Author Topic: string follow(?) and recurving tips  (Read 2427 times)

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Offline luke the drifter

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string follow(?) and recurving tips
« on: February 13, 2010, 02:08:19 pm »
this is probably dumb question to begin with.  hypothetically,  i have a 68 inch hedge apple bow with a brace height of six inches(standard i believe) tillered to a draw weight of fifty pounds and a draw length of 30 inches.  when i finished the final tillering process, it had a string follow of two inches.  my question is this- can you recurve the tips to compensate for whatever loss of power/speed that this amount of string follow would inflict on the bow?   :-\ :) 8)

Offline dragonman

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Re: string follow(?) and recurving tips
« Reply #1 on: February 13, 2010, 02:20:26 pm »
if you got a string follow of 2 inches then the wood in the limbs was stressed a little more than it could take without suffering slight damage, if you recurve the tips now you'll  probably just overstress  the actual limbs more. It may then look like the tips are forward of the handle but there will  really be more set in the limb and more loss of power. Thats what I think, but I'm no expert.
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Offline Pat B

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Re: string follow(?) and recurving tips
« Reply #2 on: February 13, 2010, 02:22:28 pm »
By recurving the tips you are adding more stress to already stressed limbs and you will more likely add more string follow. Also for recurves to be effective you want a shorter, more highly stressed bow. When building recurves you want to design the bow for a recurve to begin with and not use them as a fix for a possible problem. Bow design is the most important thing to think about with the wood you have available and not use the wood to make a design you may want. That might work but your chances of success are higher if you properly design the bow for the wood.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline Del the cat

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Re: string follow(?) and recurving tips
« Reply #3 on: February 14, 2010, 05:59:11 am »
Like the guys have said, if you have already pushed the wood to the limit, you can't get any more out, trust me I'm sure we've all tried.
Typically what happens is you steam in some recurve at the tips, which either pulls back out again, or the limbs take more set so that the tips end up back where they were.
OK theoretically that may give you a tad more speed due to change of string angle, but it won't do much.
What it will do is give you some good practice at tip bending, and give you a good feel for that particular timber. It will also keep you out from under the wife's feet ::). ;).
Del
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Offline Ryano

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Re: string follow(?) and recurving tips
« Reply #4 on: February 14, 2010, 11:46:30 am »
On a bow that long I'd be more inclined to add some reflex through out the limbs with dry heat and temping it in.  I like to brace the bow backwards at a very low brace height like 3" and then cook the belly over the burner on the kitchen stove until its golden brown.  Then let the bow cool to room temperature and unbrace it. Let it rest for a day or two to regain some moisture, then start by working it in on the tillering rack again with a long string, until you get it bending enough to brace it again. Then take it back out to your draw length/weight on the tillering rack again checking for evenness and expect it to pick up a few pounds of draw weight. You may need to scape some to get it back to where you want it. This is the best way to get a wooden bow to hold unstrung reflex I have found.  ;D
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Offline Badger

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Re: string follow(?) and recurving tips
« Reply #5 on: February 14, 2010, 12:43:01 pm »
   If the wood was not completely dry when you tillered it the prognosis for repairing it is better. I like the tempering also with osage. Before heat treating myself and many others would do just as you are thinking and recurve them to make up for set, they would just take more set and end up in the same place. Steve