So my daughter and I spent Saturday at a friends house making Osage longbows...it was our first time and it was terrific...
We roughed out two bows and at the end of a 12 hour day we had strings made and could shoot our bows...
Once we got home it was still light so we got some arrows and shot her bow for a few minutes...
Unbelievably quiet, and more powerful than I thought it would be....until the third shot when the lower limb let go and the bow blew half in two...
My question is...is this something that just happens once in a while or is there a way you can evaluate a stave so you can pick only the good ones...?
I'm not an immediate gratification person and neither is my daughter, but it really sucks to put that much work into your first bow and have it blow up on it's third arrow...
Wondering if it's worth it........
Unless you have some experience with osage it is easy to overlook a tiny snaky section in the grain on the side of a limb, cut your limb profile through the snake, produce a grain violation and have a potential failure waiting to happen.
A carefully laid out osage bow is very durable. Every time I thought the slight grain violation I had cut through on a limb wouldn't be a problem, I found out it was.
Your limb failure could have been from a bunch of different things, not seeing the damage it is hard to speculate, I suspect a grain violation.
Bad tillering, hingy limbs, failure at a knot or just a bad piece of osage are all possibilities.
would need to see the bow limb were it broke to guess what happened. I have had a couple blow up but it is usually do to a flaw in the grain. sometimes you might miss or hopefully ignore a pin knot in the wood grain and it sneaks up to bite you. My guess is the grain had a wiggle in it and it wasn't followed when laying out the bow.
So how do you follow a wiggle while cutting the limb form out on a bandsaw?
Seems like it'd be way too easy to cut what you think it perfect but actually be cutting through some important stuff that wiggled but you didnt know.....
Mark a centerline following the grain from tip to tip on your stave. Then you layout your limb width measurements off of that centerline. If youre having a hard time seeing the grain try adjusting your light source till it becomes easy to see. Heres an example :
(http://i1231.photobucket.com/albums/ee503/Jamey_Burkhart/AACD085D-7A65-4893-97A7-EC2DF939D18A-5016-00000D8606DAC329.jpg)
Ok...I think I see what you guys are talking about now....I was careful with the top but not concerned about the sides which is probly where we went wrong....we must have cut into the grain a little bit somewhere down the sides...
thanks for the help and experience guys...we're gonna try again and see how we do.
There's something real theraputic about all this...
When I lay out the top profile I take my stave out in the sunlight, put one end on the ground, tilt the stave at about a 45 degree angle to the ground and look down it with my face about a foot from the stave. I will have already have drawn a center line on the stave and laid out its basic width.
There will be white longitudinal lines that will stand out for the entire the length of the stave when you get the angle to the sunlight just right.
Here is what you will see, the camera went out of focus at the grain swirl around a knot but you get the idea of how the longitudinal lines run end to end on a stave.
(http://img.photobucket.com/albums/v181/ekrewson/grainswerlforlayout_zps02aacd7b.jpg) (http://smg.photobucket.com/user/ekrewson/media/grainswerlforlayout_zps02aacd7b.jpg.html)
I go down my width markings and follow any grain wiggle with a pencil. Wiggles are usually side to side on a stave, occasionally they will only show up on one side so follow them accordingly.
(http://img.photobucket.com/albums/v181/ekrewson/grainswirlpenciledin_zpsd499a602.jpg) (http://smg.photobucket.com/user/ekrewson/media/grainswirlpenciledin_zpsd499a602.jpg.html)
If you use a bandsaw it is best to only cut close to the wiggly lines, don't try to follow them. One mis-cut and you will ruin a stave. I did exactly that last week, I knew better....
Cut close to your line with your bandsaw and finish up with a rasp.
I would have to agree. natural light is the way to go. I dont always catch the meandering grain with the light in my garage. i should make a point to look at my layout in the sun before I start cutting. this is the problem with building bows in the wee hrs of the night.