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?

http://home.comcast.net/~bobengelhar...42_resized.jpg

Thanks,
Bob

Bob Engelhardt fired this volley in
:

http://home.comcast.net/~bobengelhar...42_resized.jpg

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

"Bob Engelhardt" wrote in message ...

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?

http://home.comcast.net/~bobengelhar...42_resized.jpg

Thanks,
Bob

=================================================

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.

--
Ed Huntress

On 7/12/2014 7:07 PM, Lloyd E. Sponenburgh wrote:
Bob Engelhardt fired this volley in
:

http://home.comcast.net/~bobengelhar...42_resized.jpg

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

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

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

Meaning that there was a defect in it?

Thanks,
Bob

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

Bob Engelhardt fired this volley in
:

Meaning that there was a defect in it?

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

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com writes:

Bob Engelhardt fired this volley in
:

http://home.comcast.net/~bobengelhar...42_resized.jpg

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

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

http://dilbert.com/strips/comic/2004-01-11/
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

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

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

http://dilbert.com/strips/comic/2004-01-11/

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

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On Tue, 15 Jul 2014 01:40:08 +0000 (UTC), David Lesher
wrote:



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

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

http://dilbert.com/strips/comic/2004-01-11/

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? http://freecarbonoffsets.com
They're Deeeeeeeeeeecarboniferous!

--
Liberalism is a pathology.