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Sebenza 31 Lock Rock?!

Discussion in 'Chris Reeve Knives' started by HikingIsLife, Mar 16, 2020.

  1. Murphjd25

    Murphjd25 Gold Member Gold Member

    Apr 27, 2016
    I haven’t handled a new 31 and it will probably be quite some time before I do, but this doesn’t concern me. I trust CRK, and none of their folders are designed to be fixed blades. I trust their locks with my life for what I use them for, and if I’m going to be stupid with a knife I will grab my Carothers. Neither of my Large 21s do this, they are like a bank vault. CRK makes good stuff. :)
  2. Ad58


    May 23, 2005
    Thank you, this was a very good explanation. I don't think it will affect a proper functioning of the knife. It's just flexing the lockbar a bit, which results in a bit play on the blade. And that only if you put pressure on the spine what will rarely happen in real life. So I don't think it's a real problem. I can imagine also that the lockbar will flex less when holding the knife.
    On the other hand: a $600,- knife should be flawless. For me this means I won't buy a 31 till CRK comes with a solution. In the mean time I will use my Zaan and large Inkosi.
    Heirphoto likes this.
  3. BilboBaggins

    BilboBaggins Gold Member Gold Member

    Feb 14, 2016
    Tried this on my 21 Insingo. Obviously, no ceramic ball involved. Zero flex at all. I'm sure the ball adds a pivot point that contributes to the movement. Probably wouldn't be a deal breaker for me if I were in the market for a 31.
    jackghobbies likes this.
  4. Dogdrawz

    Dogdrawz Gold Member Gold Member

    Aug 15, 2016
    My large Inkosi doesn't have this issue. No milled detent groove on the lock face. The detent ball did wear a slight groove on the lock face, maybe .001"-.003" dp.
  5. marrenmiller

    marrenmiller Basic Member Basic Member

    Apr 6, 2017
    I'm glad this is finally something people are realizing, as I've been doubted for saying my Umnumzaan and several XM-18s exhibit this, among other knives with similar lock geometry. This is probably not a serious concern, but it doesn't appear to be something that is easily solved.

    This has to do with where a frame lock engages on the blade tang relative to the pivot. Think of it this way: putting force on the blade's spine causes the blade to want to spin around the pivot barrel (some might call this a "moment" in engineering). To oppose this motion, the frame lock contacts the blade tang and applies a force to the tang in a direction perpendicular to the line between the point of contact and the center of the pivot. The reaction force on the lock is equal and points the opposite direction.

    This means that, depending on the lock geometry, some frame locks designs direct force along the length of the lockbar like a column, whereas some bend the lockbar like a beam. You might be able to visibly see the lock bar move up into the cutout between the lock bar and the rest of the frame, if you look carefully. The 31 in particular bends the lockbar up more than a lot of other knives because the ceramic ball shifts that contact point up much higher. Other knives have designs which do not bend the lockbar nearly as much (the Something Obscene Company J-Cape comes to mind here, as I cannot get mine to visibly flex in any way whatsoever, as the design of the knife directs the reaction force down along the lockbar almost entirely, rather than across the lockbar).

    Is this a design flaw? Not necessarily, unless the lockbar flexes so much that the blade tang can roll off the ceramic lock interface and slip. Is it an optimum design, though? I would say no, personally; other frame lock designs exist which do not exhibit this, and it seems an objectively weaker way to design a lockbar from an engineering perspective, though probably still well within the realm of acceptable for any reasonable use case. I think that the general layout of the knife means they can't change the lock design and engagement location much without a radical redesign, and the rest of the design is perfectly fine as-is.

    Hopefully this makes people realize that just because a company invented something, that doesn't necessarily mean they do that thing the best, especially after several decades of industry iteration.
    Last edited: Apr 1, 2020
    BTGuy, Heirphoto, insta9ves and 7 others like this.
  6. Officer's Match

    Officer's Match Gold Member Gold Member

    Jan 23, 2013
    And back in the pocket goes my 1st gen ball-groove Large Inkosi - just because. :) I have zero doubt the 31 is a spectacular knife; just the same I'm glad I kept my LI.
    aengina, BD_01 and Sharp & Fiery like this.
  7. bart1

    bart1 Gold Member Gold Member

    May 24, 2009
    This whole thing reminds me of a similar marketing evolution by Fender Guitars... Lots of forum members will relate. Fender had a stone winner with the Stratocaster guitar from 1954-1959 and decided to put out the Jazzmaster in 1959. It was pretty much a bust, but they did NOT discontinue the Stratocaster, now 60+ years later the Stratocaster is still considered among the best Electric Guitars ever.. With the Umnumzaan, and InKosi why was it necessary to discontinue a proven winner,and probably best seller for a new unproven model?
    matt009au, loon#r and Officer's Match like this.
  8. 353


    Feb 20, 2015
    I think it's pretty simple. Cutting down production time and cost, and thus gaining profit.

    Question is if CRK just shot their own foot with this move. This and the news that they no longer support 21 users with blades(is the blade that much different from the 31?!), have left me pretty cold.

    It will be very interesting to see what they do with this issue when they start up shop again.
  9. cbr1000


    Jan 31, 2013
    Thanks for bringing this up, made me think about their warranty. I have always been under the impression they have a lifetime warranty against manufacture defects. If you have a 21 with a defective blade will they not have blades to repair/replace?
  10. 353


    Feb 20, 2015
    Yes they will, until they have no more left.

    But they will only replace blades that has flaws from production.

