Confusing sideways bend

[WillS]

I've been round the ringer with this on Facebook for days and got nowhere, so hoping someone here can help!

I have a batch of English yew that so far has broken 4 times in a row, and every time the stave has done this before exploding.

This is a dead straight, well seasoned stave that in the photo is pulling to brace height. The arrows show where its bending, and I can't for the life of me work out why, or what the solution is.



Thoughts, opinions and ideas needed before I break five in a row!

[PatM]

Too narrow relative to depth?

[Dances with squirrels]

Is it a one piece stave or spliced sister billets?

[WillS]

One piece.  It was roughly 33mm x 25mm in the area that's bending sideways the most.

I say was, because its just blown up.  5 in a row from the same tree.  Perhaps it's fate.

[PatM]

I think you're just seeing what people see when they make  narrow reflexed laminated bow that wants to bend sideways and reverse string itself.
 It's just following the path of least resistance.

[WillS]

It wouldn't normally be a problem, and had it been a one-off I'd have ignored it.  The trouble is that every single one of the staves from this particular tree have done it, which I find pretty unusual.  The wood also clearly can't cope with any sideways bend, as this one blew up just a bit past brace height at 50lb.  I've made bows before well into the 100lb range that do this to a lesser extent that are fine.

Very odd!  And frustrating.

[Ryan C]

Split or sawn stave

[DC]

Do you have a picture of the break? Did it break across the back or on the side(sorta)

[Badger]

  My first guess is that it is too narrow in relation to the density of the wood, can you weigh the broken pieces?

[PatM]

   So you just kept doing the same thing five times in a row?

[WillS]

   So you just kept doing the same thing five times in a row?

No, I'm not crazy 

I've been trying different things each time.  Heating it out, twisting it out, removing wood from the opposite side and so on. 

[WillS]

Split or sawn stave

Split.

[WillS]

Do you have a picture of the break? Did it break across the back or on the side(sorta)

[WillS]

  My first guess is that it is too narrow in relation to the density of the wood, can you weigh the broken pieces?

936g for both pieces together.

[Marc St Louis]

Could be the working properties of the wood perpendicular to the grain is poor.  You should try a flatter profile