Blade Sheared into two pieces from Fall

[linuxology]

A blade fell off my stand up desk ~ 3-4 feet onto a wood floor/w a wood subfloor. I heard a sound that sounded like shattered glass and when I looked the blade was sheared into two pieces. I don't recall the steel type, but think it's 154, though this could be incorrect. I know it's a stainless blade.

I am looking for knowledge sharing because I was a bit surprised to see the knife was broken from a fall. I have dropped blades before and this has never happened. I'm not looking to blame anyone but myself in this. I'm not upset and crap happens. I have dropped multiple knives and had a knife go through my shoe before. This is the first time a knife has sheared on me. Definitely sucks because this blade was a hell of a slicer.

To my recollection, Erik Loreno uses Peters Heat treat for his blades. Please don't flame me because this is not a smear campaign and losing a blade is tough enough. This post is intended to be a place for myself and others to learn as to why this may have happened. Could this be a defect in the heat treat, is it more along the lines of the toughness of the blade, or just potentially the way that it fell? I did not see it hit the floor, so can't explain the way it hit. It seems it would have stuck in the floor if tip down, but unsure.

 

[DMG]

It looks like an inclusion or bubble in the steel near the spine. A knife shouldn’t break like that. I would talk the maker about warranty.

 

[jaypopsti]

Can you post a pic where the broken part of the blade is in focus? Head on so the grain structure is visible?

 

[linuxology]

Can you post a pic where the broken part of the blade is in focus? Head on so the grain structure is visible?

 

[jlauffer]

Certainly not an expert, but from what I've seen on FiF, that dark area suggests there was a defect in the blade.

 

[jaypopsti]

Certainly not an expert, but from what I've seen on FiF, that dark area suggests there was a defect in the blade.

This

 

[not2sharp]

You are very lucky it didn't break in use, it could have caused some serious injuries.

n2s

 

[evilgreg]

I'm just a random Internet dummy but that looks like a manufacturing defect to me. By comparison, when you look at knives snapped in destruction tests the steel usually has a fairly uniform internal appearance along the break line.

 

[Danke42]

Your hands are in excellent focus but the knife and any hints about it's grain structure remain as fuzzy as a Sasquatch.

Fine a way to just have the knife in the image and shoot with a dedicated camera and macro lens/setting.

 

[OrangeBlueOrangeBlue]

Certainly not an expert, but from what I've seen on FiF, that dark area suggests there was a defect in the blade.

I agree. There definitely seems to be a dark spot with a different grain structure at the spine. Was the dark spot on the spine always there?

 

[unwisefool]

Be easier to tell if the pictures of the knife were actually in focus

 

[linuxology]

Be easier to tell if the pictures of the knife were actually in focus

Your hands are in excellent focus but the knife and any hints about it's grain structure remain as fuzzy as a Sasquatch.

Fine a way to just have the knife in the image and shoot with a dedicated camera and macro lens/setting.

Are these better?

 

[WValtakis]

Yes, there was definitely a crack before the break evidenced by the rusty patch at the spine.

 

[220-9er]

The dark area appears to show beach marks that indicate fatigue failure from repeated stress in a particular direction.
This was a breakage that was already in the works, not just caused by a one time event (the drop).

 

[BluntCut MetalWorks]

My guess from looking at fractured...

Knife knocked off desk, landed on the side/flat handle at around 15-30º tail to tip. This tail to tip whip generated lateral shock wave, which initiated/originated a shear/tear point at edge then propagated toward spine.

Break type is mostly intergranular (brittle reflective surface layer - most likely be Cr deposition in grain boundary). Darker surface in spine area looks like transgranular fractured(more ductile). Also fractured surface near spine look fresh rather than long existing progressing crack originated from spine downward.

 

[Danke42]

That ping sound is never a good sign.

 

[unwisefool]

I'd contact the guy who made it and see if you can work something out.

 

[Bigfattyt]

Micro crack where you see the rust/discoloration is where the crack/flaw was. It has been there, likely since it was made.

 

[linuxology]

I'd contact the guy who made it and see if you can work something out.

I have emailed the maker based on the responses and the insights shared from a personal friend who is also a knife maker that is very skilled and knowledgeable in H/T.

 

[Twindog]

I was trying to figure out those lines, like tree rings. 220-9er may be right. I had never heard of beach marks, but it's a real thing.

Here's a photo I found:

And here's a shot of an 8670 blade that I broke -- no beach marks, just a big crack.