umnum test from poland

[Shing]

Guys, I am planning to order an Umnumzaan tomorrow, but now I am getting worried after reading this topic and watching the videos. Sigh.

It does make sense that the ceramic ball, once it digs a vertical groove in the tang, this groove could facilitate the closing of the knife with minimal force. It'll be like a roller ball rolling downwards in the groove. Anybody can comment on this? And boost up my confidence in this knife once again...

If you don't like it, you would have no problem selling it on for near the price you paid. It does seem odd in using what in effect is a ball race type arrangement to hold the blade open. I think a system to increase friction would be better such as putting serrations in the tang and interlocking serrations in the contact surface of the locking bar increasing the contact area of the mating surfaces and increasing the force needed to overcome the friction to close the lock compared to the ceramic ball arrangement.

 

[TLR]

whw-
If the umnum is the knife you've been wanting then get it. You've seen me interacting in this discussion. I am really interested in why that lock failed and in the umnum lock as a whole. I'm so interested mine just came in the mail about two hours ago. I got it off the exchange here and let me tell you my first impressions are that this is an amazing knife. I can only compare it to my small sebenza but let me tell you that this thing is a tank. Look I'm no lapdog for any maker. I have knives from a number of makers. I have spydercos, benchmades, microtechs and such and there are days and purposes that I will carry those other makers knives. There are crtain makers I put a high degree of trust in. If Sal from spyderco designs a knife I have no doubt that it will be a quality knife. If Chris Reeve designs a knife I have full confidence that it will be a well engineered, well thought out and quality cutting tool. That's not blind trust it comes from his track record and the knives of his that I own.

I say all of that to tell you to get it. One great thing about CRK knives is that they hold their value well. If you still have doubts then get a large sebenza. Worst case scenario is that later you can trade it out for an umnum when you see how he umnum fairs over time.

 

[Biginboca]

I think a system to increase friction would be better such as putting serrations in the tang and interlocking serrations in the contact surface of the locking bar increasing the contact area of the mating surfaces and increasing the force needed to overcome the friction to close the lock compared to the ceramic ball arrangement.

Shing,

Not trying to get base here, but comments like these and the look of the knife on your site make me believe that you have no idea what you are talking about.

How are 2 rough edges going to wear against each other in the long run as the knife is cycled over the years? They will wear in and then wear out, imo. Your comments and knives pictured seem to point to a lack of experience.

And coming to the factory forum of CRK to publicly reengineer and/or challenge your knives against the knives of the most reknowned, respected manufacturer in the world is just poor tastes. If you think you have great ideas quietly implementing them on your own forum or submitting them to Chris in private would be much more respectable, IMO.

Based on the behavior here I will not be considering one of your knives and I think I am not alone...

I hope everyone can learn from this thread.

 

[TLR]

Yeah I actually deleted the part of my thread giving my thoughts about shings idea right before I posted. At first serrations would be horribly hard to disengage but then they would wear quickly causing issues with tolerances. Ultimately I'd imagine you'd get some vertical bladeplay.

 

[bigmark408]

Guys, I am planning to order an Umnumzaan tomorrow, but now I am getting worried after reading this topic and watching the videos. Sigh.

It does make sense that the ceramic ball, once it digs a vertical groove in the tang, this groove could facilitate the closing of the knife with minimal force. It'll be like a roller ball rolling downwards in the groove. Anybody can comment on this? And boost up my confidence in this knife once again...

Actually you are incorrect....the ball enters the lock face on the blade from the side 90 degree from what you described.

Have no worries about the zaan...as has been said already, any knife can be made to fail.

Shings attempt at making Chris Reeve look like a novice is in bad taste.

Has anyone noticed that Chris Reeve has not dignified this thread with a response ?

His reputation and the proven longevity of his product do the talking.

Anybody that knows me, knows that i own and have owned several hundreds of all types of knives...CRK is not given my respect...they rightfully earned it.

 

[xzhang]

Shing, people are right, Strider's are not stronger than CRK's. Using more metal on the blade and making the handle bigger do not make the knife stronger. I have handled at least two dozens of strider folders, they can not beat CRK's in any way except the size.

 

[GigOne]

Guys, I am planning to order an Umnumzaan tomorrow, but now I am getting worried after reading this topic and watching the videos. Sigh.

