Broken SDS drill bit

Bob Engelhardt fired this volley in news: snipped-for-privacy@news1.newsguy.com:

First of all, the shank didn't break, the web did.

Second, it's been broken for a long time, and just finally failed.

Lloyd

Can anybody (Ed ... ?) see anything in the linked photo that might say something about the break? I left the photo big (2000 x 1200) to keep details.

It's the shank of an SDS max drill bit. Carbide tipped, so I thought the shank would be mild. Yet, to me, the break looks like that of hard steel.

Does the varying color mean anything?

Thanks, Bob

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That's interesting. Fracture mechanics is something I haven't dealt with in

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.

OK. I was thinking of "shank" as everything behind the tip. Not anymore.

Meaning that there was a defect in it?

Thanks, Bob

Thanks, that helps. Bob

Bob Engelhardt fired this volley in news: snipped-for-privacy@news1.newsguy.com:

Perhaps, or perhaps it had been flexed or twisted to the point of cracking in some prior use. But it wasn't during _this_ use.

Lloyd

Wait, that wasn't the web you meant? Sorry!

Cute, but no Brownie Points. And speaking of points, have you downloaded your Algore Smog credits yet?