Primitive Archer
Main Discussion Area => Bows => Topic started by: PeteDavis on June 09, 2010, 10:43:40 pm
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I just tillered in a kit, red elm with a hickory back strip. Long bow, 1 5/8 wide and 67" ntn. I'll get some pics up when I get finished.
I glued this bow stave up with 1.5" of reflex. As of tillering in, it now follows the string an equal amount.
Is is possible to reduce this follow, by narrowing the limbs and making them thicker to achieve equivalent weight? I am building these kits long and wide now, because it's easy and somewhat safe and stable. Will branch out on the next one.
PD
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I am of the thought that thin and wide is the best way to keep string follow and set to a minimum so I think your original approach is best.
1.5" of string follow isn't bad at all. i think anything less than 2" is very acceptable. Maybe next time just introduce a bit more reflex to compensate.
JMO, other guys on here know WAY more than I do.
Mark
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Could you please explain trapping? This bow is just a tillered stave with string grooves. I have yet to glue a handle or final shape it. There's enough weight to spare, if I decide to trap the edges. PD
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trapping= when the back is narrower than the belly,giving the bow a trapezoidial (sp? word?) cross section
or it looks like a trapezoid
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You may have higher than optimum moisture content where you live. 10% or more is bad for set. Also examine your tiller and see if you used up all the available limb for bending. I tend to crowd my tillers as I like stiff outer limbs and stiff out of the fades and pay the price sometimes. Is your set equal throughout the limb or concentrated in small areas? Steve
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I kept the bend out of the handle mostly. Moisture is a real issue here, I live in Appalachia in a hollow with a creek.
Does elm get ansy with water??? I know hickory does. My backing strip is under 1/8th.
You guys are great!
PD
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Like the other guys sat it's the thickness that gives you set as there is more strain on the wood.
Wide is kinder to the timber.
A bit of set isn't really a problem, look upon it as 'conditioning' the belly.
even spring steel will take some set, ask the valve springs in your car.
If it doesn't have a little set then it's not working hard enough!
Del
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To answer your question, no. For the record, you have 1.5 in of set and no string follow in your situation. At any rate the set is caused by the compression and subsequent collapse of the belly cells. The amount you have is quite acceptable and may make for sweet, smooth shooting bow. There is a way to mitigate set. Since it is caused by the collapse of belly cells in areas where the bow is bending you can reflex areas that are not. In most bows that's the handle area and the last 6 inches of each limb. That will work for a selfbow. Typically , most glues don't take well to heat so in your case I'd just love with it, Pete. 1.5 in is an excellent amount and indicates the design is adequate. :) Jawge