On 7/12/2014 7:18 PM, Ed Huntress wrote:
That's interesting. Fracture mechanics is something I haven't dealt with
in 20 years, and I never could say anything conclusive about fractures,
but it looks like some kind of shear fracture. In general, the darker
area in one of these fractures indicates fatigue, and the brighter areas
indicate brittle fracture.

It doesn't mean the metal was brittle. If it really was fatigue that
started it, the rest just shows where the remaining metal was overloaded.

I doubt if the shank is anything less than a good tool steel. Mild steel
wouldn't take the pounding. Beyond that, I don't know.


Thanks, that helps. Bob