Sebenza 31 Lock Rock?!

[sailfish]

A noteworthy point of interest I think worth mentioning: I can also get the lock bar to flex on my Hinderer XM-18.

 

[Sluggy]

I bought a small inkosi that has a little bit of up and down play and flex. If I wiggle blade up and down I can hear a tiny tick as I do it.

Is it worth it to send it to CrK to try and address or should I just live with it? I’d prefer the lockup be better but I also don’t mind if this is normal with the ceramic ball.

thanks

send it back ,

 

[kylemiller]

Reports in the FB group of new 31’s shipping with loctited screws. This matches my 31 experience where screws had to be “tuned”.

 

[rileybassman1]

Mine was a Large Micarta 31 drop point.

Ditto

 

[rileybassman1]

Reports in the FB group of new 31’s shipping with loctited screws. This matches my 31 experience where screws had to be “tuned”.

I didn’t have any on mine, however I did loctite my stop pin screws as I feel they really set the action... can be very tight or very loose depending on their tightness.

 

[Sharp & Fiery]

I didn’t have any on mine, however I did loctite my stop pin screws as I feel they really set the action... can be very tight or very loose depending on their tightness.

No factory loctite on my 31 when it came back all fixed up either.

 

[sailfish]

So I'm guessing the Insingo CF 21 was somewhat of a fluke? Maybe it's considered a working specimen? Of course all this goes right out the window when you're talking about exclusives.

With the exclusives they probably wanted to keep the market broader. The BHQ exclusive offered an insingo and tanto as well. Carbon fiber is expensive and perceived as luxurious but it's an incredibly strong, lightweight and nearly impervious functional material, so CRK probably didn't look at it in the same regard they do the wood. They likely viewed it more as a user too and this is evident where if you look at the KA Sebenza, the entire lock side is blasted, unlike the wood or BHQ that is polished. The drop point is also stonewashed unlike the former two's polished. My KA carbon fiber 21 insingo has actually probably been my hardest worked knife of all my Sebenzas, including the micarta and plain. Though this is most likely just a result of it being my favorite and seeing the most pocket time.

I just thought of something else that backs up the idea that the CF scale model was intended to be more of a user. Wood inlay models, the BHQ inlay models, graphic models, and anything with a damascus blade (even plain scales) include a leather slip in the box. The CF scale with S35 models do not.

 

[ChazzyP]

So, I've read this thread through in several sittings over the last few months, but have been reluctant to add my two cents worth until I actually handled (read, owned) a 31, though some impressions I've had are more general and aren't related to specific experience with that model. I'll try to brief, though I suspect this will run on, as I list my thoughts in no particular order.

Firstly, while this thread topic lends itself to volatility, the discourse here has remained largely civil, which is much appreciated and far more informative than a lot of posturing and finger-pointing.

I'm so pleased for our friend Sharp & Fiery that he got his knife back from CRK warranty service with all its problems resolved. He expected, as did I, that they'd get it right, and it's satisfying that they did.

I've thought all along that the problems that some 31's exhibited were QC-based and not design-based and the evidence seems to suggest just that, as there seems to be a lack of issues with later models (such as mine from August 17, '20) as opposed to those built in earlier runs. Some of this may just reflect an inevitable change in culture as the company leadership transitioned over time. I can just imagine Chris stalking from workbench to workbench, yelling at those responsible for QC when knives came back for warranty issues, and the inevitable relaxation with possible slippage that would might occur when that sort of pressure became absent. Also, there are enough changes to what's now the lone Sebenza platform that it's close to being a new model and as such there would be bugs to work out in its milling and production.

The thing with the stop pin does seem significant. Mine was LocTited and when re-assembling I found it necessary to leave it just a taste loose to keep the action from being overly tight. Time will tell whether it will need thread locker, though I suspect it likely won't. This is reminiscent of my experience with the 25, finding that a two-screw/fixed stop pin very much negated the advantage of an adjustable pivot and that the pin needed to be set to match the action desired. The switch to the Inkosi pattern introduced the floating stop pin and I'm both a big fan of that design and wonder why that wasn't included in the improvements featured on the 31.

As to the big question of "vertical play" or "lockbar flex", I held my new 31 in two hands, pinching blade and handle with thumbs and forefingers near the pivot, blade tip and handle butt against my outer palms, with remaining fingers out of harm's way, and flexed as hard as I could with no discernible movement. I did the same with my other ceramic ball CRKs--StarTac 'Zaan, Starbenza 25, and Inkosi's--with similar results.

I had resisted doing the table-top test for months on those three models mentioned in the last sentence as it seemed to have little relevance to how one might actually use a knife as well as being somewhat akin to spine-whacking, a trial I find to express idiocy at it's finest. Anyway, with my 31 now in hand, I found I could resist no longer and tried the TTT with all those mentioned and got pretty much the same results--maybe 2 or 3 hundredths of movement under great pressure. All the knives are rock-solid in use, though, and that little bit of movement under extreme and unnatural duress doesn't bother me in the least.

