Umnumzaan Blade Play

S

spectre3

Joined
Jan 30, 2009
Messages
10
After tuning the pivot on my Umnum to reliably open all the way with a moderate push of the thumb( no wrist flicking etc), I've noticed that when I open the knife slowly there's just a little side to side blade play and I can push the lock bar over to about 60%. With this method it locks up on it's own at about 30%. When I flick the blade out( no wrist flick just thumb tension overcoming the detent), it locks up tightly with no side to side blade play at about 60% and the lock can't be pushed over. No matter how I open it there's also just the SLIGHTEST amount of up and down play. Should I take everything apart, re-loctite and readjust to have slightly more pivot tension or is this something I need to send to CRK?
 
I would take it apart and reassemble before sending it in. It's possible everything just isn't seated correctly. If this doesn't fix the issue, I would send it it. Zaans are rock solid so it's rare you will ever have blade play issues with one.

In terms of the slight up and down play, how old are the o-rings? It's possible they could be worn or have a flat spot where they hit the frame?
 
Can you define "tuning the pivot"? Was that simply adjusting the pivot screw?

Are you feeling the compression of the O-rings and translating that into blade play? Prior to lock-up there will always be some play because only one of the three lock points are "in-play" so to speak.
 
Take it apart, clean it, put new grease on it. This time though, apply grease sparingly, like very little.
I’ve had issues with using too much grease and experience that slight side to side play.
Don’t have a clue what you mean by up and down play. Is this play happening after it’s locked, or does it feel loose and not hydraulic opening the blade ? It may be that the pivot is too loose ???
 
Knife was made in 17. O-rings look good and have no flat spots. All references to blade play refer to when blade is locked open. Up and down meaning up towards the spine and down towards the lockbar. Side to side being towards either scale. Tuning the pivot just means adjusting the pivot screw. It may be compression of o-rings causing the play, but I feel like it shouldn't be an issue given the cost of the knife and "legendary CRK tolerances". I can see the movement. I'm going to take it apart, use less grease, and re-assemble and see if that does it. If not it's going to CRK. I feel like no matter how I open the knife the lockup should be the same with no play in any direction.
 
CRKs should haven't any kind of play, especially the up/down lock rock. I'd do what was recommended above and take it apart, regrease and put it back together. If the symptoms persist, then I'd send it back in to the mothership.
 
spectre3 said:
Knife was made in 17. O-rings look good and have no flat spots. All references to blade play refer to when blade is locked open. Up and down meaning up towards the spine and down towards the lockbar. Side to side being towards either scale. Tuning the pivot just means adjusting the pivot screw. It may be compression of o-rings causing the play, but I feel like it shouldn't be an issue given the cost of the knife and "legendary CRK tolerances". I can see the movement. I'm going to take it apart, use less grease, and re-assemble and see if that does it. If not it's going to CRK. I feel like no matter how I open the knife the lockup should be the same with no play in any direction.
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Side to side play should definitely not be there. For the up and down play: are you grabbing the tip and firmly wiggling up and down? If you do that you will force movement in the lock up. All 3 of the zaans I’ve owned did this and I don’t consider that blade play. However if you are gently wiggling up and down and there is movement than yes you have a problem.
 
The up and down play could be from the ceramic ball moving around a bit on the tang. Especially if it's new.
 
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