umnum test from poland

[Cotherion]

I thought that the carbide layer put on the lockbar face of some maker's knives is very very hard (i'm not sure if it's harder than the ceramic ball) but the fact that a ball is used on the umnumzaan should mean there's less wear than on the knives with carbides on the lockbar. does anyone know how these two materials compare in terms of hardness?

If a ball is used then because of the very small contact area then the resulting pressure is higher. Pressure=force/area.

Higher pressure can bring more wear. Like the harder you press on sandpaper makes it wear more. Guys please correct me if I'm wrong. Not much sleep last night.

 

[misterjuiceman]

If a ball is used then because of the very small contact area then the resulting pressure is higher. Pressure=force/area.

Higher pressure can bring more wear. Like the harder you press on sandpaper makes it wear more. Guys please correct me if I'm wrong. Not much sleep last night.

there's definitely more pressure if it's a proper sphere, but I figured the contact point is flattened out a bit. also, on my standard framelocks there isn't very much contact being made with the lockbar and tang. only part of the edge of the lockbar makes contact, and some are at 30-40% lockup.

 

[bigmark408]

Everyone is speaking of the Cerbec ceramic ball like it is what caused the lock up issue in the video and that is not the case...the ball did not fail !!

The wear on the lock face of the blade is normal....look at any frame lock that you own that has been used and you will see wear on the lock face from the titanium.

The lock failure in these vids is obviously due to the lock bar coming out of battery...i have adjusted many lock bars and can tell you for a fact ,the way he hyper extended the lock bar is going to cause it to not seat deep enough....the only way to make it correct again would be to disassemble the knife and bend the lock bar back.

I mentioned early in this thread that i noticed wear on the lock face of one of my zaans....that wear is over a year and several thousands of cycles....lock up is still solid with NO blade play in any direction.

Even if the ball were missing, the blade would not have closed like it did from a twig and finger spine whack.

This thread has become absolutely ridiculous (IMO).

Most here are trying so hard to find fault that they have lost there common sense.

For those of you haters, i suggest that you do not buy the zaan....it's your loss.

 

[bigmark408]

there's definitely more pressure if it's a proper sphere, but I figured the contact point is flattened out a bit. also, on my standard framelocks there isn't very much contact being made with the lockbar and tang. only part of the edge of the lockbar makes contact, and some are at 30-40% lockup.

Excellent point, not many can make the perfect lock up....if there were 100% contact between the 2 metals you would have a sticky lock....i have had customs that required a screwdriver to disengage the lock after a solid flick.

Most of the locks that work decent have a very small contact area.

IMO , Chris Reeve has done a masterful job with the frame lock design.

 

[xzhang]

I thought that the carbide layer put on the lockbar face of some maker's knives is very very hard (i'm not sure if it's harder than the ceramic ball) but the fact that a ball is used on the umnumzaan should mean there's less wear than on the knives with carbides on the lockbar. does anyone know how these two materials compare in terms of hardness?

It is NOT carbide layer. I don't know where did you get that information.
People do use TiCN or TiO2 as a coating, but no one use carbide on the lockbar.

 

[xzhang]

If a ball is used then because of the very small contact area then the resulting pressure is higher. Pressure=force/area.

Higher pressure can bring more wear. Like the harder you press on sandpaper makes it wear more. Guys please correct me if I'm wrong. Not much sleep last night.

good point! :thumbup:

the other key factor to the wear is the surface roughness. I believe the umnum's have less wear than other knives under normal use because a umnum has a ceramic ball that provides a much smoother surface than titanium or steel. However, when the force applied is increasing, the wear becomes more force/pressure-dependent.

In that case, umnum's can wear much faster than other knives because of the huge pressure created on the interface.

 

[ben191]

"I believe the umnum's have less wear than other knives"..."umnum's can wear much faster than other knives"

???

btw. i love my umnum and id go as far as to say its my favorite knife ever.
i got a pretty anodized blue one a week ago. think im going to have to grab a tanto version when one pops up, simply beautiful.
Still do love the simplicity of my sebenza, but as they say, variety is the spice of life.

 

[misterjuiceman]

It is NOT carbide layer. I don't know where did you get that information.
People do use TiCN or TiO2 as a coating, but no one use carbide on the lockbar.

actually, Rick Hinderer and Tom Mayo have both said they use a carbidizer on the lockbar face. :thumbup:

edit: this isn't the first time someone has flat out said i'm wrong about the carbidizer. i don't understand why using a carbidizer is so unbelievable.