    And what is the odds of them sending out a defective blade? I know there has been some examples of cracks from the press fit thumb lug and also some grinding issues(don't think they put a new blade on for that).

    So if you f up your 21 now you are indeed f ed and that's pretty f ed up IMO. :D
    Last edited: Apr 1, 2020
  11. Dogdrawz

    Dogdrawz Gold Member Gold Member

    Aug 15, 2016
    @razor-edge-knives might be one of many options if CRK drops the ball.
  12. kidcongo


    Jan 12, 2013
    No offence, but we see this spouted off all the time about CRK (literally all the time, for years, whenever they make the slightest change) but never any evidence to support this claim. It’s one of those “keyboard warrior” statements that looks clever to write, but isn’t really the case, based on my observations.

    If CRK was not passionate about anything but profits we’d have had their Chinese-made knives available at Target for years now. We don’t have this, because they are not purely profit driven.

    Why discontinue the Regular?
    Why discontinue the Classic?
    Why discontinue the 21?

    The reason for doing these things is the opposite of increasing profits. The reason to introduce new models and technologies is to keep the passion alive and the company moving forward. How completely dull would CRK be if the plan was to just pump out 21s for the next thousand years? I wouldn’t want to work there as an engineer or designer.

    Can you imagine if Ford said “the 2020 F150 is a great seller.....let’s just keep making that model forever”

    Thriving companies move forward and take chances to keep things interesting. It’s not always about the bottom line, contrary to popular belief.

    Just my opinion. YMMV
  13. 353


    Feb 20, 2015

    So honestly, from one “keyboard warrior” to another, dont you believe CRK will gain in both prodution numbers and general profit once they can steadily pump out 31's and not having to do hand fitting of the bladetang and also can skip the carburizing on the Ti lockbar face? It's a very simple question.

    I sure will miss the old lock. It's been doing pretty well, for 31 years!!

    As I said, it will be interesting to see what they come up with to make it better. Tim hinted on them already looking into it.
    Last edited: Apr 1, 2020
    insta9ves likes this.
  14. kidcongo


    Jan 12, 2013
    I have no idea of the labour divide between the operations. I simply doubt the move to the ball lock was profit driven. For all I know it takes more effort to tune the ceramic ball lock. It appears to be fitted and crimped by hand.
    steff27 likes this.
  15. Sharp & Fiery

    Sharp & Fiery Always Embellish Knifemaker / Craftsman / Service Provider

    May 14, 2012
    The entire reason for updating the 21 to the 31 is based on sales...

    Gotta keep the customers wanting the new thing...I know my 21 purchases slowed down over the last couple years and the market is flooded with 21’s. How do you increase sales? Make a new product that is hype!

    Ford doesnt make new designs to keep its employees happy...that is a naive assumption. Ford makes new products to keep sales moving. Everyone wants the newer truck.

    We as consumers get jaded and bored with the same old things. Companies must update their product lines to keep us interested...and believe me...they are watching their profit margins...thats why they are a business and still in business.

    I respect your opinions @kidcongo, and you have been here for a long time, but I have to agree to disagree.

    In business, it’s always about the bottom line.
  16. Officer's Match

    Officer's Match Gold Member Gold Member

    Jan 23, 2013
    If that is true about not supporting 21 blades after inventory dries up, then I am deeply disappointed in that decision by CRK. I have loved them as THE standard of high quality production folder companies, but that IMHO is a most regrettable business decision.
  17. Honed_Edge


    Feb 5, 2013
    We need to be clear about this blade replacement topic. I called them and asked about the situation weeks ago. But, you don't have to take my word for it. Well, at least not for much longer... CR is closed for a few weeks.

    I was told that warranty blades will be available for a long time. I doubt they know exactly how long. I guess they have a large enough stock to last a while at warranty replacement rates. That's the key to all this, warranty work. The only way to get a new blade is if it breaks or fails due to a manufacturing defect, thus a warranty claim. If a tip is broken, they will regrind it for you. However, if you cut into a live wire and melt a chunk out (ya, we saw the picture) then they will not help even if you throw money at them. I see both sides here... it's just hard not to side with me! I don't like this, but it's true for all discontinued models.

    While this applies to very few here, they also wont re etch damascus on any discontinued model.
    I was bummed to hear no more damascus blades were available should I be dumb enough to need one, then one final blow as I find out they wont even re etch my old blade when it fades over time.

    I still love them, carry them and likely will buy more of them in the future. I can gripe about many other things from many other companies. The moral of the story is.... don't buy CR models in the later half of the life cycle if you want solid support should anything wild happen. Get in there early. Go you 31 adopters!
    Sharp & Fiery and 353 like this.
  18. marter


    Jan 1, 2020
    In addition to no re-etch, they won't put double studs on a single stud damascus 21. Ask me how I know.
    matt009au and Honed_Edge like this.
  19. XtianAus

    XtianAus Gold Member Gold Member

    Mar 3, 2016
    The 31 was going to be my first high-end folder. After years of spending large amounts on high-end fixed blades, I wanted to try some high-end folders instead of just cheap(ish) beaters. But after reading all this, I am highly turned off. What a disappointment. I'll have to keep looking now on where to make a splurge into the high-end folder world..
    Forester_01 likes this.
  20. kidcongo


    Jan 12, 2013
    I agree with your points. I guess the obvious of wanting new models to keep customer demand high was wrapped up in my thinking as well. Ford might have been a bad example. My point comes from working for a small business myself that looks to innovate to meet future demand, and because we easily bore.
    Sharp & Fiery likes this.

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