It does make sense that the ceramic ball, once it digs a vertical groove in the tang, this groove could facilitate the closing of the knife with minimal force. It'll be like a roller ball rolling downwards in the groove. Anybody can comment on this? And boost up my confidence in this knife once again...

My EDC folder (RIL, liner lock, or frame lock) rotation consists of a custom and a Umnumzaan. In the past year and a half, I've been extremely pleased with everything about the Umnumzaan.

If you use the knife for its intended purpose, you'll have no worries. If you plan on using the knife to chop down trees, use it as a make shift foothold for mountain climbing, to disassemble concrete building, or perforate 55-gallon drums (or refrigerators), then don't make the leap, as there are tools available that are more capable in handling those tasks.

 

[Lycosa]

It would be nice if STR bopped in.

 

[Cotherion]

Been looking for an Umnum. But I think I prefer this issue addressed.

Because I'm worried. Even if I do not exert unreasonable loading which created the bb groove on tang, even in normal opening closing (I have a habit, I open and close my folders like clockwork. It's relaxing) cycles I would create the groove sooner or later.

Actually wouldn't it be better to increase contact area of lock to tang? I admit I'm unsure how to visualize the Umnum design but isn't the contact area one BB in the Umnum's case? Compared to Sebbie under same closing force wouldn't the Umnum's BB exert high pressure on BB tang and to the Titanium below it? Force/area = pressure thingy?r

Tq.

 

[Death's Head]

OK, first off, I'm impressed on how the Umnumzaan performed with these tests. I would be impressed with any folder to survive this amount of abuse. And clearly, that's what these tests are. I understand that the tester purposely came up with excessive testing with the intentions of observing the breaking point.
With that in mind, the test only proves how strong folders can be made. If one can make a conclusion from this SINGLE test, one can assume that the Umnumzaan is a sturdy folder, but the Sebenza is sturdier. I would say that both folders passed all the tests with flying colors.
But to conclude from a single test that all Sebenzas are better made than Umnumzaans is ludicrous. For one to make any sort of conclusion, one would have to make numerous tests in many more different environments.

 

[STR]

I'm not sure what I can add to this discussion but some things need to be mentioned in defense of the folder in question. I've watched all the videos and read what I could after using Google to translate.

First of all the knife took some pretty good testing in my opinion and seemed to do quite well. When the lock defeated it may well be that the lock lost spring tension and was no longer engaging the blade contact properly after having the memory reset to a different weaker spring tension. After all the tester apparently was hyper extending it on purpose from the looks of things. I suspect the lock was no longer moving in behind the blade as it did from the factory. Secondly, the lock may well have still had mud and/or water on the contact aiding the easy defeat by the time this happened. We don't know if it was dried first or not, but I suspect not. Thirdly, the shock of the impact to the spine can make the lock on an integral folder snap off the blade and this is particularly easy if the lock is not properly tensioned to get in behind the blade after being hyper extended. This lack of proper contact would also lead to some vertical movement and if I'm not mistaken that was going on later in the test.

In the hand is where this type of lock wins a lot of praise and with the fingers wrapped around the lock to secure it and even move it in further behind the blade even if the lock is not properly tensioned it is unlikely the lock would be unreliable at all. This is the benefit of the open frame lock vs a liner lock which as we know can fail this test also. These type things can take place one time where the lock fails miserably and pass it the next time you do the same thing making you wonder what happened differently the last time. Debris such as pocket lint, mud, sand, oil, water or other things can all play a roll in how the lock behaves. Personally after being soaked in the mud like it was and rolled around for a good bath repeatedly like that I would not be at all surprised to learn some greasy residue was left on the lock contact or blade or if the lube from the bushing or washers if there was any washed in to those areas. All these things contribute to lock behavior.

Lastly, never judge the entire line from one lock defeat. I've had Emerson knives fail on me miserably, Spyderco knives, BenchMades, Kershaws, Gerbers, Bucks, and many more but it does not mean all such knives of the same model are now crap just because your luck brought you the one lock of how ever many thousands were made that did defeat. Even if ten fail its still not adequate numbers to say the entire model is not to be trusted or that the company product line in general has to be used suspiciously from now on just because of this or any other video. Generally speaking its a good idea to be aware that any folder lock mechanism can defeat and use them all with caution and common sense. In the end the knife may have defeated a simple spine tap test but again, look at it from the stand point that the lock and the knife overall are still quite usable. The refurbish to bring it back up to snuff would most likely be all labor. This involving a good break down and cleaning of all parts, degreasing of the contact areas on both the blade and lock and probably springing the lock tension again to a new memory so it moves in to properly engage the blade, relube of the moving parts if needed and reassembly. My guess is the knife would be good as new again. But its just a guess.

