Bring On The Umnumzaan Trio

[rororo64]

Yea I heard from another member that he got a s35vn startac umnumzaan yesterday

 

[PAZach]

Yea I heard from another member that he got a s35vn startac umnumzaan yesterday

Nice collection. I'm in the market for an Umnumzaan. Does anyone know if they are making it with an S35vn blade?

 

[marthinus]

Great trio!

 

[Medic1210]

Attn: rororo64,

Called WC the other day and inquired if they had plans to switch the Startac steel over to S35VN and they said they would keep it S30V- with no plans on change over, anytime soon.

Considering Wilson isn't actually making the Startacs, I can't imagine they have any say in what blade steel is used. It will come with whatever blade steel CRK starts making them in. Whoever told you that very likely just fed you a line of bull.

To the OP... in the lockup photo, I couldn't help but notice the middle one is closing in on the 90% or more lockup. Does this concern you any? Also, since the studs have the polymer o-rings that bump against the handle as a blade stop, does the lockup change depending on how hard you flick open the knife? Does it lock up further if you open it hard due to compression of the o-rings?

 

[DallasSTB]

Considering Wilson isn't actually making the Startacs, I can't imagine they have any say in what blade steel is used. It will come with whatever blade steel CRK starts making them in. Whoever told you that very likely just fed you a line of bull.

To the OP... in the lockup photo, I couldn't help but notice the middle one is closing in on the 90% or more lockup. Does this concern you any? Also, since the studs have the polymer o-rings that bump against the handle as a blade stop, does the lockup change depending on how hard you flick open the knife? Does it lock up further if you open it hard due to compression of the o-rings?

I imagine that when CRK changes all of the Umnumzaan blades over to S35VN after the current stock is used up, any new orders from Wilson with fall in line.

To Medic - the lockup on the 'Zaan is different from a Sebenza. The contact point is the ceramic ball at the end of the lock tab. Because the ball is inset into the titanium a bit, the lock tab appears to have greater travel than the lock tab on the Seb. I've been told that even though it "appears" to have further travel, the actual contact point for the tip of the ball against the blade tang is still set at 50-75%.

 

[nyefmaker]

I imagine that when CRK changes all of the Umnumzaan blades over to S35VN after the current stock is used up, any new orders from Wilson with fall in line.

To Medic - the lockup on the 'Zaan is different from a Sebenza. The contact point is the ceramic ball at the end of the lock tab. Because the ball is inset into the titanium a bit, the lock tab appears to have greater travel than the lock tab on the Seb. I've been told that even though it "appears" to have further travel, the actual contact point for the tip of the ball against the blade tang is still set at 50-75%.

When I initially bought my first umnumzaan it had a 50% lock-up...... For sebenzas, I always look for a 50% lockup or there abouts and usually pass on ones showing the 80-90+% range. I just feel the 50% gives lots of room to wear over many years of use before any lock-up treatment by crk is needed. Whether this is a valid observation, I am not sure, just what I perceive and prefer. CRK specifications for sebenza lock-up is 50-75%..............Back to the umnumzaan, my fist one was in the 50% range and I passed on many used ones as I saw them in the 75% range. Every once in awhile, being at 50% and when sometimes dirty, my umnumzaan would close. I never got hurt which is good. Upon contacting CRK and talking with Chris personally about it, he informed me that the lock-up for the zaan is spec at 75% because the ceramic ball is bigger, the lock-up point is different. At 75%, the zaan is right at home and is at full lock-up. I sent my zaan to Chris and he adjusted it to where it should be ( 75% ) lock-up. Now its basically a fixed blade when opened and never had an issue of any kind, even when dirty and linty. My initials thoughts on the zaan lock-up were wrong and in past threads I stated as such. Oh how many zaan's I passed up thinking the 75% was too much. So I am just clarifying that when seeing an umnumzaan in the 50% range, it is out of spec. It does not follow sebenza specs ( 50-75% ). It starts at aprox. 75%. If you look down into the zaan, you will see that it will never go over to 100% lockup because of the larger detent ball. So I would estimate umnumzaan lockup to fall between 75% to say 90%.

 

[Medic1210]

Can someone post a closeup photo of the ceramic ball that makes contact with the tang? I'm just having trouble picturing how this works, or why it was done over solid lockbar to tang contact like on the Sebenza. Does anybody have or can take anybody take a photo of the lockbar scale removed so I can see the ball that is in the end? Hearing of the knife closing is making me rethink my desire to have one of these knives.

