31 Screws Keep Backing Out

[Jsega51]

I have a 21 for many years, it doesn't need loktite. Needing loktite means you can not put it back together with only one wrench, like a 21, with the 31 you need glue too. Chris was proud of the Sebenza being designed to not need glue. He used to post here.

I think you’re confused. Just because some people need it for the 31, doesn’t mean everyone will and CRK isn’t saying that it requires it. My 31 came with no such documentation.

There’s plenty of people that needed it for their 21, and again, not everyone did. So just to be clear, you have no first hand experience with it happening on the 31? I haven’t had issues with no loctite being on the screws, they pop just fine when taking it apart and don’t move.

I can also take mine apart and put it back together with the one wrench they supplied. Sounds to me like the knife is working just fine.

 

[XL883N]

My 3 31s didn't come with any locktite. Screws on my 31s and 21s tend to back out if I don't tighten them enough to begin with. I do flick my knives a lot and that probably has something to do with it.

 

[TRfromMT]

The 31 is nothing if not polarizing. There is some crazy impression now that the screws are just flying out! If you happen to ever need to do a full strip and rebuild, while out in the bush, you are now screwed (pun intended) without locktite and only one wrench? This is insultingly stupid. The screws will be fine for however long you may be out. Get on with it.

(and by the way, to suggest the Sebenza is field serviceable is a real stretch. Who will ever take their allen key's along when in the field just in case they need to fix their knife for some reason? But I digress.)

I absolutely understand that guys see the addition of the locktite in the box as a bit of a bandaid solution now, after the fact. Fair enough.

But locktite is absolutely an acceptable, aerospace engineering grade solution to retaining screws. Had it been included in the very first box sold this thread would not exist.

Product support involves these kinds of solutions sometimes. If guys called up CRK HQ and said, "Hey, by 31 came without locktite, could you send me some?" I bet they'd comp you a tube.

 

[Jsega51]

TRfromMT exactly. Field servicing would have me much more worried about dropping a screw vs worrying about it backing out after opening and closing it a crap ton of times.

Which brings up another point. The reported screws backing out have only been the lock bar screws (same issue has been reported by 21 owners also). To service your knife, there’s no need to take those out. You only have to take the pivot screw and bushing out to remove the blade.

So yep, the 31 is field serviceable with just a wrench.

Nope wait, @brownshoe also forgets that it’s not just a wrench that would be needed. He would need to carry his tube of grease also for his 21.

 

[Dcdavis]

I think you’re confused. Just because some people need it for the 31, doesn’t mean everyone will and CRK isn’t saying that it requires it. My 31 came with no such documentation.

There’s plenty of people that needed it for their 21, and again, not everyone did. So just to be clear, you have no first hand experience with it happening on the 31? I haven’t had issues with no loctite being on the screws, they pop just fine when taking it apart and don’t move.

I can also take mine apart and put it back together with the one wrench they supplied. Sounds to me like the knife is working just fine.

It happens from time to time on my 21s also. Happened today at work, tightened it back up no big deal. I can tell when the action gets extremely free feeling

 

[sailfish]

Just checked all the screws on my 31 including the back of the stop pin and I'm happy to report they were all still snug. The design of the recess seems to do a good job at holding the screws on Sebenzas. I've only had a screw back off once and that was on my first 21's pivot while it was still breaking in. Never happened again though. I might not've tightened it enough too. With the work I use mine for they get gunked up and dusty so I also tear down and reassemble mine for cleaning fairly regularly too though.

As for the 31 not being Chris' knife I don't know if that's entirely fair to say. There's nothing completely new or original about the design of the 31; every aspect of it is a feature Chris has already designed and used one his other knives. It was just a matter of time before they were implemented on the Sebenza.

 

[DanG]

As for the 31 not being Chris' knife I don't know if that's entirely fair to say. There's nothing completely new or original about the design of the 31; every aspect of it is a feature Chris has already designed and used one his other knives.

At least two essential "aspects" of the 31 are "new" and have obviously not been designed by him: The stop pin and the lock geometry. And that is exactly where the dog is buried with the 31.

 

[sailfish]

At least two essential "aspects" of the 31 are "new" and have obviously not been designed by him: The stop pin and the lock geometry. And that is exactly where the dog is buried with the 31.

Explain what you mean because the Umnumnzaan incorporated the ceramic interface years ago and the Inkosi a back-threaded stop pin.

 

[DanG]

Explain what you mean because the Umnumnzaan incorporated the ceramic interface years ago and the Inkosi a back-threaded stop pin.

If you look closely there are almost no similarities between the knives except for a ceramic locking ball. The Umnumzaan has a structurally different lock bar, the ceramic ball sits in a different location in relation to the pivot and engages the blade tang in a different place. Same for the Inkosi. Which is to say that the locking geometry on the Umnumzaan and the Inkosi (and the 21) are completely different from the 31.

And with regards to the stop pin the Inkosi has a floating one of non-hardened steel screwed to the lock side scale. The 21 has a hardened stop pin sleeve fitting tightly over the female screw. Both designs soak up shock very well. The 31 though has an integral, hardened through stop pin that is hard on the threading of the male screws and doesn't soak up shock very well. Combine that with a not so optimal locking geometry and you realize that there is more to the 31 drama than meets the eye. There's something going on that needs to be addressed.

 

[Jsega51]

The 31 though has an integral, hardened through stop pin that is hard on the threading of the male screws and doesn't soak up shock very well. Combine that with a not so optimal locking geometry and you realize that there is more to the 31 drama than meets the eye. There's something going on that needs to be addressed.

How do these changes affect the knife, or operation, assuming that it’s being used in what would generally be considered a normal manner? In comparing my 31 and 21, the changes are almost imperceivable (other than lock bar tension being increased on the 31). Both are smooth and have no issues. Has your 31 failed?

 

[Bear4142]

I've been away for awhile and did not realize this thread turned into another argument about the 31 and CRK.
I was simply looking to see if my issues were irregular or the norm on the 31 ( looks like a combo of both).
There's plenty of other threads discussing the 31 so locking this one down.