When piking a bow that I made...

[knuklhed]

Should I start from ground zero on the tillering tree, with a long string? Or, since it had been to brace height and shot some before, skip to the new string length to check the tiller? And, out of curiousity, how much does tillering generally change when you change length, or doesn't it? For background, it was my second attempt at a tri lam, and came in really light. I had previously given up on it and hung it on the wall, but this afternoon, I had some time, saw it and said, what do I have to lose? Maybe it will be somewhat usable if I bring the weight up by shortening the darn thing. Or, it will wind up in the wood stove like number one.  Thanks for any opinions and help, Roger

[Pat B]

You should be able to pike the bow without retillering as long as both limb tips are cut the same. You'll only gain about 3# per inch of pike. If it's been sitting around for a while be sure to exercise it slowly out to full draw.
Don't forget the pics. 

[knuklhed]

Just got out to full draw, when I believe I found the elastic limit.... this will meet the same fate as my first attempt, making heat this winter    

[Pat B]

That break came along a grain line. See how short the break is? Breaks like this usually follow the grain whether it be lateral or radial grain. What is the backing material?

[Roy from Pa]

Yup, looks to be a 1/4 sawn belly lam and appears to be a dark spot inside the break area.

[knuklhed]

Here are a couple more pics of the break, I'd be interested in any more opinions as to why, and how to avoid it in the future. Pat, the backing was hickory, the core was elm, and the original belly was maple, then backed with a strip of osage when I realized the stack was too thin, and it was very light.

[Roy from Pa]

There is a dark spot in the Osage and the grain runs out to the side.

[attachment=1,msg2974608]

[attachment=2,msg2974608]

[Pat B]

You probably would have been better adding the osage to the belly and kept the hickory backing. Osage makes great belly wood because it is compression strong and hickory is tension strong so it makes a good backing. Hickory is actually my favorite bow backing wood because it is so strong in tension and nearly unbreakable. If hickory breaks across grain it has been infected by fungi. Otherwise it can almost be bent in half with possibly only slight splintering.
The steepness of the break tells me that was a grain run out back to belly of the osage and not necessarily side to side. If it had been on the belly it more than likely wouldn't have broken.

[mmattockx]

You probably would have been better adding the osage to the belly and kept the hickory backing.

+1, osage is an outstanding compression wood.


Mark

[knuklhed]

I probably didn't quite word that right. I did add the osage to the belly, on top of the maple.

[Pat B]

So, the belly failed?  It doesn't happen often but with that short of grain it's possible. Usually when a belly fails it is crushed. This looks sheared, like the grain slipped.
What does the back look like?

[knuklhed]

Pat, yes, the belly failed, through to the elm core that you can see torn along its grain. The back of the bow was still intact. That hickory is tough.

[OldRawhide42]

Does it matter which way the grain is on the hickory ??
 

[Pat B]

If it is good, sound hickory probably not. I bought hickory slats from a guy named Johnny from Louisiana years ago the had grain going every which of way and never had a back failure with that hickory. Biased or edge grain are probably the best.