Primitive Archer
Main Discussion Area => Bows => Topic started by: Kegan on October 12, 2007, 07:35:47 pm
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Okay, I've been reading, Pope's Hunting with the Bow and Arrow, and The Bent Stick, and have a question: Is a slightly rounded belly a good thing? If one were to build a low stress bow, would a rounded belly be a good choice for it? I beleive Dean Torges suggests a slightly rounded belly in his book, Hunting the Osage bow. Most of the time I hear bowyers say that the belly should be perfectly flat to reduce stress, but if you have a nice long, flat D bow, would a slightly rounded belly help in perfromance/set? I know it isn't as durbale, but would it help perfromance in under-stressed bows ????
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Define "Good Thing." Yes theoretically a perfectly flat belly is the least stressed design. A more or less rounded belly is much easier to create with hand tools and I think is prettier, too. A slightly rounded belly is probably a good crompromise with most woods. Of course , if you're working a wood known to be weak in compression and prone to chrysal perfectly flat would be best. With stronger wood you have more options. Ron
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.................Ya cant make a perfectly flat belly with hand tools. The only way ta do this is with a planer/joiner-gasp ! :o so any bows ya have made didnt have perfectly flat bellies. Some woods chrystal no matter what ya do. Try makin' whats called a "backwards" bow sometime, will answer all yer questions. ;)...........bob
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kegan i build all the stone bows i do have rounded belly's and the ones i do with steel get rounded bellys too. does it do something, i dont know. i fail to see how any stave bow with a flat belly is gonna be better than the same stave with a rounded belly when the bow will have a crown on the back. in order to utilise all the wood evenly you would have to concave the belly. anyway its the 10,000yrs of bows prior to modern day bows that im sticking with. peace
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Its interesting what some experimentation can do. I have a lot of osge from a big old tree that turned out to be pretty sub-optimum stuff. Thick layer of early growth in the ring versus late growth, this stuff has density more like red oak than good osage. I found that flat bellied selfbows from it were practicaly worthless. You had to go way to thick and wide, compared to regular osage, to get draw weight out of it. However, I find that if I make a mini ELB, very rounded belly, 64" long, it makes a smashing bow with lots of zip.
Dave
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I use a straight-edge scrapper on the belly which does allow for a fairly flat belly...although not perfectly flat. I personally like the rounded look better from a cosmetic view. If possible I try to leave a few pounds of extra draw weight above what I want to enable me to radius the belly edges and allow for whatever the bow will lose in weight while shootin' it in.
While tillering I concentrate on keeping the limb thickness the same from side to side if possible. I've made one D-style bow which forced me to remove wood working the belly radius during tillering. I found this more difficult then using a straight-edge scrapper while the bow was vised. :)
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Hmmmm...how did those cabinet makers make perfectly flat surfaces BEFORE the invention of the planer or joiner? Kowechobe?????
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Dave, that was a good observation you made on the weaker osage. It does make good elb designs, From what I have experienced it is very elastic and the narrow thick crowned belly designs seem to agree with it very well. Steve
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Cabinetmakers didnt make perfectly flat surfaces before the modern tools when they only had hand tools silknstring. Check some furniture ya will see. Not the point of thread anyway movin' along.......bob
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I think some bow woods perform better with crowned bellies and some with flat bellies. In my experience most osage likes at least a slightly crowned belly and most white woods prefer a flat belly. Pat
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Just curious...no need to be defensive bob. Dang thin skins around here sometimes. I prefer a slightly rounded belly on the bows i make. I have heard that even in compression strong woods a rounded belly works best since it reduces the tension forced onto the back. Is this true/have any merit?
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Not bein' defensive just was answerin' ya question silknstring ;) an thin skinned hmm, sometimes but not most ;D....bob
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Well at least I spelled your name correctly...care to comment on my last question about tension versus compression?
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Hmm, I like a slightly rounded belly on my bows. Have merit ? I think so. Does it reduce tension load on the back and is this true ? I wont make a blanket statement here but for me it works and I do think it helps reduce the tension load on the back for less than really good woods. I even like it on hedge and hick and persimmon, so go figure. Just like it I guess and like the way it looks as compared ta a flat(ever close) belly. Personal preference like the man said "Everybody's got one, nose that is !" ;D..........bob
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You can make a flat surface with hand tools. Use a cabinet scraper and bow it slightly so that you are putting pressure on the center rather than edges. If you can make it hollow, you can make it flat.
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You can make a flat surface with hand tools. Use a cabinet scraper and bow it slightly so that you are putting pressure on the center rather than edges. If you can make it hollow, you can make it flat.
What is flat ? Care to explain ?How do you bow a cabinet scraper ta put pressure on the center not the edges ? Care ta explain ? Do you mean "relatively flat and not perfectly flat ?"........bob
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I can't speak for others, but when I talk about a flat bellied bow, I mean relatively flat. Not fiber glass bow flat. I do think that handtools can come close to real flatness, but it's a lot of work. Cabinet scrapers, small planes and spoke shaves all can be used to flatten the belly. Ron
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bob I guess if you put a mike on mine they ant PERFECTLY flat but they are flat
none the less.I round a few if need be but mostly I make them flat,like you said
everybody has one and that is mine.I like to keep the limb the same thickness
all the way across and rounding the belly won't do that if the back is flat
well [kind of flat]nothing is prefect in selfbows.If I have a dip in the back I
round the belly accordingly if the back is rounded I dish out a little also.seem
to work for me. ;) :)
Pappy