 

[xtal]

Can someone post a closeup photo of the ceramic ball that makes contact with the tang? I'm just having trouble picturing how this works, or why it was done over solid lockbar to tang contact like on the Sebenza. Does anybody have or can take anybody take a photo of the lockbar scale removed so I can see the ball that is in the end? Hearing of the knife closing is making me rethink my desire to have one of these knives.

Check out the Umnumzaan takedown videos on Youtube. Many of them show a closeup of the ceramic ball.

 

[Medic1210]

Ok, so I found some images of the detent/lock ball. I can only imagine that Chris was just trying to be unique with this design. Looks to be a form over function thing to me, because you can't argue that the lockbar of the Sebenza just flat out works... Like a vault. I've never heard of a Sebenza closing on someone, and if it has, I'm betting the lockbar tension has been pulled out of spec to make the knife easier to open and close. I do remember seeing a video of an Umnum being used hard, and the guy was able to tap the spine with his finger and get the lock to fail. I do seem to remember reading a followup from CRK that the knife was returned and found to have a lot of pocket lint clogging up something in the lock, preventing it from making full lockup. Not sure, but considering these things are carried in a pocket, pocket lint is to be expected, and should never cause lock failure. Anyway, I guess my concern with the design is, you go from having a large contact area on the blade tang to now a very small contact area. Why intentionally decrease the lock surface area that contacts the blade?? I also know that the ceramic ball on my Sebenzas polishes the area where it contacts the blade during opening. I can only imagine that the same thing is happening to the tang on the Umnum. Maybe I'm overthinking this, but to me, it seems that after the blade is polished enough, it could allow the lock to slip and fail under pressure. Again, this may not be an issue at all, but it's hard to argue that the Umnum does have a history of lock failure on more than one knife (the OP of this thread, and at least one other from those videos). Are there more? I guess I just trust the lockup on a Sebenza more than I trust the lockup on the Umnum, which sucks, because I really like the design, and wanted to purchase one.

 

[Medic1210]

Looking at the lockup on the middle knife above again, it actually looks like the detent/lock ball is touching the opposite handle. Am I seeing that right? If it's not touching, it has to be very close. That's normal?

 

[ssblood]

Medic, mine has approx 3/32" space between the locker and the other slab when opened. It locks up at around 75%. IMO it would take an amazing amount of force to overcome this. I don't see how anything short of wedging something between the lock bar and other slab could cause the lock to fail on mine. I've been disappointed many times on 100-200 dollar knives. Had an SMF I wouldn't have taken over a para2. I spent a weeks pay on this knife and honestly feel I got my moneys worth and then some.

 

[nyefmaker]

Ok, so I found some images of the detent/lock ball. I can only imagine that Chris was just trying to be unique with this design. Looks to be a form over function thing to me, because you can't argue that the lockbar of the Sebenza just flat out works... Like a vault. I've never heard of a Sebenza closing on someone, and if it has, I'm betting the lockbar tension has been pulled out of spec to make the knife easier to open and close. I do remember seeing a video of an Umnum being used hard, and the guy was able to tap the spine with his finger and get the lock to fail. I do seem to remember reading a followup from CRK that the knife was returned and found to have a lot of pocket lint clogging up something in the lock, preventing it from making full lockup. Not sure, but considering these things are carried in a pocket, pocket lint is to be expected, and should never cause lock failure. Anyway, I guess my concern with the design is, you go from having a large contact area on the blade tang to now a very small contact area. Why intentionally decrease the lock surface area that contacts the blade?? I also know that the ceramic ball on my Sebenzas polishes the area where it contacts the blade during opening. I can only imagine that the same thing is happening to the tang on the Umnum. Maybe I'm overthinking this, but to me, it seems that after the blade is polished enough, it could allow the lock to slip and fail under pressure. Again, this may not be an issue at all, but it's hard to argue that the Umnum does have a history of lock failure on more than one knife (the OP of this thread, and at least one other from those videos). Are there more? I guess I just trust the lockup on a Sebenza more than I trust the lockup on the Umnum, which sucks, because I really like the design, and wanted to purchase one.

