Primitive Archer
Main Discussion Area => Bows => Topic started by: Lorenzo on November 10, 2021, 05:56:02 am
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A friend of mine asked me to make him a 30 pound @28" shortbow.
I produced one but it draws 40 lbs at 28". I need to take away 10 lbs without losing too much time or risking to alter the tiller too much in the process...
Yesterday I took away about 3 lbs with the drawknife but since the bow is already basically finished every time I shave away with it alters the tiller a bit and I have to retiller too often for my liking.
Shaving away with a knife or scraper allows you to keep the tiller better but you remove less material and it takes a lot of time and energy.
I was thinking about hand sanding with heavy grit paper but that also takes a long time, unless done with a power tool, which I am very skeptical about using, also because I like to keep everything hand-made.
Is there a cost-effective solution for this kind of operation?
Thanks for the insight
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Quality light bows are a pain for me anyway. If it’s has a good tiller choose the tool of choice and count your strokes on each side of the limb and repeat till you reach desired weight . Also rounding the belly is easier but might take more set. Just part of tillering. Arvin
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Narrow the width by 25%.
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I use an orbital sander and work the limbs and fades, any wood removal in the fades seems to drop poundage fairly quickly. !0 passes with an orbital sander with 120 grit paper usually drops about one pound for me.
I continually check with my tillering gizmo and sand any limb marks slightly more than the rest of the limb.
I stop sanding when I am about 3 or 4# over target and shoot the bow in all over again to see how much poundage drops during shoot in. When I made bows for people I would try to give them a bow that was 2# over target because I knew it would drop a little more with a lot of use.
When you get into the lower poundage bows the weight comes off very quickly so I would not make 10 passes with a sander if you should try one, proceed cautiously.
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If the limbs are well tillered you can scrape each limb, full length and the same amount for each limb. after a few scrapes exercise well and check the weight. It shouldn't take much scraping to get the weight down. Do keep eyeing the tiller as you go so the bow doesn't get out of whack.
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Buy your friend a cheap set of dumbbells.
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Buy your friend a cheap set of dumbbells.
Good one.😁
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no its not easy,,the more experienced you get,, its even more difficult,, because you get pickier about the end results,, :D Dan Perry did suggest side tillering to reduce weight without changing the tiller,,
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I’ve had my best luck side tillering. Doesn’t take much
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Narrow the width by 25%.
+1. This is the easiest way to adjust weight without messing up the tiller. Keep in mind that 25% is 25% of the width at each point, not a fixed width along the full length of the limb. If a fixed amount is taken off the width over the full length then the tiller will be very messed up.
Mark
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Narrow the width by 25%.
+1. This is the easiest way to adjust weight without messing up the tiller. Keep in mind that 25% is 25% of the width at each point, not a fixed width along the full length of the limb. If a fixed amount is taken off the width over the full length then the tiller will be very messed up.
And it could get to narrow and take set if the design was already as wide as the wood will allow . There lots of ways to skin this cat . Including trapping the back.Arvin
Mark
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PatM: laconic, accurate ;D
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And it could get to narrow and take set if the design was already as wide as the wood will allow . There lots of ways to skin this cat . Including trapping the back.Arvin
It won't take any more set than it took getting to 40# @ 28" because the limbs don't bend more when it is narrowed, they just generate less draw force at the same bend. It could get too narrow near the tips and become weak or unstable, though.
Trapping hasn't been mentioned and that is another good option if done carefully.
Mark
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And it could get to narrow and take set if the design was already as wide as the wood will allow . There lots of ways to skin this cat . Including trapping the back.Arvin
It won't take any more set than it took getting to 40# @ 28" because the limbs don't bend more when it is narrowed, they just generate less draw force at the same bend. It could get too narrow near the tips and become weak or unstable, though.
Trapping hasn't been mentioned and that is another good option if done carefully.
Mark
That's the way.
It would only take 30 minutes or so. Very easy to reduce width compared to thickness.
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We'd need to know the length and current width of the limbs before truly reaching a solution. At least one not involving light weight training.
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We'd need to know the length and current width of the limbs before truly reaching a solution. At least one not involving light weight training.
No, we don't need to know current length or width. For ANY length and width, narrowing the working limbs by any fraction reduces the draw weight by the same fraction.
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True but lateral stability could be at stake for narrow bows.
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In the end I did with a very sharp knife.
I kept the bow strung while shaving so that I could check the tiller as I went.
I opted out of the width reduction because I wanted to keep the limb as flat as possible. Being this bow only 130 cm it would have been quite safe to do anyway.
It turned out well, thanks for the advice.
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We'd need to know the length and current width of the limbs before truly reaching a solution. At least one not involving light weight training.
No, we don't need to know current length or width. For ANY length and width, narrowing the working limbs by any fraction reduces the draw weight by the same fraction.
Still need to know in order to determine if the bow is underbuilt or overbuilt. If he said the bow was less than an inch wide already and 56 inches long, would you narrow it?