Umnumzaan Prototypes

G

GoodGuy

Joined
Feb 28, 2005
Messages
391
I know that the Umnumzaan prototypes I see for sales show 1 / 20 on their handles (and boxes, I think). Were there only 20 prototypes all together, or were only 20 released for sale by CRK?
 
TNK and other knife dealers had Umnumzaan's for sale. I dunno how many proto's were made.
 
I know there were 20 prototypes released for sale, hence the mark 1/20. Just guessing, but I would imagine several prototypes were produced for initial design, fitting, and mock-up purposes.
 
GigOne said:
I know there were 20 prototypes released for sale, hence the mark 1/20. Just guessing, but I would imagine several prototypes were produced for initial design, fitting, and mock-up purposes.
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That makes sense to me, and I'm guessing that's the case. The 1/20 marked knives are likely "perfections" of the model (probably after a lot of prototypes) released to collectors.
 
GoodGuy said:
That makes sense to me, and I'm guessing that's the case. The 1/20 marked knives are likely "perfections" of the model (probably after a lot of prototypes) released to collectors.
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I was able to play with a prototype at Blade Show. WOW. . . . .what a knife !

Received my non-prototype today and my feelings haven't changed ! Love my Sebbies, but WOW. . . . .what a knife ! :D
 
Yes, 20 were specifically made to be sold at the Blade show and all 20 are marked "1/20". I agree, I'm sure there are some internal prototypes but I doubt those will ever find their way out of CRK's building.

-Troy
 
As with all product developments, there were several "proof of concept" experiments to test different aspects of the Umnumzaan, test-driving ergonomics, mechanical fit, pivot operation and robustness, style/appearance, and more. Many of these experiments did not even resemble the final product, except perhaps in the aspects in which they were meant to test. Many of these experimental pieces would not be tools you'd actually want to carry. The first 20 protos are the first Umnumzaans that are beyond proof of concept, and are true prototypes of what is being shipped today.

I don't think I can rattle off all of the differences between the protos and the production models, but here are a few:
In the protos, the thumbstud rests on the lockbar in the closed position. A ball mounted in the handle supports the otherwise cantilevered lockbar to support this bladestop method. (Yes, this is hard to imagine if you don't have a proto right in front of you. Troy, I think I may have pointed this out to you and/or your dad at Blade. Your bottom view image of your proto Umnumzaan lockbar shows the support ball). In the production model, the blade is supported by the non-lockbar handle slab, and the ball that I described earlier has been removed.

In the production pieces, the cross-hatch pattern has been removed from the lockbar to be less abrasive on the fabric to which the knife is clipped.

The lockbar spring constant has been decreased in the production model.

There are several slight changes here and there in both the production blade and handle for improved ergonomics and aesthetics.
​
I’m sure, just as in the case of the Sebenza, that there will be many more refinements in the Umnumzaan throughout the life of the product. Chris is one for continuous improvement in design, materials, and process.

Fooj
 
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Fooj, what do you mean by "the lockbar spring constant has been decreased in the production model"?:)
 
cutter17 said:
Fooj, what do you mean by "the lockbar spring constant has been decreased in the production model"?:)
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Sorry -- I tend to talk in the academic terms that get relentlessly hammered into the heads of young impressionable engineering students :o. . . In a spring system, F = kx, where F = the force applied to the spring (in this case, the lock bar), x = the distance that the spring moves, and k = the spring constant, which can be thought of as the stiffness of the spring. In short, Chris thought the lockbar didn't need to be quite that hard to disengage, and adjusted it accordingly in the production model.
 
Thanks Fooj! It was very interesting to read. It is kind of strange. I want my proto to be as good as possible, but at the same time I want it to be different from the production model. What you told about the lockbar spring has been decreased is it related to how far the lockbar moves? On my proto travels the lockbar at least 90 percent. Is it the thing with all protos?
 
swe said:
Thanks Fooj! It was very interesting to read. It is kind of strange. I want my proto to be as good as possible, but at the same time I want it to be different from the production model. What you told about the lockbar spring has been decreased is it related to how far the lockbar moves? On my proto travels the lockbar at least 90 percent. Is it the thing with all protos?
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swe,

The spring constant is not related to how far the lock bar engages, only the force it takes to disengage the lock. On my proto, the lock bar travels ~ 90% as well. I recall all of them to be like that that I saw. I don't know what the production spec is . . . now you've got me curious.

Fooj
 
Fooj said:
swe,

The spring constant is not related to how far the lock bar engages, only the force it takes to disengage the lock. On my proto, the lock bar travels ~ 90% as well. I recall all of them to be like that that I saw. I don't know what the production spec is . . . now you've got me curious.

Fooj
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Thanks again for your answers! One more question: The ceramic ball on my proto, the one on the lock bar also serves as lock bar stop. It makes it impossible to open the lock to much and destroy it. Doesn´t the production knives have this feature?
 
Fooj said:
swe,

The spring constant is not related to how far the lock bar engages, only the force it takes to disengage the lock. On my proto, the lock bar travels ~ 90% as well. I recall all of them to be like that that I saw. I don't know what the production spec is . . . now you've got me curious.

Fooj
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Thanks for the clarification Fooj. On my production Umnum., the lockbar travels about 50 to 60 percent.
 
Good information. I appreciate all the posts. I went ahead and purchased one last week. It was pricey ($1,400), but it's a pretty neat folder.
 
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