Interesting edge failure

unit

unit

Joined
Nov 22, 2009
Messages
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OK, first off...lets not discuss the quality of the knife or what should or should not have happened. I do not care, I am simply sharing some photos of a knife/edge failure like none I have ever seen before (and I have seen a few knives in my day).

A co-worker "loaned this knife to a friend who was preparing wood for a fire". What you can hopefully see in the images below (just beyond the serrations) are two bevels that are mostly intact and a separation that occurs very near the edge apex. This separation has apparently allowed wood to enter the blade and split it apart. The blade actually appears to be split by the wood instead of the other way around.

On with the images...







edit to add quick video (hopefully for better visualization).

[video=youtube;z7LdEu6qcRw]http://www.youtube.com/watch?v=z7LdEu6qcRw[/video][/QUOTE]
 
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Wow, thats the strangest thing I've ever seen! Loking forward what other people from the forum have to say about it!
 
Haha! Just commented on this video. I guessed wrong, partly.

That is the weirdest thing I've ever seen a knife do. What steel is it? CCC?
 
i would question the heat treat but i have seen some strange things when sharpening knives before. one thing i seen a few months ago were air pockets in a blade right along the edge. maybe the same thing was wrong with that blade allowing the wood to split the steel. it would be interesting to see what the blade looks like with the wood removed.
 
Oh wow, that third pic made my jaw drop. You're right, it certainly is interesting. I'm anxious to see if anyone else has ever seen anything like it. Thanks for sharing, I'm shocked and fascinated.
 
You mentioned in your comments in the vid that the owner is seeking warranty replacement. It would be nice to know what comes of that.
 
Thats a delamination in the blade, from all appearances. When the steel for the blade was made, it was a small gas bubble or blow hole. When the steel was hot rolled, it was mashed flat, but didn't weld together for whatever reason. It's interesting that it showed up in the very middle and not to one side, but sometimes that happens. There were some Scrap Yard knife pics floating around with the same "feature" that split the same way when chopping some wood. It wasn't in the middle, but was still in the edge bevel. It's a problem with the manufacturing of the steel and should definately be covered by warranty. It's the type of thing that were it a brake pad or axle, there would be a recall.
 
1st for me but I agree with the delamitation theory. I believe that flaw was in the steel before the blade was made. My knowledge is limited, but I spent a few years working in QC for Gates where we spun steel under high pressure (cold process), to make car pulleys. In order to visually analyze we would cut, polish etch and magnify and look for that exact failure.
 
nice, the splits I've seen posted popped up right out of the quench, this one took a while to find, lol
 
singularity35 said:
You mentioned in your comments in the vid that the owner is seeking warranty replacement. It would be nice to know what comes of that.
Click to expand...

I will let you know. I already told the guy that if they do not take care of him, I will (if he gives me that ruined knife). He was hoping it could be repaired, I told him I would not even try (the separation extends quite a ways into the blade).

It will be nice to hopefully convert another knife user into a knife appreciator.
 
154CM had air pockets when it had some production issues, this might be the case here with this type of steel as well, it is my best guess anyway.
 
I agree with the air pocket theory. The way the pocket was generated is perhaps debatable (I do not even know what sort of steel this is beyond "stainless" nor can I be very sure of the processes by which this blade was formed). For all I know the stock was punched/cut from the edge of an ingot that had an edge that rolled over and partially annealed itself during processing.

I just wanted to share what I thought was an interesting failure. Judging from the responses, a few others have not seen failures like this either.

I do appreciate the insight shared thus far. I enjoy learning from others that have seen or heard about stuff like this...keep it coming!
 
unit said:
I will let you know. I already told the guy that if they do not take care of him, I will (if he gives me that ruined knife). He was hoping it could be repaired, I told him I would not even try (the separation extends quite a ways into the blade).

It will be nice to hopefully convert another knife user into a knife appreciator.
Click to expand...

Thanks.
 
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