Finally, as to "lockbar flex", I'm wondering if that's really what's going on here or if that slight movement exposed on the table's edge is the ceramic ball rolling just a little until there's enough pressure applied 'til friction makes it stop.

The bottom line here is that I really don't care now that I have my 31 and it's every bit as solid and well-loved as my numerous other CRKs. I knew this would end up being a wall of text--much more than two cents worth in volume, though likely not value--having held back for so long, but because it didn't happen without pics, here's my 31 and 25 on the day I received the former...

...and here's the 31 all tricked out as it seems to be with me most all the time lately.

 

[Jsega51]

I like it ChazzyP . Good write up

 

[BD_01]

Amen on the stop pin. Although, perhaps I’m blind to the reason it wouldn’t have worked on the 31.

I’m glad it seems kinks are working their way out of the model. I’m sure there’s one in my future at some point.

Off topic, but I harbor the fantasy that, as a new model, the door will be open for reissue of some of the more popular 21 CGG’s. (Hey, a guy can dream, right?)

 

[sailfish]

I always thought the shape of the body screw head and the scale hole recess compressed and worked to keep the screws tight? Gotta wonder why the new stop pin would have any affect on that.

 

[ChazzyP]

I always thought the shape of the body screw head and the scale hole recess compressed and worked to keep the screws tight? Gotta wonder why the new stop pin would have any affect on that.

If you're responding to my comment about stop the pin screw possibly backing out, that's because I couldn't tighten it down fully enough to gall into the recess in the Ti slab when setting the action. The distance from shoulder to shoulder on the 31's stop pin has to be exactly correct relative to the length of the pivot bushing, taking into account the washers and lube plus just enough nano-space to allow for proper action. If it's too long, then the action isn't right and it's impractical to tune the knife by shortening the pin shoulders. Getting it dialed in is such a fine adjustment that it makes sense for the pin tolerance to center toward the too short side and then be able to either take the washers down slightly or back the stop pin screws out a taste and LocTite them, freezing the action where CRK wants it when it leaves their shop.

The next time I open my 31, I'll polish my washers on the old strop I use for that, tighten the stop pin screws all the way down when reassembling, then try the action. If it needs to be freed up a little more I'll open the knife back up, take the washers down ever so slightly (a couple thousandths is all they usually need), and try it again.

 

[brownshoe]

So, I've read this thread through in several sittings over the last few months, but have been reluctant to add my two cents worth until I actually handled (read, owned) a 31, though some impressions I've had are more general and aren't related to specific experience with that model. I'll try to brief, though I suspect this will run on, as I list my thoughts in no particular order.

Firstly, while this thread topic lends itself to volatility, the discourse here has remained largely civil, which is much appreciated and far more informative than a lot of posturing and finger-pointing.

I'm so pleased for our friend Sharp & Fiery that he got his knife back from CRK warranty service with all its problems resolved. He expected, as did I, that they'd get it right, and it's satisfying that they did.

I've thought all along that the problems that some 31's exhibited were QC-based and not design-based and the evidence seems to suggest just that, as there seems to be a lack of issues with later models (such as mine from August 17, '20) as opposed to those built in earlier runs. Some of this may just reflect an inevitable change in culture as the company leadership transitioned over time. I can just imagine Chris stalking from workbench to workbench, yelling at those responsible for QC when knives came back for warranty issues, and the inevitable relaxation with possible slippage that would might occur when that sort of pressure became absent. Also, there are enough changes to what's now the lone Sebenza platform that it's close to being a new model and as such there would be bugs to work out in its milling and production.

The thing with the stop pin does seem significant. Mine was LocTited and when re-assembling I found it necessary to leave it just a taste loose to keep the action from being overly tight. Time will tell whether it will need thread locker, though I suspect it likely won't. This is reminiscent of my experience with the 25, finding that a two-screw/fixed stop pin very much negated the advantage of an adjustable pivot and that the pin needed to be set to match the action desired. The switch to the Inkosi pattern introduced the floating stop pin and I'm both a big fan of that design and wonder why that wasn't included in the improvements featured on the 31.

As to the big question of "vertical play" or "lockbar flex", I held my new 31 in two hands, pinching blade and handle with thumbs and forefingers near the pivot, blade tip and handle butt against my outer palms, with remaining fingers out of harm's way, and flexed as hard as I could with no discernible movement. I did the same with my other ceramic ball CRKs--StarTac 'Zaan, Starbenza 25, and Inkosi's--with similar results.

I had resisted doing the table-top test for months on those three models mentioned in the last sentence as it seemed to have little relevance to how one might actually use a knife as well as being somewhat akin to spine-whacking, a trial I find to express idiocy at it's finest. Anyway, with my 31 now in hand, I found I could resist no longer and tried the TTT with all those mentioned and got pretty much the same results--maybe 2 or 3 hundredths of movement under great pressure. All the knives are rock-solid in use, though, and that little bit of movement under extreme and unnatural duress doesn't bother me in the least.

Finally, as to "lockbar flex", I'm wondering if that's really what's going on here or if that slight movement exposed on the table's edge is the ceramic ball rolling just a little until there's enough pressure applied 'til friction makes it stop.

