Umnumzaan blade moving slightly when closed

S

Shrykos

Joined
May 8, 2016
Messages
58
A week ago, I purchased a used (but not abused) Umnumzaan off of one of the members here, and I've been opening and closing out of sheer pleasure. However, I noticed yesterday that when the blade is in the closed position, I can press down lightly, and the blade moves down ever so slightly (maybe a mm?). I also felt that the lockbar would move slightly in tandem with the pressed blade. What could cause this? A worn out ceramic ball? Any help would be appreciated, thanks.
 
It happens when the detent ball and the hole are not aligned well. Sounds like the ball drops into the hole completely stopping the blade before the blade hits the stop pin. It happens in some of my factory framelock knives.

But it is surprising to have that issue with Umnumzaan or CRK knives. The detent ball placement on my Umnumzaan and Sebenza is near perfect.
 
Could the orings affect this? I'm not sure that the ones on mine are the original, since they are red instead of black.
 
Are the O rings in good shape? Doubtful the ceramic ball is worn out or oriented incorrectly.

ETA: No they are not original if they're red. Order some from CRK (they're cheap) and see if that fixes the issue.
 
I guess it is possible that, if the o-rings are too thick and thicker than the original, the blade stops prematurely. With mine, the o-rings do not seem to engage with the handle when closed, as it makes a click sound upon closing.

With that said, can you take off the o-rings and see what happens?
 
I just took them off. You were right, the o-rings were too thick. The blade doesn't move anymore now. Thanks for your help! By the way, do you know where I can get some o-rings that match the dimensions of the Umnumzaan? The seller sent some extra o-rings, but I suspect that they're the same as the bad ones.
 
As far as I can tell the most likely reason in wrong size O-rings. If they are thicker/larger in diameter it will prevent the detent ball from fully resting in the detent hole on blade.

To make sure that is the issue remove the O-rings and try same thing. See if it happens. It should not since the studs will hit the frame without th ring cushing.

If that works replace the O-rings but if thats not the issue might wanna call CRK see what they have to say.
 
U can also get at like a hardware store HomeDepot/Lowe’s the size OO rings it will be in the plumbing station. Its like a $1.50 for 8 or so rings.
 
Ah shit guys. I found something else. The blade, without the o-rings, sits solid when it's closed. But when I try opening it, the blade moves about 2mm before I hit pressure (where the detent is). I can also feel the lockbar moving with it too. I think the ceramic ball might be worn out, but I'm not sure. This is different from my problem above in that there is no downward play when it's closed, but there is upward play. Any additional help would be greatly appreciated!
 
I hihly doubt the ceramic is worn out. Its the hardest part in entire knife.

I recommend taking it apart cleaning and reassemble with correct O rings then try it again
 
Yeah I thought mine were weird because they looked sloppy and of poor quality. CRKs are known for their crisp, clean machining right?

Edit: any advice on what to do?
 
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