STR

 

[Cotherion]

Lock springiness/stiffness is one thing, what about the gauging from the bb on the tang? Would it be ok to assume that will be negatively affecting the lock?

I'm hazarding a guess. Like certain framelocks which use the tip of the lockbar only to contact, wear occurs much faster due to the increase in pressure (same force but significantly reduced area of contact). For the Umnum the contact is only a bb (not sure gotta get clarification on this one)? Would it wear at the tang (like can be seen) till the bb create a channel thereby reducing effectiveness over time?

Tq.

 

[SteelSnob]

I agree with Biginboca. I thought Shing had some nerve to come talk down on or redesign Chris Reeve's work , especially when I saw Shing's work. Are you kidding me? Look at that folder on his site. That thing looks like it was made in some High School's Metal shop class.

 

[RICKSTER]

I agree with Biginboca. I thought Shing had some nerve to come talk down on or redesign Chris Reeve's work , especially when I saw Shing's work. Are you kidding me? Look at that folder on his site. That thing looks like it was made in some High School's Metal shop class.

The one I made in shop looked way better

Great post Steelsnob :thumbup::thumbup::thumbup::thumbup::thumbup:

 

[bigmark408]

Been looking for an Umnum. But I think I prefer this issue addressed.

Because I'm worried. Even if I do not exert unreasonable loading which created the bb groove on tang, even in normal opening closing (I have a habit, I open and close my folders like clockwork. It's relaxing) cycles I would create the groove sooner or later.

Actually wouldn't it be better to increase contact area of lock to tang? I admit I'm unsure how to visualize the Umnum design but isn't the contact area one BB in the Umnum's case? Compared to Sebbie under same closing force wouldn't the Umnum's BB exert high pressure on BB tang and to the Titanium below it? Force/area = pressure thingy?r

Tq.

Have no worries CRK folders have been used as worry beads for many years

 

[Cotherion]

I have no such worry with the Sebbie. I own quite a few titanium framelocks and the sebbie has good history (from many people's experience) so I'm still hopeful for a sebbie (searching for one in my $ range) for my open/close habit

However sad to say, though I was very interested in an Umnum, I cannot deny the issues or logic raised so far. Unless better explanation is given instead of "it's a CRK, it's gotta be good". Truthfully the CR name gives me peace of mind but it is not a 100% guarantee you see. Would be nice if Mr. CR himself participated in this thread.

 

[Biginboca]

However sad to say, though I was very interested in an Umnum, I cannot deny the issues or logic raised so far. Unless better explanation is given instead of "it's a CRK, it's gotta be good".

I have never read of an Umnum lock failing before. In fact, I don't think it's ever been reported on this forum until now and the knife it happened to has been shown in the pictures to have the lock previously overextended and also been severely used (maybe abused).

I have spine whacked 2 Umnumzaan's many times (hard) and had not a single failure. Of coure I do not purposely overextend my locks either. If you handle an Umnum you will see it takes great effort to move the lockbar that far and you would easily know you are damaging the knife when you are doing so.

If you pass by the Umnum due to this ridiculous thread you are doing yourself an injustice by missing out on what is the best made, highest technology, and most reliable in the long term folding knife ever made.

Why would Mr Reeve need to respond to this ridiculous thread? Wouldn't everyone's common sense give them the answers they need?

 

[Cotherion]

I know, I hope the overextension was the main cause but I hope if I can be confirmed/corrected, is the lockbar overextended after the failure/gauging or before? I'm not sure because I have really bad internet connection and can't check the polish site since I keep hanging/comatose (refering to internet connection).

But my question is what happens when the bb wears out a channel? What then? Not impossible or implausible since the contact area of bb to tang is small hence large friction/pressure.

However previously I liked the whole "Sebbie on Steriods" thing. That's why I was looking for one. I hope someone else (with money to experiment on) does another more acceptable experiment (with extreme data) since I'm interested in the limits of this folder.

I hope people understand, this design has not the years of history as with the Sebbie. Because of this I am unsure. Though I may not need super strength for my folders but I need to know it's limits and if it is weaker than the Sebbie then I'll get the Sebbie with my limited funds...