 

[xzhang]

"I believe the umnum's have less wear than other knives"..."umnum's can wear much faster than other knives"

???

I assume you dont understand what I said in my last reply.
the speed of wear is a function of several factors, such as surface toughness, force, sliding speed, etc.
when the force is small, the surface toughness plays a large role in the wearing system. that is why I believe umnum's have less wear under normal use because they use the ceramic ball.
when the force is large, the wear becomes more force-dependent. And I believe umnum's wear much faster than other knives because of the very small contact surface that leds to the huge pressure.

 

[Cotherion]

Everyone is speaking of the Cerbec ceramic ball like it is what caused the lock up issue in the video and that is not the case...the ball did not fail !!

The wear on the lock face of the blade is normal....look at any frame lock that you own that has been used and you will see wear on the lock face from the titanium.

The lock failure in these vids is obviously due to the lock bar coming out of battery...i have adjusted many lock bars and can tell you for a fact ,the way he hyper extended the lock bar is going to cause it to not seat deep enough....the only way to make it correct again would be to disassemble the knife and bend the lock bar back.

I mentioned early in this thread that i noticed wear on the lock face of one of my zaans....that wear is over a year and several thousands of cycles....lock up is still solid with NO blade play in any direction.

Even if the ball were missing, the blade would not have closed like it did from a twig and finger spine whack.

This thread has become absolutely ridiculous (IMO).

Most here are trying so hard to find fault that they have lost there common sense.

For those of you haters, i suggest that you do not buy the zaan....it's your loss.

I remember long time ago I hyper extended a Kershaw Shallot and it failed on me (but luckily small injury) while I was cutting some boxes. Hyper extension really does throw the basic/normal assumptions outta whack so if there is a pic in the polish site which shows it being hyper extended then it throws the whole test into question. Basically for a fairer test he/she/tester shouldn't have done that. Possibly some stuff (mud/grit/stuff) got caught and combined with weak lockbar stiffness the lockbar rested before the bb went into place = twig or finger induced failure.....

However to be fair I thnk the emphasis was not the bb failure (bb was apparently 1. indestructible and 2. pretty solidly put in place, ain't coming out) but the effect of the bb on tang, the groove effect. Which at this point I'm not confirmed it is a good thing cause...

there's definitely more pressure if it's a proper sphere, but I figured the contact point is flattened out a bit. also, on my standard framelocks there isn't very much contact being made with the lockbar and tang. only part of the edge of the lockbar makes contact, and some are at 30-40% lockup.

... makes pretty good sense and wear will increase contact area between bb and tang. Which in first place is better than titanium and tang (cases where titanium only contacting by a tip) which titanium (being softer than bb or blade material) wears out mucho faster than the bb. BB being so hard it results in tang being the one worn instead of the bb.

Conclusion:
1) In cases where the tester hyper extends the lockbar then the lockbar is severely affected. I know, I hyper extended my Kershaw Shallot (I was young/stupid) cause it seems the lockbar was in very deep (Shallot owners speak up ) but it was normal. My hyper extension to reduce the travel resulted in something like a slip joint. Tester compares to Sebbie which in normal circumstances is fair but he/she did not previously hyper extend the Sebbie. I know cause he/she had no reason to since Sebbie had no bb for him/her to investigate.

2) BB wearing a groove in the tang is (for now in my assumption) neither a good or bad thing. Though increase wear can create a channel but the increased contact area is also a result. My titanium framelocks have a long life with the soft (softer than bb) titanium so I can expect longer life with Umnum. And instead of carbidizing (spelling?) the lockface, CR incorporates a bb which is smoother and more consistent in contact point/area so to ensure consistency. The gauging (in polish test) does not mean anything since I remember seeing a ti framelock failure (in extreme tests) where the framelock contact area to tang was sheared off in extreme loads/impacts. I prefer a bb induced channel compared ot shearing of lockbar face.

Final Conclusion: I am unsure

Just kidding, these tests are not enough unless hyper extension issue is tackled.
Secondly channel by bb wear need to confirm the long term effect (which in theory is not too bad) by Zaan owners in BF (periodically in the future, sorta like a real life experiment) and perhaps by another, more controlled, test (if want to induce failure or whack onto fridge ).

Sorry for long wind. Words in mind is hard to bring into screen...

