Discussion Area => Bows => Topic started by: papoints on August 25, 2013, 11:48:37 am
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I am still trying to figure this bow thing out, lol. If I don't get it soon I think I will just knap somebody a five gallon bucket of bird points in a trade. :o I took some pictures of what I think is runout in the working limb. What do you guys do with this? Backing?
(http://i1134.photobucket.com/albums/m617/jhrper/IMG_20130825_102251.jpg) (http://s1134.photobucket.com/user/jhrper/media/IMG_20130825_102251.jpg.html)
(http://i1134.photobucket.com/albums/m617/jhrper/IMG_20130825_102224.jpg) (http://s1134.photobucket.com/user/jhrper/media/IMG_20130825_102224.jpg.html)
Sorry for the really crappy pictures. I am going kicking and screaming into the technology age. The grain seems to come to a V on the edge of the board. It just looks like it wants to be in two pieces. Of course that is where they all end up anyway.....
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You will get runouts in almost every board bow you build. Just by shaping the bows profile you cause runouts. The severity of the angle of the run out is the critical part of the equasion. The milder the angle the safer you are.
There is another grain runouts you have to consider also in a board bow and that is the grain that runs along the side of the board, running from the back to the belly or vice versa.
One way to deal with a runouts like you have in the pics is to round the corners which removes the point(makes it round) and softens the edges. By rounding these edges you not only lessen the chance for the grain to lift but also eliminate some dead weight. Those sharp corners do very little work, if any and are just extra weight being carried by the bow.
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Just get a stave ;) >:D
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Diddo on the points made about your bow.Then all you can do is to start bending her.A top view picture of the profile of your bow would help.You get grain run out on top view profiles of stave bows too of course but eliptical profiled bows will carry parralell width to midlimb most times to reduce the run out where the bow does most of its' work with less work and stress to the outers which will have most of the taper and like Pat said the lower the angle especially in the working portions of the bow the safer it will be.
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Thanks guys. I will round the board and get her bending. I think I see what you guys are saying about angle. Unfortunately this runout is right in the middle of a working limb. Oh well, I will give her a go soon and once it breaks I will put some pictures up then. Then I will get a stave....
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If she breaks, study the break and the forces that caused it. She will be a great teacher...broken or not. ;)
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Yeah looks like you got runout in 2 directions on that board......on the side and the front
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Spend the money on a stave and save your self some frustration. I see lots of busted board bows compared to staves on this sight. ::)
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From what I can see that board looks good but more pictures are needed, papoints.
Beginners should back their first few. Linen, silk, and burlap are good choices.
Long about '92 or '93 I made my first successful hunting weight bow. Followed quickly by several others. Then I ran out of log staves.
After I read Tim Baker's chapter on board bows in TBB 2 I headed to Home Depot and picked out a red oak board. I made myself a red oak board bow. I still have it.
I've never broken a board bow that I made provided I picked out the board.
Boards can make hard hitting bows provided the grain is relatively straight.
You can read the face of the board for flat (plain) sawn and rift (bias ringed) sawn.
Straight grained tip to tip. A couple of run outs per limb are allowed.
For quarter sawn look at the edge grain and make sure it is completely straight from tip to tip.
Do read Tim Baker's chapter. MY site has info too.
Boards are a good alternative to log staves.
http://georgeandjoni.home.comcast.net/~georgeandjoni/index.html
Jawge
http://georgeandjoni.home.comcast.net/~georgeandjoni/index.html
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Ok I took some more pictures. I think there is too much runout. I have made a couple of board bows but none of them are hunting weight. I have broken way more than a couple.... Once I got hit so hard in the stomach by the handle separating from the bow at the glue line it knocked the wind out of me. Haven't glued on a handle since lol. Thanks everyone for all your help and I might just back this one. Where do you guys get linen for a backing?
(http://i1134.photobucket.com/albums/m617/jhrper/IMG_20130827_204039.jpg) (http://s1134.photobucket.com/user/jhrper/media/IMG_20130827_204039.jpg.html)
(http://i1134.photobucket.com/albums/m617/jhrper/IMG_20130827_204106.jpg) (http://s1134.photobucket.com/user/jhrper/media/IMG_20130827_204106.jpg.html)
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Ugh yea .... With that much Run off a million dollars couldn't get me to attempt a bow from tht piece and a linen backing isn't gonna hold it together either but hey, I'm sure you can prove me wrong !!
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If the lumber store does not have any good boards, go elsewhere. From all the boards I broke so far which is about 7, I cannot say it was related to grain issues, just bad tillering and pulling beyond the target weight. All the boards had excellent grain structure.. ;)
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Yes, that one could be disastrous. Have you been to my site? Jawge
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Yeah George I have several times. I guess I need to go again :). Oh well, might make a bird house or something out of it. Thanks!