You can see the lock-up on my umnumzaans are all pretty much the same. The lock-up spec on the zaan is 75%+. Much unlike the sebenza which is prime at 50%. At 75%+, the ceramic ball in centered in the rear blade tang for a solid lock-up. My first umnumzaan was out of spec at the 50% range and that was the only reason for closure as the lock was not engaged flush to the spec. point. This was remidied by CRK and I have had no issues with it since. I was wrong in thinking the umnumzaans lock-up% was the same as the sebenza. When discussing this with Mr. Reeve, he explained the lock-up to me fully. I admitted I was wrong in my thought process then and admit it now for those that may question the umnumzaan. I stand behind the umnumzaan in form and function 110%.

I believe Chris designed the ceramic ball lock-up of the umnumzaan to reduce wear and to prevent having to re-heat treat the lock, which can happen with the sebenza. When the sebenza lock is heat treated, carbids remain on the lock face. Over many years of opening and closing, this will wear as its basically titanium rubbing against titanium. Some never wear, seems to depend on the individual sebenza. With the umnumzaan, you have the blade tang, then the face of the ceramic ball. The ceramic ball contacts the blade, not the lockbar end like the sebenza. This design eliminates the need for a re-heat treat of a lock. The ball also sits to the inside slightly also maintaining the 75%+ lock-up. The sebenza over time, will increase in lockup % eventually touching the opposite slab. With the zaan lock-up design, this is eliminated. The design of the umnumzaan is an improvement over the sebenza in many ways.

Chris explained in depth the design of the umnumzaan on this forum when questions arose. I urge you to try an umnumzaan, you will not be disappointed. I would not have 3 of them if I felt they were unsafe in any way. Should Chris come out with even more different designs for the umnumzaan blades/scales, I will have one of those too.

 

[Cynic2701]

As nyefmaker says, the Umnumzaan lockbar design is superior to the Sebenza's.

Ceramic materials have extremely high compressional strengths, and only diamonds and a few extremely exotic materials can boast a higher strength. To give an example, the machines that calculate HRC values use a 120 degree diamond cone to measure hardness--the HRC of the ceramic ball used on the Umnumzaan would probably be difficult to calculate due to nature of ceramics.

The Sebenza, despite having a lock-bar face that is flush with the blade tang, still exerts more force on the point furthest from the pivot pin than anywhere else on the contact face. To conceptualize this, take a piece of play-do and a circular lever, and exert force into the play-do. The lever will indent deepest at the point furthest from the pivot point.

The Umnumzaan's lock-bar design is ingenious for more reasons than simple issues of wear. It takes into account the fact that the majority of the force that the lock-bar face will be put under will be at a single point. By using a material with much higher compressional strength than titanium or steel, Chris Reeve has advanced the frame-lock design to, basically, the furthest it can go lock-bar-face-wise.

On a side note, the O-rings have essentially zero effect on lock-up. They only affect how quietly the knife opens.

 

[balance123]

None of this makes the choice easy (between the WC and standard Zaan) - Really like the look of each and get how owning the three on the OP makes complete sense.
I suppose I'll start with the WC simply because they are a limited edition and move on from there. This CRK thing is definitely addictive. Have bought two Mnandis, a small Sebenza Tanto and a Mountaineer in the past month. Apart from my Carter knives and one or two gold series Benchmades, everything is getting sold off as they do not come close to the aesthetics and precision of CRK's catalogue, -- Amazing stuff.

 

[MiG Angel]

You gents wouldn't happen to know if the Star-tac will feature S35VN anytime soon would you?

 

[김원진]

nope, not anytime soon. me and a few others called before. the answer i got was around fall winter this year. Someone else said they told them maybe around summer, but being that it's already summer, and no one has gotten any definite answers, seems they're still trying to sell old stock. I'd be willing to bet fall.

Where are people getting the tanto version from ? loving that trio

 

[ForestRoamer]

The tanto version is an exclusive from True North Knives.

 

[Ankerson]

Last I heard, the other day when I talked to CRK on the phone it will be a few months before the switch over to S35VN.

 

[MiG Angel]

Last I heard, the other day when I talked to CRK on the phone it will be a few months before the switch over to S35VN.

Thank you 김원진 and Jim.

I think it might be time for another Umnumzaan. I'm digging the small evolutions CRK throws in there and am hopeful they will one day work away that hot spot the clip makes in the hand. I thought it might have only been my hand but I've read others mention the same complaint.

 

[Fferrell1]

Very nice collection! All you need is the Umnumzaan Insingo, and you'll have them all.... Oh wait, I might have dreamed that one up

Umnum Insingo... what a dream knife!!!