I live in a country where the price of a Sebbie/Umnum = cost of living for a month. Even so it ain't stopping me, I'm too fat anyways so prefer spending money on steel than on rice

 

[bearcut]

It is amazing that so many people can't understand the concept that gripping a framelock in the hand actually makes the lock interface more secure, ceramic ball or not.

Gee, maybe the rest of us ARE rocket scientists.

 

[whw]

I have been trying to visualise this issue since my last post. I don't have an Umnumzaan in my hand, yet. So my thoughts are based on assumptions only. But hear me out.

First, a question to all - If the detent ball (bb?) was removed, do you think the lockbar would still work? What do you think? Is the lockbar sufficiently close in proximity to the tang that the lock will still hold? This is an important question in my opinion because it gives insight into whether the locking mechanism solely depends on the detent ball, and/or whether the detent ball is there for other purposes as well eg. smoothness, minimise friction etc.

A post on page 1 of this topic by NYEFMAKER got me thinking. And it makes a lot of sense. Once again, I am only visualising this and sharing my thoughts.

An interesting test to say the least. My umnumzaan will close unless its fully locked open. When I open it " lightly", the poly "O" rings are not compressed. The lock engages only about 25-30% and the knife will close if folded closed like a slip joint pocket knife about 50% of the time. If I open it more forcefully and compress the "O" rings fully, it stays locked fully open and will not close. When locked fully, the lock engages 50-60%. This is about th only flaw I have found with the umnumzaan.

(Orientation - With the knife on its spine and the blade edge facing upwards to the sky, outside is on the left, and inside is on the right).

Now imagine this - the knife is opened, but not fully opened until the pins are really pressing firmly against the handle. The lockbar appears to be engaged ie. lockbar is overlapping a portion of the knife tang. HOWEVER, in reality the detent ball's contact point (and the contact point is only a dot on the surface of the ball) is actually on the outside edge of the tang. So when pressure is applied to the spine, the tang easily slips off the detent ball. And the remaining inside edge of the lockbar (ie. between the inside edge of the lockbar and the detent ball) is insufficient to hold/lock the blade so the tang slips off that as well and the knife closes ie. lock 'fails'. Perhaps this is what happened during the video test. The combination of the weakened lockbar (due to over extension) and dirt in the knife/pivot etc caused the blade to not fully lock ie the detent ball is precariously on the outside edge of the tang.

Is the slim inside edge of the lockbar (before contact with the detent ball) sufficient to lock the blade? Can some of the Umnumzaan holders test this out - Can you try to 'lock' the blade without the detent ball engaging (not sure whether the tension of the lockbar is too strong, but try to hold the lockbar out and put pressure by 'closing' the blade so that the blade sits on the slim inside edge of the lockbar). Then test whether the knife can close. If the knife can close, then it adds support to the above hypothesis on why the locked 'failed' (I'm secretly rooting that the inside edge of the lockbar is in fact sufficient to keep the knife locked.)

If the knife is fully opened and/or the detent ball in full engagement with the tang (ie. not on the edge of the tang but on its full surface), Nyefmaker's post above indicates that the lock is 100%. And most of the time, the tension of the lockbar is going to be sufficient to ensure that the lockbar is in full engagement. Not to mention the further safeguard when the knife is gripped, pressing the lockbar in even further.

But having to double check the knife to ensure that the detent ball is fully engaged (assuming that the 'flaw' in the locking mechanism is actually due to the detent ball not being fully engaged ie. the knife is not fully opened as discussed above), is going to make you second guess each time you use the knife, which is surely not good.

And on another note, since the detent ball is harder than the blade steel, it will wear/cut into the steel, as shown in the pictures, test by XZHANG, and feedback by others in this topic. So over time, as the knife experiences pressure on its spine during usage, the force on the blade making it close will cause the detent ball to bite into the tang, thus causing the 'groove/channel'. Over time, not sure how this affects the locking mechanism.

So back to the first question - will the lock still work without the detent ball? If yes, it's a relief because even if the tang is badly 'grooved', the lock should still hold because the lockbar face will eventually make contact with the tang and hold the blade in place. But if not, then once the knife is badly 'grooved' it's foreseeable that the blade can slip out and thus knife closing.

Anybody want to try removing the detent ball from their Umnumzaans to test out the lock without the detent ball!

I hope I explained the above clearly enough. Just some thoughts to share with the forumers here. Let me know your thoughts and feedback.