Off-center hex sockets on Sebenza 21- is this science??? Another CRK trade secret?

kidcongo

kidcongo

Joined
Jan 12, 2013
Messages
3,195
This has been mentioned often here on the forum, and I have also read that CRK says it is on purpose on some old thread.

At Issue: The female sleeve screws, all of the fasteners on my 25, the fasteners on my old Umnum are all perfect in every way. On the Sebenza 21's the male hex screws for the slabs have the hex socket slightly offset to one side. The male screw for the pocket clip has it's hex is perfectly centered. Also it is not just a few of them. I own seven Sebenza 21's and the mail screws for the slabs and pivot have an off-center hex on all of them. It is less apparent on my three small 21's, but there are still not centered.

So......my question:

If CRK can make (or buy) perfectly centered female sleeve screws, pocket clip screws, 25 pivot and button head screws, and even make something as complicated as the old Umnumzaan pivot screw, what is the reason that the 21 male screws are offset? It could be assumed they could be made centered if that was the plan.

Is it something to do with making them bite into the Titanium to lock them (since no locktite is applied)?
Is it to somehow change the torque angle on the hex driver and prevent stripping the screws?
(or) Did I magically buy seven 21's (21 screws total) that all have defective screws?

We know that some of the features of the Sebenza 21 are not necessarily advertised in literature, and I recall a forum member saying in a post that they called CRK and were told the off-center screws "are supposed to be that way".

Anyways......I am not bothered by this, but find it curious and am wondering if anyone has any thought on the subject
 
Hrmm...I cannot think of one advantage to doing this.. Beit leverage or otherwise, the limiting factor in my opinion is the size of the hex.. Apply too much force, regardless of any cam action and it's going to strip.

Will give it some more thought and check my collection, but it is a bit odd to have all of your 21's off center.. How much off center out of curiosity?

As always, good observation!
 
I have four 25s, three 'Zaans and one 21, and they are all perfectly centered on both sides.

I assume you are talking about the hole you place the Allen wrench into being off-center, is that it Cody?
 
It seems to me, they had trouble sourceing decent screws for awhile. Are all of your knives close to the same age?
 
jmclfrsh said:
I have four 25s, three 'Zaans and one 21, and they are all perfectly centered on both sides.

I assume you are talking about the hole you place the Allen wrench into being off-center, is that it Cody?
Click to expand...

Yes I do mean the hex hole in the screw head being offset in the screw head, not the screw itself being offset in its hole.

Respectfully the 25s and Ummums are not being discussed. They use different screws and loctite (which is one of my loose theories) The only screws in question are the male screws on the 21.

Has anyone else noticed this, or am I alone?
 
Last edited:
pvicenzi said:
It seems to me, they had trouble sourceing decent screws for awhile. Are all of your knives close to the same age?
Click to expand...

The knives span about 4 years. I hear what you are saying, the only thing that is weird is why would it only be the male screws for the non-locking slab, and not the pocket clip screws, or the female screws. You would think they would all be bogus.

Anyways I'll post some pics when I get a chance. As mentioned, I am not bothered by this, but it is strange to me if its just because they are 'cheap'. The screws on even cheap dollar-store Chinese knives typically have centered fasteners.

Hopefully someone will confirm I'm not going cross-eyed or insane.
 
Understood. My sole large micarta 21 is a late 2013 or early '14, and they are centered on both sides.

Others?
 
Just finished checking all of mine-

Small plain 21,...Looks off center
Large Plain Micarta Insingo..Looks off center
Snakewood Classic 2000..Centered
Large Micarta Serrated..Centered
Umnumzaan..Centered
25..Centered
Large Starbenza..Centered
 
When I got my first Seb the off centred male screws were the first thing I noticed, I've seen it before so wasn't overly surprised.

If you get a loupe you will notice these off centre screws are cast (smoother shiny surface with little dimples) whilst the centred female screws are turned (circular cuts on the head). My 2014 insingo has turned male screws so it appears they have made a change in suppliers or specifications.
 
Jimbo75 said:
When I got my first Seb the off centred male screws were the first thing I noticed, I've seen it before so wasn't overly surprised.

If you get a loupe you will notice these off centre screws are cast (smoother shiny surface with little dimples) whilst the centred female screws are turned (circular cuts on the head). My 2014 insingo has turned male screws so it appears they have made a change in suppliers or specifications.
Click to expand...


The "female" portions are made by CRK..

The male screws are sourced..Not an easy thing to find when you are after quality and a specific size screw with the proper taper.
 
bhyde said:
The "female" portions are made by CRK..

The male screws are sourced..Not an easy thing to find when you are after quality and a specific size screw with the proper taper.
Click to expand...


If my 2014 Insingo is anything to go by, it might suggest that CRK are now making the male screws also.
 
I've never noticed this on any of my CRK knives. But my guess for this happening would be that a large batch of screws was ordered that may have been made a little off. Somewhere along the line the decision was made to just use them up rather than scrap them.
 
I've had sebenza's with off center screws before, looks sloppy. I didn't keep those.
 
A screw, in general, by necessity having rotational symmetry, I'm guessing that the hex opening isn't off-center, but that the head could be slightly asymmetric relative to the opening and the screw part itself. Also, on my knives, there can be an impression of asymmetry depending on the way the light strikes the screw heads. I have not measured the screws for any offset, but I think that these days you'd have to go to the lowest of the low vendors to source substandard screws. Can't imagine CR doing that for a penny-a-dozen item.
 
Well,

Maybe it is just duff screws. Seems a high percentage in my collection. Maybe this photo does justice (it's a hard thing to photograph)

DSCF7369_zpsnf5rqmlx.jpg
 
You must log in or register to reply here.
Back
Top