Umnmzaam insights, please?

R

Rminio

Joined
Oct 2, 2010
Messages
44
Gentlemen,
is there a link to better understand how the Umnumzaam works? Details on the ceramic ball system, why the framelock cut is inside the grip and not outside, the washers and the pivot, why the harpoon swedge on the blade...there's something on CRK website but it just made me hungry to know (and see, without disassembling my new knife) more.

Thanks
 
Ceramic ball system uses a single ceramic ball (except on the prototype, that has two) on the lockbar face, so that it acts as a detent, and seemingly seamlessly it locks into the tang of the blade via an almost rolling motion (the ceramic ball is firmly in place, but the movement of the lockbar will kind of make it roll into position).

the washers are perforated to allow for lube to get stuck in the holes so that you don't have to take it apart as much. harpoon swedge is for doing things you wouldn't want to screw up your blade doing, like trying to start a fire.

as for the framelock cut out, that's just how CRK does it. there doesn't seem to be a discernible difference either way, I've got Mayo customs that have it both ways, and they seem to be more or less the same in terms of lockbar performance. I've heard tests have been done, and one is no less secure than the other, despite what the boys at Strider say. What I think is even more important than the side of which the lockbar cutout is on, is the thickness of the remaining titanium in the cut-area, and the style of the cut. CRK cuts theirs so that it takes a little bit more force to move the bar, but it'll lock up securely, and you won't need a Hinderer lockbar stabilizer unless you're a gorilla.
 
One quick thing that I think is very interesting.

Do not underestimate the strength of the ceramic ball for lockup. I have been discussing heat treating the framelock face of folders with a well known maker. Heat treating a lock face as with the Sebenza can create a layer after layer of strength. If done properly it can be equal to the strength of ceramic and can even withstand sand- beadblasting. I was one skeptic of the ceramic ball lockup, I thought why put something like that in when you can heat treat Ti. But since have changed my mind.
 
I love the ceramic ball lock. Nothing beats my Umnumzaan for smoothness opening or closing.
 
Rminio said:
Gentlemen,
is there a link to better understand how the Umnumzaam works? Details on the ceramic ball system, why the framelock cut is inside the grip and not outside, the washers and the pivot, why the harpoon swedge on the blade...there's something on CRK website but it just made me hungry to know (and see, without disassembling my new knife) more.

Thanks
Click to expand...

Skipping the details, I would add general ergos to your list. I had an Umnu that I sold because it just didn't work for me. I had the same thing happen with a (superb!) AG Russell Acies. Both are exceptional knives, but neither worked for me...so the technical details didn't matter, in the end. Too bad, in both cases, but there are a lot of other great knives to choose and use.
 
My very few criticisms of the Umnumzaan have to do purely with the ergonomics. I don't like how the clip is even with the lock bar of the knife, the way the Sebenza's clip is further towards the middle is more comfortable in the hand; the Umnumzaan clip makes hotspots on my pinky and ring finger where I grip it in my hand. The cut out of the titanium near the blade tang has a corner that is a little sharp--I wish that they had rounded the corner off more.

Otherwise the knife is just incredible. Very solid in the hand - mine has no bladeplay - it feels entirely different from the Sebenza due to being slightly thicker overall. Though ergonomics take a hit for me, I don't think that it is going to slip from my grip in anyway.

The ceramic ball is ingenious, and the bladeshape is well thought out. The swedge is for scraping or striking firesteels, the straight portion is for the index finger, and the curved portion is for the the thumb.
 
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