Primitive Archer
Main Discussion Area => Bows => Topic started by: barebo on January 03, 2010, 09:52:12 pm
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I was just checking out the thread by bigcountry regarding his tiller. ( Great looking bow !!!) George has made reference before to getting the limbs bending right out of the fades. What I'm wondering is this: when you are making a long, narrow bow, does the same principal apply, or having longer limbs, can the fade area not be as critical to get bending as much ??
This is my first Ipe - backed with White Ash left in stave form (not planed to board form - bark removed and flattened on jointer)
I have a nice even taper from the fades to the tips on the Ipe belly, and it's bending in a fairly even arc now. The dimensions are
70" ntn - 1-1/8" at the fades with a straight taper to 7/16" tips. I'm sure that I can thin the tips some.
What tiller profile should I be looking for ?? Up till now I've made flatbows of Maple, Hickory, Black Walnut, and Ash. This Ipe is a different animal no doubt. The stiffness factor (tensile strength??) is amazing. I'll try to get a pic or two soon. Any advice on what to shoot for tiller wise is appreciated.
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What George mentions is sound advice no matter the length of the bow. By leaving the fades stiff you are in effect creating a bow with a really long non bending handle as opposed to a shorter non bending handle. It is true that a longer bow is more forgiving of this because you are eliminating a smaller percentage of the bending limb. The real advantage to a long bow is having more bending limb which is more forgiving of tillering mistakes. By leaving a long bending handle you loose that advantage and might as well build a shorter bow.
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So you're saying that I should start it bending right out of the fades, and then the limbs will have more wood doing less bending??
That makes sense - my handle on this one is pretty short - from fade to fade the "stiff" section is only 8" total. As this is a spliced bow, I wanted to leave the section in front of the fades a bit "meatier" to keep it strong there. I just used a 45 degree splice, so I'm a bit cautious . Maybe having it bend at the fades will actually put less stress on the handle area?? Guess I need to try to get a pic up.
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If you leave 1 inch on either side of the splice stiff you are safe. The longer limbs will without a doubt take some stress from the joint. This bow is pretty dang long so you can tiller it as you choose without ill effect, but I still like Georges advice.
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I'm with you 100% on George's advice - I made a fairly long Maple bow - 67ntn - last March, and after reading one of his posts advising someone on tiller, decided to give it a shot. It worked great !! I only posted the question about this one(Ipe) as it's such a
different feel and almost seems way underbuilt. I might have to rely on a "tiller gizmo" for insurance. Never used one, but it makes sense.