Trad Gang
Main Boards => The Bowyer's Bench => Topic started by: CREEKBOW on April 13, 2009, 08:51:00 PM
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Hey gang! I'm getting into the final planning stages before ordering materials for my first Bingham Projects take down recurve. Should I build the limb jig and bow with 1 3/4 inch limbs or 2 inch limbs? What would be the advantages/disadvantages of the 2 sizes? I'm planning on building a 66" bow. I would appreciate any advice you could give me here.
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I'm a rookie as well, but the way I understand it is, depending on your target weight. The narrower/thicker limb will be a little easier to tiller with slightly less performance. Hopefully someone who knows more will give us both a better answer!!!!
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Have you discussed the bow you want to build with the folks at Bingham's? They have been building bows for longer than they have been selling supplies and have the info for you for the bow you want to build. After you get that one under your belt, then you can do some experimenting to see what bow style and construction method works best for you.
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My favorite recurves all have a narrow and deep profile (my top 2 are both under 1-1/2" at the fades). The limb mass is actually less in this config (twice as wide is twice as stiff, but twice as thick is 8x as stiff). You also get less wind resistance with the narrower limb (hey, it's a little more performance ;) ) So with everything else being equal (profile, tiller, etc) the narrower limb should perform better than the wider limb.
Downside of the narrow limbs? Less lateral stability and it's more critical that the bow be layed out properly. If you have a really extreme recurve that's not lined up properly you'll likely unstring the bow at the shot! One of the bows I spoke of above has a pretty extreme profile and is around 1-3/8" at the fades and taper straight back to the tips. The tips aren't any wider than most longbows. The other bow isn't as extreme, but the tips are narrower than most longbows! :)
Since they have all the formulas worked out, I'd go with the 1-3/4" sticking with Bingham's plans.
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Thanks for your thoughts, guys.
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I have built a number of TD recurves using Binghams patterns and methods and if you build the form properly you should be fine as far as limb twist goes. One thing I do think is an issue is that you build the form to the width you want the limb to be so you can make sure everything lines up in the form properly. What I am saying is dont make it 2 inches wide and then think you are going to make a 1 3/4" wide limb. You can do it but it is far better if you are just starting to make it easy on yourself
Good LUCK
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In my limited experience I have found having your form exactly 1 3/4 inches will insure proper limb/riser/ lam alignment. I couldn't do this with standard plywood widths. So what I did was divide the additional plywood thickness by 2 and rout that much off each side of the form at 3 spots along the limb and near the fades. If your riser block is more than 1 3/4 allow for that. Use 1 1/4 inch wasers of metal bar stock to keep everything in alignment. Be sure to wax everything well