Primitive Archer
Main Discussion Area => Bows => Topic started by: Richard B on December 11, 2014, 04:20:19 pm
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To what extent should one follow the contours of the back of a bow when tapering the belly as opposed to evenly tapering out the grain. The bow I am working on at the moment has a number of dips and humps on the back. In general the grain is tighter in the dips and coarser in the humps. I have read that this will make the wood stronger in the dips and weaker in the humps, which would suggest that following the grain rather than strictly going for an even taper in relation to the back would be a good idea for an even tiller (which is what seems to be happening with my bow). The problem is that you then end up with thin spots around the dips, which make me a bit nervous.
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If the humps and dips are pronounced the back and belly should be in concert. What the back does the belly should do too. Jawge
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What wood are you using? Thin spots at the dips are to be avoided. When I tiller vine maple with lumpy backs, I make the belly follow the dips and constantly measure thickness to avoid thin spots.
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yes make the taper even,,
if the grain is not even, you may not be able to have an even taper on the grain..some staves are like that
the thickness of the limb and how it is bending or working trumps what the grain is doing
you want the limb to work evenly,,,if the way the grain looks is not coinciding with the taper or even tiller,, go with the taper and even tiller :)
those staves can be tricky,, cause a deflex spot can look like a hinge,,and will trick the bowmaker into making a stiff spot there,,and when reflexed can trick the bow maker into making that spot to thin,, to make it" look right",,,,, you need to go with the even taper on these spots so the wood works evenly,,,even if it does not "look right"
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yes make the taper even,,
if the grain is not even, you may not be able to have an even taper on the grain..some staves are like that
the thickness of the limb and how it is bending or working trumps what the grain is doing
you want the limb to work evenly,,,if the way the grain looks is not coinciding with the taper or even tiller,, go with the taper and even tiller :)
those staves can be tricky,, cause a deflex spot can look like a hinge,,and will trick the bowmaker into making a stiff spot there,,and when reflexed can trick the bow maker into making that spot to thin,, to make it" look right",,,,, you need to go with the even taper on these spots so the wood works evenly,,,even if it does not "look right"
+1 :)
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Use your thumb and forefinger to tiller. Run them down the length of the bow as you remove wood. They can feel differences in thichness within thousandths of an inch and are my most used tool! Once you get a feel for how to feel the taper its pretty much fool proof for never getting a hinge again.
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The belly grain rarely, if ever, lies. If the bow was taken from stave properly you will have growth rings feather out as the thickness tapers, usually 2-4 rings per limb. Each ring ending being easily visible. Those same rings will tell you if your side to side is correct as well. If that "feathering" effect isn't centered, your thickness is probably off from side to side. Im a grain reading fanatic from stave to bow, as a result my tillering has improved. Cody mentioned using your fingers to feel each side, great skill to learn as well.
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I was wondering when someone would discuss this info about grain....good point, great info Pearl and Cody(missilemaster).
DBar
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Use your thumb and forefinger to tiller. Run them down the length of the bow as you remove wood. They can feel differences in thichness within thousandths of an inch and are my most used tool! Once you get a feel for how to feel the taper its pretty much fool proof for never getting a hinge again.
The best way to tiller I think. Cody showed me this a few years ago and i rarely use a tree with pulley anymore.
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The last two bows i've made with friends the grain has 'lied' (both elm staves). Never rely on just the grain it's the whole package that matters.
If you trace the outline of the back onto your tillering board before tillering you can see exactly where a bow has taken set eg. changed from it's original shape in the blink of an eye. Set is the real unmistakable teacher when it comes to assessing correct tiller.
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Cody is spot on. That and constantly check BOTH sides of the limb You're working - having a different thickness (side to side) is a common mistake. Bob
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Dark room sweet music, glass of wine, run finger and thumb along the limb.... >:D
Works for me :laugh:
But seriously I think a lot of people these days don't know how to actually see and feel... they look but they don't really see. (Prb 2 bsy txting)
Del