 

[misterjuiceman]

I think if the ceramic ball wearing into the tang were an issue, then Chris Reeve would have carbidized the tang of the blade (I believe this can be done). from what I've heard, it's not a very complicated process; it's similar to using an etcher, and the device is only around $180.

 

[bearcut]

actually, Rick Hinderer and Tom Mayo have both said they use a carbidizer on the lockbar face. :thumbup:

edit: this isn't the first time someone has flat out said i'm wrong about the carbidizer. i don't understand why using a carbidizer is so unbelievable.

You are correct.

I just bought a Hinderer and the lock face releases perfectly, straight out of the box. Mayos never stick either. I don't know why every knife maker doesn't do this. It's a no-brainer.

 

[misterjuiceman]

You are correct.

I just bought a Hinderer and the lock face releases perfectly, straight out of the box. Mayos never stick either. I don't know why every knife maker doesn't do this. It's a no-brainer.

does anyone know what CRK does for the Sebenza? Kevin Wilkins says that heat treating the lockbar face won't increase the hardness, so if the Sebenzas tend not to stick, then it's probably not that.

 

[Haze]

From what I have heard, read and seen the Sebenza lock bar is case hardned and also has the oxide layer left on it from the heat treat process at the contact area.

If you look at your Seb. you can clearly see the dark patch that goes from the lock face over the detent side of the lock bar.

 

[knifelife]

Not really up on all the techy stuff,but 2 things I'd like to add.
(1)I liked the Seb because it was a simple,locking bar,blade,handle=good stuff,by adding balls and pivots that need a special tool the Umnum has become a non starter for me.
(2)Shing makes some great knives,never own a locker of his,but his slippy's and fixed are excellent,as is his service and comm's.
Just my 2 penny worth.

 

[bearcut]

If you knew the advantages of using two thumstuds instead of the single bar for a blade stop you might change your mind.

Question: What do Strider, Hinderer and CRKs Umnumzaan all have in common, and why do they all feature this design?

Answer: Chris saw the light.

 

[misterjuiceman]

If you knew the advantages of using two thumstuds instead of the single bar for a blade stop you might change your mind.

Question: What do Strider, Hinderer and CRKs Umnumzaan all have in common, and why do they all feature this design?

Answer: Chris saw the light.

what exactly are the advantages? i can only think of potential disadvantages, as in designs like strider's (not hinderer's or CRK's), only one of the thumbstuds makes contact, so it seems like that could bend the thumbstud.

 

[on_the_edge]

Cotherion,
A scientifically proven cause of lock failure on that Umnumzaan may never be a reality, and in all likelihood, it won't. Even knowing without a doubt what the cause of the lock failure was, you may then question whether there are other things that would cause a lock failure, and you may question if you yourself would ever do something to cause a lock failure. Those are all valid concerns at this point, and they are all unknowns. There is a known here though, a guarantee that "should" put your mind at rest:

Get one. Try it out. Play with it. Use it in whatever way you ordinarily use a knife. Maybe try to push its limits a little. See if it instills confidence in you. See if you grow to like or love it. Here's the guarantee part--if you don't want, need, like, or love it, if you have not damaged it, you can sell it for most of your initial outlay. It happens every day on the X and you can do that too if that is your wish. You may be out $40, but you most certainly won't be out $400. Is $40 too high a price for admission, where you can satisfy yourself and make up your own mind?

 

[ben191]

This is just my own opinion. A knife speaks to our very instinctual desire for a tool which provides protection and preparedness. It also speaks to our most refined sense of aesthetics with its simple curves and lines. The technological potential in a folding knife is huge too. Most of us are fascinated by how something can remain elegant and simple, while having a huge amount of technology in it.

Anyways, i feel that these knives have really come so close to a level of perfection rarely seen in this world, and since i think they are paving the way, i can definitely understand why people got heated to learn that they arent perfect. But its good that people demand perfection as these consumers will push for and fund new designs.

Obviously anyone in the know, knows that the Umnumzaan will stand up to most anything that people would throw at a folding knife. I really like mine and carry it everyday. Not saying i could do any better myself, but i can also see why people feel they should be able to have something that can stand up to way way more than they can throw at a knife, given the creativity of people like Chris Reeves and the incredible properties of the materials he uses. Id also like to see a proper test of the Umnum since i dont want to push mine to that point...

 

[whw]

I've just ordered mine today. Can't wait to get it!