Primitive Archer
Main Discussion Area => Bows => Topic started by: wood_bandit 99 on November 20, 2013, 10:28:38 pm
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When you are using a wood as a belly in a laminate, it seems people tend to not make sense as far as using the words growth rings and grain. What am I looking for that is straight? How do you see the grain is straight? Does it even need to be straight if your backing it with bamboo? Any help is appreciated. Thanks
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lll quarter sawn /// rift sawn = flat sawn that is what it looks like when you look at the end of the board. You want quarter sawn as the first option. When you get quarter sawn boards the grain will look like straight lines all the way down the board.
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People tend to confuse grain and growth rings. As Ed Scott said, the grain is when you take a piece of wood and split it which way the split travels is the grain. It really irritates me when some one looks at a piece of wood and says wow that has beautiful grain when they are really looking at the growth rings not grain.
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Whether you are calling them grain lines, or growth ring lines on a board, you want as little run off as possible. Bamboo backing will help you out, but it's not a miracle worker.
Tattoo Dave
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Follow a grain line as long as possible. Orientation of the board cut from the log is less important but 1/4 sawn is ideal IMO for a backed bow. if you can follow a grain line from one side of the board to the other and that distance is less than 12" I'd give the board a pass. 1/4 sawing helps in this regard.
if you look at the end of the board a quarter sawn board will have the grain lines all going vertical and perpendicular to the face of the board.
Some have said that grain dosent matter when backing with bamboo but it hasn't been my experience. Length of runout matters more than actual grain direction but the direction of the grain cane minimize or increase twisting.
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lll quarter sawn /// rift sawn = flat sawn that is what it looks like when you look at the end of the board. You want quarter sawn as the first option. When you get quarter sawn boards the grain will look like straight lines all the way down the board.
What bowman says is quite clear. If you use somewhat rift sawn which most boards are, the ones I have found anyway. You want at least 1 3/4" width or you end up with twist. If you use a 1 1/2" width board I would recommend slicing it down the center on the table saw and gluing it up so the grain is opposite on the 2 pieces. I have yet to get twist using this method on narrow bows.
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With quarter sawn stock, there can be no run outs. None. Edge Grain must be straight tip to tip. With the other 2 cuts 2 run outs per limb are allowed for 50 to 55 lbs.
I have never seen any one of the 3 cuts twist more than the others.
Jawge