I think I have a problem. . .

[kahunter]

Hi guys, I was wondering if some of you selfbow guru's could help me out.  I bought a selfbow from a guy locally and have really enjoyed it.
  However, when I strung it up the other day I noticed that something didn't look right.  It almost looks like the lower limb is giving way or something, but I don't have enough experience with selfbows to know what is going on.

The measurement from string to limb at mid-limb is about 7/8" difference.

Here are a couple pictures of the bow.  What do you think? Is it still safe to shoot?

 

 

[CardboardDuck]

How are you stringing it? Does it even back out with a couple of short draws?

[Razorbak]

its out tiller..make a gizmo and re tiller and a couple scrapes and limb excersize you will enjoy once again shooting that bow

[kahunter]

I've mostly used a stringer, but I did use the "step through" a couple of times.  Hope I didn't screw it up.

I tried drawing it a few times, but it didn't even out.

I don't see any signs of stress fractures.

You think it's just out of tiller?  I would need to scrape more off the top limb to even it out right?

[John Scifres]

I would go back to the bowyer for advice.  But yes, it has definitely sprung for some reason.  Might be fixable.  Might not.  Stepping through probably didn't cause it to go that bad unless you really did it badly.

[CardboardDuck]

The only reason I asked about the stringer is because the bow I made for my father in law did the same thing. I found out he bought a stringer for recurves and not the one I recommended. He was overstressing the lower limb when he strung it. I was able to even it out again.

[Bowjunkie]

Yes, some stringers can stress the lower limb quite a bit more than the top, as can the step thru and push-pull methods if you're not careful to do it just right. Some folks string their bows the other way... flip their bows around and slide the string up the bottom limb. I know folks who alternate every once in awhile, and folks who do it upside down every time.

[Bowjunkie]

You don't string walk when you shoot do you? Doing so can place a lot more stress on the lower limb than it was tillered for.

[Bowmonk]

A few probable causes...

1. shooting with excessive heel down hand position
2. excessive stress on the lower limb while stringing.
3. shorter lower limb... which in time results in set, but should result in weakness.
4. a weak spot in the wood that has finally given way to stress (check for chrysalling)
5. a bow stringer that uses the rubber grip pad to bend the limb vs using the end to end method.

-Russell

[Bowmonk]

Add to this... Humidity and standing a bow in the corner.

Or... it is also very possible that it was overdrawn beyond the point of original tiller. Since experienced bowyers are usually pretty careful about not taking a bend past the intended draw length and above the intended draw weight, it can have a bad result on the overdrawn bow.

When I was making bows for people more regularly... I finally adopted the idea that I would tiller a bow 2" past the requested/intended draw length, at 6 to 8 pound more than the intended/requested draw weight.

This somewhat safeguards a bow from being damaged even if your best friend picks it up and unwittingly overdraws the bow.

[kahunter]

I shoot 3 under, but don't string walk.  I can't imagine shooting 3 under would do that though.

I do use the stringer with the rubber block on one end.  I can see how that would stress one limb more than the other.

I'll have to see if I can get hold of the bowyer, or maybe use this as an excuse to start experimenting.  Eventually I want to make my own, but just don't have the time to devote to it right now.