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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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Broken SDS drill bit
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 |
#2
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Broken SDS drill bit
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 |
#3
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Broken SDS drill bit
"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 |
#4
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Broken SDS drill bit
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 |
#5
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Broken SDS drill bit
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 |
#6
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Broken SDS drill bit
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 |
#7
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Broken SDS drill bit
"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 |
#8
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Broken SDS drill bit
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 |
#9
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Broken SDS drill bit
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. |
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