Author Topic: When backing overpowers a bows belly, what does it looks like? ...  (Read 2250 times)

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Offline toomanyknots

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Does it crush? Does it brake? This happen to anybody on here? Excessive set? I know that you can get chrysals, but do chrysals always lead to failure? And who the heck came up with the word chrysals anyway... :) Wierd word.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline Boofus

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Re: When backing overpowers a bows belly, what does it looks like? ...
« Reply #1 on: November 03, 2010, 05:17:13 am »
I had this happen with a sinew-backed osage bow, I had 10" of reflex in it (clearly too much) and yes it chrysaled first, then a small piece of the belly actually split off, but the bow still works! I actually harvested a doe with it too! When i get a chance i'll post some pics of it so you can see what it looks like.

Offline Pat B

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Re: When backing overpowers a bows belly, what does it looks like? ...
« Reply #2 on: November 03, 2010, 09:25:42 am »
You can get frets or excessive set or both.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline toomanyknots

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Re: When backing overpowers a bows belly, what does it looks like? ...
« Reply #3 on: November 03, 2010, 10:44:07 am »
Ohh, it makes sence you might get set. It seems like a strong backing, especially one that doesn't stretch much like flax or linen, would stop the back from doing as much work. Like the wood wouldn't stretch as much as it would without the backing. So that forces the belly to be compressed more, right? Another thing is how the thickness and width affect the compression on the belly. I thought at first that a wider bow with a thinner thickness would be overtaken by a strong backing first. But then after thinking about it, doesn't a unbacked bow fail because the compression of the belly is too much for the back to take? Wouldn't stretching the load by widening the bow and reducing belly thickness, in effect reduce the amount of compression going on? I know wider limbs with thinner bellys bend more because there is less compression pushing against the back. There for, reducing the chance for compression failure? Of course, this is providing perfect tiller, as it still makes sence of one hand that if a bow is wider and thinner AND has a tiller flaw, a backing which causes more stress on the belly would stress the flawed area and brake it before a thicker bow would brake, right? I never fail to confuse myself. Would it be the other way around, if a bow was thicker in belly the backing would be less likely overpower the belly? Like when a bows belly is trapped because of it being compression weak?
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline Badger

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Re: When backing overpowers a bows belly, what does it looks like? ...
« Reply #4 on: November 03, 2010, 04:35:04 pm »
  Most all woods are stronger in tension than compression. A good amount of failures are due to some kind of defect in the back not always visible. Some experts have said that setting aside defects most all failures are in compression. I never could really look at the wood and say for sure if it was compression or tension by the break. Guess I never really studies it than much. Something I have seen many many times and it still kind of puzzles me is how many bows I have seen break that were highly stressed but shown no signs of set yet, just suddenly explode. I kind of know when it is going to happen but don't know what it is tipping me off besides instinct. Wood that is very dry gets stronger in compression and weaker in tension, this can cause a lot of failures. Not much help with this post, just observations. Steve