Author Topic: Post mortem/critique please  (Read 3302 times)

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Offline DC

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Post mortem/critique please
« on: April 27, 2015, 01:16:23 pm »
This was my favorite bow up until a couple of days ago. I made a new string and it was too short. The brace height went up to 8+" from the normal 6" and for some dumb reason I pulled on it. Momentary brain dead I guess. Anyway, I want to make another much like it so I thought maybe you guys could look and see if you can see areas that need improvement. It's an Ocean Spray R/D 62" NTN following the curves. 39# at 28". 1 1/2" wide at the fades tapering evenly to 1" about 7" from the tip and then down to 1/2" tips. It broke 11" from the center on the bottom limb. It looks like there is two very very small pins there but I think by that point it had to find a weak spot somewhere. I tried to take some pictures of the break but it doesn't show very well. It's an "H" shaped break right on the crown,1/2" wide and 6" long. I would think it is a very typical tension break. Here's the pictures I have. I can chop it into chunks if it will help.It broke where the red arrow is.

Offline DC

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Re: Post mortem/critique please
« Reply #1 on: April 27, 2015, 01:18:03 pm »
And full draw showing where it broke

Offline Pat B

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Re: Post mortem/critique please
« Reply #2 on: April 27, 2015, 01:25:44 pm »
It actually looks flat where the red arrow is. How does the back look otherwise?
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline DC

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Re: Post mortem/critique please
« Reply #3 on: April 27, 2015, 01:33:34 pm »
I'm not sure what you're looking for but the bottom limb is very clean, nothing over a 32nd of an inch. There is a typical OS lump halfway between the break and the handle. Can I try to take a pic of something for you?

Offline sieddy

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Re: Post mortem/critique please
« Reply #4 on: April 27, 2015, 01:54:45 pm »
That looks like it was a sweet bow man. Oh well I'm sure your next will be even better!  :D
"No man ever broke his bow but another man found a use for the string" Irish proverb

Offline Blaflair2

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Re: Post mortem/critique please
« Reply #5 on: April 27, 2015, 02:49:02 pm »
I thought same as pat
Nothing ventured nothing gained

Offline PEARL DRUMS

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Re: Post mortem/critique please
« Reply #6 on: April 27, 2015, 03:01:56 pm »
Your brace height increase isn't the culprit, if that helps you rest at all.
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 DC

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Re: Post mortem/critique please
« Reply #7 on: April 27, 2015, 03:33:57 pm »
Heck of a coincidence then.

Offline Badger

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Re: Post mortem/critique please
« Reply #8 on: April 27, 2015, 03:55:09 pm »
  A high brace height can change your tiller shape at brace, if the area that broke was starting to bend more at brace it would continue as you drew it. I still wouldn't say the high brace was the culprit but it likley exagerated a slight weak spot you allready had. +

Offline bow101

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Re: Post mortem/critique please
« Reply #9 on: April 27, 2015, 03:56:43 pm »
Wood is wood it does what it wants.  You could have a thousand shots thru a bow and one day you go out and shoot it first thing and it breaks.  Breaks happen. Move on to the next project.
"The privilege of a lifetime is being who you are."  Joseph Campbell

Offline George Tsoukalas

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Re: Post mortem/critique please
« Reply #10 on: April 27, 2015, 04:02:42 pm »
Looks like there is a knot just above the break.
Did you leave the knot slightly wider and did you tiller that part slightly stiffer?
Jawge

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If you ain't breakin' you ain't makin!

Offline DC

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Re: Post mortem/critique please
« Reply #11 on: April 27, 2015, 04:25:01 pm »
Here's a pic between the break and the handle. You can see the OS lump. There is probably a knot inside that. It's a bit wider and about 1/8" thicker. It's 4 1/2" from the break. The break is marked in Sharpie.

Offline PatM

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Re: Post mortem/critique please
« Reply #12 on: April 27, 2015, 04:28:11 pm »
Saw the lump in half and see what's in there.

Offline DC

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Re: Post mortem/critique please
« Reply #13 on: April 27, 2015, 06:44:48 pm »
There was nothing but wood in there. I think there was a knot in the other half of the stave and this was just a swelling coming around. OS over reacts to knots and injuries and makes these ugly lumps. It makes it nice for us because there is lots of strength around them.
« Last Edit: April 27, 2015, 06:55:58 pm by DC »

Offline bentstick54

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Re: Post mortem/critique please
« Reply #14 on: April 27, 2015, 11:16:11 pm »
I'm with Jawge. It looks like a very small knot right about the break. My guess is the lump between the handle and the break caused a stiff spot that put more stress on the limb where the little knot is and finally caused the break. Just a guess though, as I am still a beginner and have only made 8 or 9 Osage pyramids to date.