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Main Boards => The Bowyer's Bench => Topic started by: spils on November 21, 2020, 12:33:54 PM
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Hi, as the title says, I'm brand new on this forum and a total neophyte in bow building.
I've been working for a while on my first bow for my daughter and am having some issues. It's a maple board longbow, 60" and was hoping to get between 30 and 35 lbs draw weight for her.
I was getting close to the draw weight for the bow, but then saw I had developed a lot of limb twist, with the top and bottom limbs going in opposite directons. In trying to correct the twist, I've dropped the weight down to 25 lbs and I still haven't eliminated the problem completely.
I know this is my first kick at the can and realise that Steph's bow Mk I will probably end up as kindling, but if I can get any advice for Mk II I'd appreciate it!
Thks,
Spils
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Hey spils, welcome. There are some expert self bowyers here who can surely help you.
Might be helpful to post some pics of the twist and wood grain of your bow.
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Welcome to the Bowyers Bench, spils
Sounds like uneven thickness across the limbs. This is a typical situation if you use a vice mounted on a bench. You end up with one side of each limb thicker than the other and when you turn the bow around to work the other limb you end up with the opposite side thicker. As you draw the bow the thicker side is stiffer and causes the the limbs to twist and with the other limb thickness opposite causing it to twist the other way resulting in a "propeller" twist.
As I work a limb down I constantly use my fingers as a thickness gauge sliding my hand with the limb between my thumb and fingers feeling the thickness across the limb but also along the limb looking for thickness difference along the length. You can feel a thickness difference better than you can see it.
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Welcome. Where in Ontario are you?
Dave.
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Thanks Pat for that. Sounds like the vice could be my problem, even though I tried to be as even as possible. Good lesson learned on a twenty dollar stick of wood! Any thoughts on salvaging what I can out of this one?
Hi Dave, I'm southwest of Barrie.. not too far from Orangeville.
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The good thing about selfbows they shoot pretty well even with some twist. If the tiller is otherwise good, shoot it.
Will you post pics, braced, unbraced and drawn?
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We’re about an hour apart. Did you say that the piece of maple for your bow cost $20? That’s a lot. Are there any sawmills or wood retailers near you? I stay away from buying wood from the big box stores. They’re way overpriced.
If you have a table saw or bandsaw and a jointer/ planer you can get rough wood and cut to the exact size you want.
I’m lucky to have a wood retailer close by and other options within an hour’s drive.
Barrie is a big place. Anything there, or just big box?
Dave.
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If you are reducing the limbs with a rasp here's what ya do. Draw a line say 7/16" from the back of the bow on both sides of both limbs and draw a centerline down the belly of the limbs. Now rasp off the wood between the line on the edge of the limb and the centerline mark, do this on all four sides. This gives a peak in the center of the limbs. Then remove the high spot or peak in the limb down to the edge. This works good for beginners to get the thickness even. When you think it is flat you can use a cresent wrench to check it
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What bubby said! :thumbsup:
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Thats great advice, thanks! I'll give it a try, will definitely post the results.
Dave, I have an nice specialty lumber yard about 45 minutes away.. Century Lumber. Ive already bought a few nice pieces of wood to use once I've built up some skill. ts nice stuff but a bit
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Its a bit expensive. Barrie has nothing but big box sadly, at least as far as I can find
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Go get permission from someone you know with land to cut a tree or two for a case a beer etc...you should have plenty of elm,hophornbeam,hard maple,oaks,black locust etc around you. Much cheaper to learn on,and more fun imho than 20 dollars a pop on trim boards. Just a suggestion...