Primitive Archer
Main Discussion Area => Bows => Topic started by: dean on October 16, 2011, 01:59:43 pm
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I've got a few knots on the back of a stave I've been working on. I've seen some finished bows with knots on their backs. How do I deal with the knots without compromising my bow?
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As long as you don't violate the rings around the knot and have plenty of wood around them they shouldn't be a problem. That area of the limb(s) will probably be a bit stiffer as you tiller.
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I do'nt do anything special just build my bow.
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First thing that came to mind was to ask you what type of wood it was. Then I smacked myself on the head and said, "That's a stupid question, John, duh! Doesn't matter what kind of wood it is, you just don't violate the growth rings, especially around knots."
I usually leave a raised bump overtop of a set of pin knots or whatever knot is on a limb. I do this by carefully chasing one good growth ring across the whole bow, taking extra time and effort around getting that knot's growth ring exposed. Sometimes I have to go so far as to use a set of tiny carving knives and dental picks to follow that growth ring around the knot. Then I draw a circle around the knot with a pencil and leave everything inside the circle while I go down to the NEXT ring. That way I have an extra cap of wood over the knot to hold down splinters, etc.
Now when you define the edges of the limbs, be sure to follow the grain of the wood. The grain lines are the lines that wood naturally splits along when a log is split out, like for firewood or for fencerails. The grain of the wood will probably flow out and around the knot just like a little creek will split and widen out around a rock in midstream. If you follow that grain like gospel and treat it right, the bow will remember this and reward you for it.
That's what most people mean when they say leave a little extra wood around a knot. Lastly, leave a little extra on the belly at that point, too. It should show as a bit of flattening in the curve of the limb when the bow is drawn, a flat spot. Yeah, you heard right, you don't want perfect tillering and perfect arcs on a limb with a knot.
Clear as mud?
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Very good advice JW. ;)
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So what...ya got a couple knots.....so work "around" them...lol :laugh:
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I'm not really a fan of leaving extra rings around knots. I know it can be (and is!) done this way but I much prefer to have a single ring for the whole back and where there are knots I leave a little extra width. As much extra as the area the knot covers. This way there are no spots where a splinter can lift and the knot isn't taking any more 'load' due to the extra wood. Imagine you've got a perfect whitewood tree with knots - you remove the bark and make a bow - the back isn't going to blow - no 'extra' ring. If you were working an osage stave down to one ring you wouldn't decide to have a 'step down' to the next ring mid limb....
Just my thoughts ;)
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dean, most knots do need some type of additional treatment. I usually take the knot down to the same in when I can and compensate with additional width letting the grain swirl. If I can't leave wood on the width then I try to leave some on the belly. I try to tiller so that the knotted area stays slightly stiffer than the rest of the limb. Just a bit. Jawge