Umnumzaan Lock-Squeeze question

peppercorn

peppercorn

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I recently acquired an Umnumzaan from a friend here on the forum and just tonight set to bushcrafting with it. It performed flawlessly and I could not be happier with this great knife.
However, I noticed that after about an hour of camp prep and making fuzz sticks the lock bar/ ceramic ball was all the way against the opposite handle. The work I had been doing with the knife required a tight grip to be sure but nothing unusual for typical fire building.

Is this normal or is it too much travel? When I just open the knife it locks in the 80% ish zone as determined by where the ball rests. But, when you really grip the knife, as in real usage, it slides all the way to the opposite handle.

Thanks for any and all input.
 
Mine, brand new, did the same thing. If you notice, the ceramic ball is positioned on the corner of the frame lock bar. That way, it is in contact with the side and rear of the blade. So if it travels all the way to the other side, that ceramic ball is always in contact. Clear as mud?
 
BOBO said:
Mine, brand new, did the same thing. If you notice, the ceramic ball is positioned on the corner of the frame lock bar. That way, it is in contact with the side and rear of the blade. So if it travels all the way to the other side, that ceramic ball is always in contact. Clear as mud?
Click to expand...

.

Yes, clear as mud...Lol.

Actually it does make sense and as I looked at it in natural light, better light, this morning I could see that, even against the opposite handle, the ball is still in a good position relative to the back of the blade.


Thanks BOBO!
 
but anyhow, if the lock travels over to the other side, something has given way to something else...
I'm not sure how to interpret this, but locked should be locked. Not 80% some of the time and 100% some of the time.
what has been displaced?
 
It's like this. If I just open it to say just look at it, the lock bar rests in the 80% ish range. I can cut something that doesn't take much force to cut, and therefore a relaxed grip, like a piece of paper and it stays in the same range. But when I have to really grip hard the lock bar slides that extra distance. So, I am not sure if anything is giving or if it is just a matter of some pressure applied pushing the bar to its ultimate stop point by taking up some slack along the way?
 
From my previous thoughts on the Umnumzaan's overall design, I think this is normal / as designed. The lockup is (in my mind) adjustable in a certain sense. Simply opening the knife or giving it a light flick doesn't necessarily move the lockbar to the deepest possible lockup. Either way it's "locked" in a sense that it won't become unlocked – and thus unsafe –*but it can gain a "tighter" lockup. Similar to ratcheting down a strap.

Also as noted the way the face of the lockbar is constructed it appears further over then it really is.
 
I have had my zaan since last fall and have used it quite heavily as I have stated and shown in many posts. My normal lockup is in the 50% range. When I use it heavily with a very firm and tight grip, I have seen my lockup go to the 80% range or so. This is normal as my sebenzas have done nearly the same thing when using a firm/tight grip. This is pretty normal for a framelock. No worries, use it and enjoy it. If you ever have any issues with it, knowing that CRK will make it right is the reason I only buy knives from them now a days !!! Enjoy !
 
I called CRK today to check on the status of a knife they are servicing for me so, while I was at it, I asked about the lock up on the Zaan.
I was told that what I am experiencing is completely normal and that there can be enough movement when gripped tight that the ball can hit the opposite scale and that it should not represent a problem now or in the future. I was also told that if I had the slightest concern about it that I could send the knife in at any time for evaluation.
 
Recieved a left handed Umnumzaan this morning (dated June 8th 2010 so basically new from factory) and the lockup is around 80%-85% but when gripped tightly as described in this thread, the ceramic ball touches the other end. This is normal right? I'm guessing it is as it would've left the factory like this. :confused: Lockup is still solid and perfect though.
 
greendestiny said:
Recieved a left handed Umnumzaan this morning (dated June 8th 2010 so basically new from factory) and the lockup is around 80%-85% but when gripped tightly as described in this thread, the ceramic ball touches the other end. This is normal right? I'm guessing it is as it would've left the factory like this. :confused: Lockup is still solid and perfect though.
Click to expand...

The way I see it, as long as the blade opens and 'locks' open, there's no problem. The further over the lockbar is, the more secure the lockup.
 
On the umnumzaan, you have the o-rings around the studs, its plausible that under heavy use, they compress and your blade travels up a little more, increasing lockup. The tighter you squeeze the knife, the lockbar wants to slide on the angle on the tang, which could compress the o-rings.
 
The O-rings make no difference to the lock up. They are just there to act as a dampner to reduce noise and the like.

The O-rings on my Umnumzaan became loose a while back so I just took them off and haven't bothered to put new ones on yet. That did nothing to the lock up at all.
 
safetyman said:
The way I see it, as long as the blade opens and 'locks' open, there's no problem. The further over the lockbar is, the more secure the lockup.
Click to expand...

Thanks guys but what about the ceramic ball touching the other end? There's no problem there too?
 
Pepper

I only have CRK Sebenzas. My main user, a largr micarta 21 locks normal at about 75%. Very tight and secure. For normal use including carving, food prep, and utility work the lock stays put. The hardest task I put it through was when I was with a couple buddies wheeling in the woods. We were riding down a river and we came to a rocky waterfall. We wanted to attempt to ride down it but could not tell how deep the water was below. I found a nearby vine and all I had was my sebenze. I started to cut the 2 inch thick vine with it. First end I muscled the sharp blade right through. The second end was a little harder. I was basically putting all of my 225 lbs down on the blade plus all my strength all while pivoting the knife side to side to force it through. Chopping was not an option.

Anyhow when I was done the lock was at 100 %. I closed and opened and right back to 75 %. It is still kicking and no damage I can see. I remember CRK stating the locks are springs and common sense would lead you to this result if you look at it this way.

I was glad mine locked to 100 %. It was TIGHT with no chance of moving open on me.

Later,

Kevin
 
Btw, we used the 8 foot section of vine to see how deep the turbulent water was. When it disappeared straight to the bottom we decided to make a detour :)
 
this is a great thread btw! i have been wondering the same exact thing about my Umnum.

Josh K said:
From my previous thoughtsEither way it's "locked" in a sense that it won't become unlocked – and thus unsafe –*but it can gain a "tighter" lockup.
Click to expand...

this line pretty much explains why my concern for this issue has been minor. Although this deep lock up has concerned me, i've never once felt in danger of this knife folding up on me. However, if the lock bar starts slammin the other slab i'm sending it in to CRK.
 
IMG_0053.JPG


Check out this picture from one of the prototype Umnumzaans. (Credit where credit is due.)

Seems like the prototype had something that would prevent this. Not that I think it's an issue, and probably removed to keep it simple. It doesn't look like an easy thing to do place a ball behind the lockbar.

Any ideas?
 
^^ I don't see how the extra ceramic ball on the protos would prevent the lockbar from traveling over to 100% lockup...:confused:.
 
safetyman said:
^^ I don't see how the extra ceramic ball on the protos would prevent the lockbar from traveling over to 100% lockup...:confused:.
Click to expand...

Oh. :foot: I missed the title.

Someone (in another thread) has commented about vertical lock bar play (being able to push the lockbar closer to the handle) and it seems this ceramic ball would prevent that.
 
Josh K said:
Oh. :foot: I missed the title.

Someone (in another thread) has commented about vertical lock bar play (being able to push the lockbar closer to the handle) and it seems this ceramic ball would prevent that.
Click to expand...

Yep, if that was the problem then the extra ball would definitely fix that :). It would be a cool if the productions had those too..
 
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