Question about Ceramic lock interface

A

Art Lewis

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Mar 17, 2009
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Does anyone have experience with the ceramic lock interface on the Inkosi under heavy use? What happens when the blade is subjected to hard axial loads? E.g. when the knife has jammed in a piece of wood and you want to get it free with up and down movements? Can it happen that the ceramic ball presses into the steel of the tang and leaves an imprint? Or rather does the lock fail?
Background: Our family camp knife is a large Inkosi and used by several people. The last time I examined it, I noticed a small dent on the tang right next to and at the end of the polished line that pressure-polished the ceramic ball into the steel. The dent looks like an imprint of the cramic ball. Now I ask the boys and myself: how does it get there? Or has it always been there as a feature? Sort of: Under heavy load the ceramic ball gets caught in the dent to prevent lock failure.
 
My small has always had the same dent. Seems to be normal but wouldn’t mind seeing what others say about it also.
 
Art Lewis said:
Can it happen that the ceramic ball presses into the steel of the tang and leaves an imprint? Or rather does the lock fail?
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I would expect to see the rear hinge fail first. If you hammer anything enough things will happen. It's all material at the end of the day. In the case of the knife, the tang is hardened but not as hard as the ceramic ball, so the tang will yield first.
 
Have you used a toothpick to see if it is an actual dent. I’ve got an Umnumzaan that looks like it’s dented, but when I did run a toothpick on it, it’s smooth.
 
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Ajack60 said:
Have you used a toothpick to see if it is an actual dent. I’ve got an Umnumzaan that looks like it’s dented, but when did run a toothpick on it, it’s smooth.
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I’ve done that same trick on an Inkosi. It started to develop some grab when releasing the lock so I was curious if the blade was wearing. It was smooth as can be
 
It actually is a dent. I can feel it using the tip of a toothpick. But under normal lockup it is not touched by the ceramic ball. The dent is a tad beside the polished line. Maybe one of the boys did a spine whack test?
 
I have one Umnumzaan with what you describe. It still works flawlessly. It doesn't catch or drag. It locks up perfectly and I have no worries about lock slip.

When I first noticed the little dimple I freaked out a bit and went on a web search. I don't remember exactly what Google-fu I used, but after seeing it sporadically in pictures I convinced myself that it’s something that happens with some knives, even in the absence of abuse.

FWIW, my other ‘Zaan doesn’t have the dimple. It works just as perfectly. ;)

All that said, I use every folder as if it were a slip joint because locks can and do fail.

There are better tools for log splitting.
 
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Here’s a pic of my tang. Weirdly, the little divot is just above the wear track.



And here it is at lockup. Very solid. No stick.

 
Thank you for the picture! The dent beside the trackline of the ceramic ball is exactly what I have on mine. Wonder why there is a second wear line near the glass breaker on yours. Does the Ti-bar touch the tang?
 
I always wondered if anyone has ever managed to loosen the ball in the lock bar? Seems unlikely though.
Art Lewis said:
Thank you for the picture! The dent beside the trackline of the ceramic ball is exactly what I have on mine. Wonder why there is a second wear line near the glass breaker on yours. Does the Ti-bar touch the tang?
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Possibly when your squeeze the knife hard?
 
4mer_FMF said:
Here’s a pic of my tang. Weirdly, the little divot is just above the wear track.



And here it is at lockup. Very solid. No stick.

Click to expand...

Something is off here with that second wear mark close to the glass breaker. First time ever I have seem such marks on the Zaan.

BellaBlades said:
I always wondered if anyone has ever managed to loosen the ball in the lock bar? Seems unlikely though.



Possibly when your squeeze the knife hard?
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Yes there was a case. But it was beaten to a pulp.
 
Art Lewis said:
Wonder why there is a second wear line near the glass breaker on yours.
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marthinus said:
Something is off here with that second wear mark close to the glass breaker. First time ever I have seem such marks o the Zaan.
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The second “wear mark” isn’t a wear mark at all. It’s just the spot where the squared margin of the tang transitions to the lock radius. The lighting & angle make it look a bit goofy.

I’m not sure I explained that well, but it’s ok. It’s supposed to be there. I promise. :)

 
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Thanks for clarifying.
If we find a third owner who´s knife has the dimpel/dent I´ll ask CRK. Maybe it arises during production or occurred on a certain batch.
 
I have a 2008 Umnumzaan and a Sebenza 25. Both have seen daily carry and hard use. No issues with the ceramic lock other than the fact it doesn’t have the pleasing “double-click” sound of the 21.
 
I know for awhile that some Inkosi's had a purposefully done track of sorts and under certain strains on the knife people would see another mark from flexing of the lockbar when releasing it in a non perpendicular path (not square to the pivot). as i understand it, it's a non issue.
 
Today I had a new Inkosi in my hands and lo and behold .... it has the same little dent. The two knives that I have been able to examine more closely so far have all been more recent (December 2019 and January 2020). In my opinion, it has something to do with manufacturing. In any case, it has no effect on the smooth mechanism.
 
4mer_FMF said:
The second “wear mark” isn’t a wear mark at all. It’s just the spot where the squared margin of the tang transitions to the lock radius. The lighting & angle make it look a bit goofy.

I’m not sure I explained that well, but it’s ok. It’s supposed to be there. I promise. :)

Click to expand...
Thanks. Never noticed that before :)
 
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