The bottom line here is that I really don't care now that I have my 31 and it's every bit as solid and well-loved as my numerous other CRKs. I knew this would end up being a wall of text--much more than two cents worth in volume, though likely not value--having held back for so long, but because it didn't happen without pics, here's my 31 and 25 on the day I received the former...

...and here's the 31 all tricked out as it seems to be with me most all the time lately.

Nice review. Which model would you keep if you couul keep only one?

 

[ChazzyP]

Nice review. Which model would you keep if you couul keep only one?

That's like asking me to pick a favorite from my three sons. I tell each of them "You're my favorite" and when asked why I say "Because you're the only one here." My favorite CRK is the one I have in my pocket. To put it another way, my ideal would be a knife with the pure simplicity of the 21's bushing pivot and plain carburized lockbar; the large radius grind and floating stop pin of the Inkosi; and the inlays of the 31.

 

[Boinkman]

If you're responding to my comment about stop the pin screw possibly backing out, that's because I couldn't tighten it down fully enough to gall into the recess in the Ti slab when setting the action. The distance from shoulder to shoulder on the 31's stop pin has to be exactly correct relative to the length of the pivot bushing, taking into account the washers and lube plus just enough nano-space to allow for proper action. If it's too long, then the action isn't right and it's impractical to tune the knife by shortening the pin shoulders. Getting it dialed in is such a fine adjustment that it makes sense for the pin tolerance to center toward the too short side and then be able to either take the washers down slightly or back the stop pin screws out a taste and LocTite them, freezing the action where CRK wants it when it leaves their shop.

The next time I open my 31, I'll polish my washers on the old strop I use for that, tighten the stop pin screws all the way down when reassembling, then try the action. If it needs to be freed up a little more I'll open the knife back up, take the washers down ever so slightly (a couple thousandths is all they usually need), and try it again.

I'm thoroughly impressed with your understanding of knife mechanics and ability to communicate it. I've found over the years that the action on a knife is greatly dependant on the tolerances matching on the pivot, stop pin, and standoffs. A lot of production knives don't get this dialed in perfectly at the factory. I just wish I knew this back when I first got into knives. I would just unload knives that didn't make the cut instead of solving the problem.

 

[jackghobbies]

I'm thoroughly impressed with your understanding of knife mechanics and ability to communicate it. I've found over the years that the action on a knife is greatly dependant on the tolerances matching on the pivot, stop pin, and standoffs. A lot of production knives don't get this dialed in perfectly at the factory. I just wish I knew this back when I first got into knives. I would just unload knives that didn't make the cut instead of solving the problem.

I'm on my second Sebenza 31 that has the issue of the pivot screw backing out. Similar issue to the hardened stop pin issue. I suspect vibrations and screw thread issues as part of the root cause.
It's on the way back to CRK via BladeHQ. Sad to buy a high end knife with these issues.
CRK now includes loctite in the box which didn't solve my issue but also noting here for everyone who gave feedback on not using loctite as the 21/31 was by design not recommended.
Maybe consider designing for intolerance (loctite is a clear indication of an attempt to mitigate) instead of the laser focus on tight tolerances. Just a thought.

 

[BD_01]

I'm on my second Sebenza 31 that has the issue of the pivot screw backing out. Similar issue to the hardened stop pin issue. I suspect vibrations and screw thread issues as part of the root cause.
It's on the way back to CRK via BladeHQ. Sad to buy a high end knife with these issues.
CRK now includes loctite in the box which didn't solve my issue but also noting here for everyone who gave feedback on not using loctite as the 21/31 was by design not recommended.
Maybe consider designing for intolerance (loctite is a clear indication of an attempt to mitigate) instead of the laser focus on tight tolerances. Just a thought.

Just out if curiosity, was the screw backing out the only issue with the knife that’s going back?

 

[jackghobbies]

Just out if curiosity, was the screw backing out the only issue with the knife that’s going back?

Yeah. BHQ didn't wan't to do a refund after I only had it for a 1-2 weeks because they said there were some scratches on the blade tang. hrmm, yeah, I opened/closed it but that is all. But they couldn't show a photo of the "scratches". BHQ is sending it to CRK. Makes me sad because I love everything <else> about the 31.

 

[bgrif119]

Hey guys! Brand new to forum. First post, and first CRK. So I just received my small Sebenza 31 in the mail today. First thing I did out of the box was check the blade play. It had lock rock. The born date was November 17, 2020. I don’t know if I was just excepting a really tight knife or not, but the blade play seems to be excessive. Side to side seems fine though. I contacted CRK and I am waiting for a reply.

 

[sailfish]

Hey guys! Brand new to forum. First post, and first CRK. So I just received my small Sebenza 31 in the mail today. First thing I did out of the box was check the blade play. It had lock rock. The born date was November 17, 2020. I don’t know if I was just excepting a really tight knife or not, but the blade play seems to be excessive. Side to side seems fine though. I contacted CRK and I am waiting for a reply.

Lock rock or lock bar flex?