Author Topic: BL compression fractures help  (Read 3816 times)

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Offline Lee Lobbestael

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Re: BL compression fractures help
« Reply #15 on: December 13, 2012, 12:25:09 am »
Ok thanks guys. I will finish it and then go back to ol faithful (hickory) got lots in my woods! btw anyone want two nice BL staves? Trade ya for an osage! :laugh:

Offline Jim Davis

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Re: BL compression fractures help
« Reply #16 on: December 13, 2012, 12:38:10 am »
I've made a lot of locust bows. I like the wood. It seems to me that your bow just isn't wide enough for the weight, meaning, it would have been a little thinner if it were wider and still pulled the same weight.

My first locust was made from a tree about 3" in diameter under the bark. I decrowned the sapwood and left it on. Limbs were about 1-1/2 wide at the fades, straight taper to 3/8" tips, 66" ntn. The bow had nearly 5" of reflex when first finished. Kept about 3" after shooting.

That bow had a spider web of chrysals from end to end. I shot it for a year or so and it kept that reflex. Shot great. It would still be going If I had not accidentally overdrawn it.

I think you have a shooter and I would just make the next one a little wider for that weight.

Jim Davis
Jim Davis

Kentucky--formerly Maine

Offline Lee Lobbestael

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Re: BL compression fractures help
« Reply #17 on: December 13, 2012, 07:56:03 am »
Thanks Jim! I think a lot of people mis read my post. I said I made the limbs 1 3/4" wide. Thats wide enough isn't it?

blackhawk

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Re: BL compression fractures help
« Reply #18 on: December 13, 2012, 08:24:03 am »
You said "almost uniformally" along the limbs...what do you mean almost? Is there a break in between some of them? And how long(measured) is the section of frets? 1 3/4" might not be wide enough if you tillered your bend into too short of a concentrated area or areas. Again,id need to see the unbraced,and full draw pics to say for sure what went wrong.

Offline PEARL DRUMS

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Re: BL compression fractures help
« Reply #19 on: December 13, 2012, 08:25:18 am »
Lee your on the right track with osage. Get some and be happy.
Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.

Offline Jim Davis

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Re: BL compression fractures help
« Reply #20 on: December 13, 2012, 11:23:36 am »
Thanks Jim! I think a lot of people mis read my post. [some definitely did, I didn't.] I said I made the limbs 1 3/4" wide. Thats wide enough isn't it?

With locust, I try to make my pyramid limbs 2" or more wide at the fades. And, my bows turn out around 45#. But  they have no chrysals, even after several years of use. I do think your belly wood was just under too much strain.

I say was because now that the surface has fretted, the strain is being carried below the surface, essentially behaving as if it were thinner.

I'm guessing that when you finished tillering, the bow was a little heavier than it is now. The good side is, the bow will sustain the weight it is now, and as i opined earlier, it will be a shooter.

Just go  wider next time and try for the same weight, or a little less than this one is.

One other thing that doesn't get considered with ring porous woods is  that a tapered belly requires more of the compression forces to be carried by spring wood where a growth ring feathers out. A pyramid bow is one thickness throughout and growth rings  on the belly run from fade to tip, resulting in a uniform consistency everywhere on both belly and back.

That's why I make only pyramid bows.

Jim  Davis
Jim Davis

Kentucky--formerly Maine

Offline Lee Lobbestael

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Re: BL compression fractures help
« Reply #21 on: December 13, 2012, 05:42:48 pm »
That is a very good point about pyramid bows Jim. I have never tried one. Maybe that is what I will try next.

Offline Lee Lobbestael

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Re: BL compression fractures help
« Reply #22 on: December 13, 2012, 09:18:07 pm »
woud it be worth trying to heat treat the belly really good and then dropping the poundage as well?

Offline Jim Davis

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Re: BL compression fractures help
« Reply #23 on: December 13, 2012, 09:41:37 pm »
Lee, I think the  poundage has dropped by itself from what you had it tillered at. I think it's time to just shoot the bow and enjoy it.
Can't really see heat treating at this point. But, it's your bow. If you want to see what happens, go for it.

Jim
Jim Davis

Kentucky--formerly Maine

Offline Lee Lobbestael

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Re: BL compression fractures help
« Reply #24 on: December 13, 2012, 09:59:58 pm »
I think  I will just finish er up an shoot it.