Lockup problem with Zaan

BilboBaggins

BilboBaggins

Joined
Feb 14, 2016
Messages
1,692
So I'm having problems with the lockup on my umnumzaan. Unless I make sure to really give it some force when opening, the lock can become disengaged with only minor pressure from on top of the blade. It doesn't happen every time, but it's got me seriously worried about my fingers and the integrity of the lockup. Any thoughts?
 
I would guess a lint build up. My Umnumzaan's have earlier lock up than my 25's. I've even noticed that too much grease on the washers will push out and get on the ceramic ball.
 
It was a good thought and it was slightly gunky in there, but the problem persists after cleaning and reassembly. :mad:
 
Honestly, the ceramic ball is the only thing that's ever kept me away from the Zaan. I think it's one of the best looking folders i've ever seen, but i stick with my large 21's, as innovative and nice as the ceramic ball lock face is, it simply doesn't have the contact surface are of the 21's normal lock bar. Don't feel like i could trust it as much as i do the standard lockup. Such a nice knife tho.
 
Bilbo, how far is the lock bar traveling/engaging on your "usual" opening? Could you post a pic? It *may* have to do with the O-rings.

Going from old O-rings to new changed the lockup of my 'Zaan, pretty significantly. I keep procrastinating ordering the Polyurethane replacements from CRK, and have been using #60 Buna's. I tried new Buna's from two suppliers out of curiosity, and the thickness or o.d. must be slightly different between manufacturers, because lockup varied subtly between those as well.

I also get a deeper lockup with a hard opening or with tough/heavy slicing. I've attributed it (in part) to the Buna being a bit softer than PU, but that's just conjecture (until I order PU replacements). Mine hasn't locked up so early as to make me worry, though. If I had it with me tonight, I'd shoot some pics.

Hope you get it worked out. The 'Zaan is phenomenal.
 
I was under the impression that the O- rings didnt change and or had no effect on lock up...read and watched a couple of reviews addressing this..actually saw lock up w/ and w/ out the O-rings in place...lock up looked the same.

Seems like they would effect...I'm a new owner of an Umnumzaan..haven't removed or replace O rings as yet...No ill lock up issue at all thus far. I do notice that I can squeeze slightly more travel...but that would be with most frame/liner locks that aren't flicked or slammed open initially.
 
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The o-rings work as a sound dampener and do not have any effect on lockup percentage. If the o-rings are removed, lockup will remain the same percentage as when new o-rings are used. The thumb studs have a groove milled into them for the o-ring to be captured in, and when the blade is opened, the edge of the stud contacts the frame and stops the blade opening, NOT the orings.
 
Did you purchase the knife new? Some people have been known to adjust the lock bar so it takes less pressure to disengage. If I recall correctly that is part of the reason Chris added the over-travel stop. I have several Umnumzaan's and they all have about the same amount of force to disengage and I'd consider it moderate force. If the lock bar was incorrectly adjusted it may be prone to slip release. The ball should rest at 50% or more on the lock face.
 
Well, perhaps my experience is due to using hardware store O-rings. To clarify, the "final" end point of lockup hasn't changed--at all. Perhaps I could have been more clear in post #9.
 
Perhaps?? The lockbar isn't set to move far enough to the right???
Put the knife together without the blade, see how far the lockbar goes over to the other side. Could be, not enough pressure on the ramp.
It should go over to nearly touching the other slab.

Just a thought.
 
4mer_FMF said:
Bilbo, how far is the lock bar traveling/engaging on your "usual" opening? Could you post a pic? It *may* have to do with the O-rings.

Going from old O-rings to new changed the lockup of my 'Zaan, pretty significantly. I keep procrastinating ordering the Polyurethane replacements from CRK, and have been using #60 Buna's. I tried new Buna's from two suppliers out of curiosity, and the thickness or o.d. must be slightly different between manufacturers, because lockup varied subtly between those as well.

I also get a deeper lockup with a hard opening or with tough/heavy slicing. I've attributed it (in part) to the Buna being a bit softer than PU, but that's just conjecture (until I order PU replacements). Mine hasn't locked up so early as to make me worry, though. If I had it with me tonight, I'd shoot some pics.

Hope you get it worked out. The 'Zaan is phenomenal.
Click to expand...

Good call apparently. Removed just one o-ring from the presentation side (lockbar o-ring still there) and cannot repeat the lock fail even when opening as softly as I can manage. Appears to lockup significantly deeper as well. Now......what to do about it. I do like the soft opening. Maybe that o-ring just got gummy? Hmmmm.....Also, fwiw...I purchased used off the exchange and this was NOT a problem initially. It has sat unloved for a few months once my Insingo showed up.
 
With both o-rings removed there is now a bit of lock-stick...like the ball is digging into the tang almost, particularly if opened harder.
 
The only way the o-rings can effect lockup is if they are too thick and prevent the thumbstuds from contacting the frame or only allow them to just "kiss" the frame. In this case, very early lockup, spongy lockup, or none at all would occur. This has been discussed many times over and Tim Reeve just addressed it again a few days ago on facebook. The o-rings, when the correct size is used, are simply for sound suppression and make no difference in lockup. The umnumzaan is designed without a physical stop-pin, such as is used in the Sebenza 21. On the Umnumzaan, the thumbstuds work as the stop pin. Therefore, the o-rings can even be completely removed, and it will make no difference in lockup percentage. All of this is based on the correct size of oring being used. O-rings can be made out of a variety of different materials and over time can become soft, brittle, hard, or do any number of weird things and the environment they are used in can change their consistency rapidly. For instance, some o-rings can't handle coming into contact with diesel. If they are exposed to it enough, they will become goo.
The easiest thing for Umnumzaan owners to do is order a couple sets of extra o-rings from CRK and they will be good to go for many years.
 
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