Brittle Old Ka-Bar

Cypress

Cypress

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Jun 22, 2009
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I sharpened a Ka-Bar for a friend of mine lately and couldn't seem to get the tip sharp. Turns out, the tip just kept breaking off on the plate as I was working on it. The swedge grinds on the knife were WAY out of whack which took a lot of patience to work with. This knife is a NORD-4723 model, so it's probably got a late 1943/early 1944 production date.

I was going for a 21DPS edge on the main and 24DPS for the sharpened swedge, so I don't think the angles are too acute. I wasn't rolling the plate off of the end of the blade (to my knowledge).

What would cause 0.5-1mm of tip to just continuously break off under almost no force? Does anyone have an idea of what steel was used in these knives?

The nice thing about how brittle it seems to be is that the burr goes away faster than it forms :D
 
Might be heat-damaged at the tip. If the knife had been sharpened or ground on a powered grinder at some time in it's history, it might've been overheated. Knife tips are a common area for that to happen. If it did happen as such, it might take some metal removal at the tip to get back into healthy & strong steel.
 
That nord number is for the fiber sheath. Doesn’t mean anything about the knife.

sounds like it was heat damaged or just not made right in the first place.

if you post pictures of the knife we can give you a better idea of when it was made.
 
Also, during WWII the Army needed a lot of knives, and they were made by various machine shops and farm-implement dealers, often with secondhand steel that had various flaws and inclusions. QC was not the first concern.
 
My apologies, but I don't know any of the Ka-Bar model numbers.

I believe 1095 is what the Mil Spec's called for, if it is the "fighting knife".

So far as I know, the single and multi-blade folding knives they used to make, such as the Barlow and "Texas Toothpick" among others, also used 1095.

My guess is the same as others have mentioned. The tip was probably over-heated sometime during its history.
It will probably sharpen out ... eventually. You might lose .25 to .375 inch of the blade before it does. :(
 
Occurs to me also, it seems like old military or camp knives like these, especially those with very long histories, might've been used or abused in all sorts of ways. People use them to hold food over campfires or otherwise poke & prod at wood in fires, or heating the tips and using them to sear/burn/melt other things. All kinds of ways a knife like this could get heat damage at the tip. I'd still lean toward damage caused by powered grinding, as that's very common, even from the factory at times. Nevertheless, the 'fix' for it is always about grinding enough of the damaged steel off and resetting the edge. Sometimes that takes a lot of time and patience.
 
eveled said:
That nord number is for the fiber sheath. Doesn’t mean anything about the knife.

sounds like it was heat damaged or just not made right in the first place.

if you post pictures of the knife we can give you a better idea of when it was made.
Click to expand...

It's a USN MK II Ka-Bar with no marks on the guard and supplied with the sheath I described (NORD-4723 B.M. co vP). I did a decent bit of research on the knife/sheath before making this thread. If you know more about Ka-Bars than several different historical sites do, feel free to dump your knowledge in this thread, but it's not terribly on topic. I honestly don't care when the knife was made (not my knife, it'll probably get used as a screwdriver/prybar in the hands of the current owner). I have already given the knife back, so no pics.
 
Trying to help figure it out for you. I never said I had more knowledge than anyone. You were the one who used the model number of a sheath to figure out the date on a knife. When and who made it might give a clue to it’s brittleness. It might not even be war time. No need to be insulting or condescending. Only one person dumping anything in this thread.

I’m putting you on ignore just to make absolutely certain I never try to help you again. Good day.
 
Cypress said:
It's a USN MK II Ka-Bar with no marks on the guard and supplied with the sheath I described (NORD-4723 B.M. co vP). I did a decent bit of research on the knife/sheath before making this thread. If you know more about Ka-Bars than several different historical sites do, feel free to dump your knowledge in this thread, but it's not terribly on topic. I honestly don't care when the knife was made (not my knife, it'll probably get used as a screwdriver/prybar in the hands of the current owner). I have already given the knife back, so no pics.
Click to expand...

Question: No marks on the blade or guard? So how do you know it's a USN MK II? Any pictures?
 
Marks on the blade were USN MK2. No marks on the guard. As stated, no pics.
 
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