Primitive Archer
Main Discussion Area => Bows => Topic started by: Colindemo on December 19, 2014, 04:26:13 am
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I'm planning on building a hickory longbow from a board but i was wondering whether it would need a backing or not. The grain runs straigth trough the board but not perpendiculair to the surface of the board but diagonally, i hope you guys understand what i mean. I've read that hickory is in itself good for a backing but i would imaging that such a backing would comprise only one growthring.
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Most hickory backings are cut on the edge (quarter sawn) so you see a series of rings looks like this |||||||||
Del
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Grain orientation doesn't really matter. What really matters is that the grain is straight on all four sides. Some run off will be ok as long as it's gradual and not concentrated in one area.
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Here are some pictures to clarify what i mean. What would be the maximum drawweight before i need to add a backing? I can't imagine that a grain that's diagonal trough the board doesn't matter at higher drawweights.
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It looks like your grain is riff cut.////////// not quarter sawn ||||||||| but that can be ok!!! I just made a hickory board bow that's riff cut. It is 75 lbs at 31 inches 73.5" ntn, ELB style, no backing used!!! shoots sweet!!! cheers fiddler49
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The grain orientation for the. Back is the most important!it should look something like this.this is maple though.
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Here are some pictures to clarify what i mean. What would be the maximum drawweight before i need to add a backing? I can't imagine that a grain that's diagonal trough the board doesn't matter at higher drawweights.
There are two kinds of things people refer to as 'Grain". One is the growth rings. The other is the radial grain. If you let a log sit out, you will see little splits develop in the ends, These splits will extend out from the center of the log like spokes of a wheel. You can split a log along these lines, and as long as it follows that radial grain, the back will be ALMOST as strong as an intact growth ring, because the fibers are separated, not cut across. In fact, if you follow the fibers, any angle is ok, but you MUST follow the fibers.
You can make horrendously powerful bows from boards, without backings, as long as the back follows those fibers. This is why only one board in 50-100 will make a bow. How strong a bow you can make depends on design, and quality of the board, not on raw draw weight. Any bow will break iff made too strong.
So, with the board bow, sans intact growth ring or backing, make it as strong as you want. *BUT* do so by making it wider. If a perfect stave of hickory with an intact growth ring will make a 50 lb bow 1-3/4" wide, then the same wood, quartersawn into a board stave, will make a similar-tiller bow 2" wide at the same poundage. And it will make a 70 lb bow if made LONGER or WIDER.
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Rift sawn, flat sawn, 1/4 sawn - does NOT matter.
Look along the length of your board not just the end grain.
Are the lines straight? On all four edges? Your photos don't show anything needed to access the grain.
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Mike is right. Smooth the face of the board with a scraper or sandpaper, wet it with alcohol or paint thinner, and take another picture for us. If you can see growth ring lines running down the face and edge of the board, and not running off, you'll be ok.