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Are ball bearing pivots just a marketing gimmick?

Discussion in 'General Knife Discussion' started by letsurf, Aug 22, 2019.

  1. Sharp & Fiery

    Sharp & Fiery Always Embellish Knifemaker / Craftsman / Service Provider

    May 14, 2012
    “Going from folder to folder with bushings is a compromise”

    Did you mean “washers” not bushings?
  2. marrenmiller

    marrenmiller Basic Member Basic Member

    Apr 6, 2017
    A folding knife is a tool used for cutting, not for prying edge wise against your bearing suspension pivot system. Knives are not made to be as strong as possible (and in fact that's a pursuit that's antithetical to blade geometry), but it's a fact that one of a folding knife's primary functions is to fold open and closed. Properly implemented ball bearings do that easier, if only slightly, than bushings/washers. Meanwhile, they are only potentially an issue in use cases that are distinctly not in the scope of knife use.

    I am an actual licensed professional mechanical engineer, and in my circle of friends we have a joke about people that always want to make something stronger and stronger: "What about 3 bolts? Well, what about 4? How about 5? 6?" At a certain point, you no longer need more strength or durability. The "technical reality" is that engineers design things to be as strong as they need to be, because any more so is unnecessary cost, added weight and/or complexity, and at times at odds with with intended use of the item.

    If your philosophy really is that a folding knife should be as strong as possible, then I hope you also don't own any frame or liner locks before you start pinpointing ball bearings as an unnecessarily weak link in folding knife design. Ball bearing failure generally won't result in a knife closing on your hand.

    Edit: not to discount personal opinion or anything, but just the fact that there are a ton of people here who don't like cold steel's triad lock knives would indicate that strength isn't everything people consider in functional cutting tools. With that being said, I also love those kinds of knives.
    Last edited: Aug 28, 2019
    Sharp & Fiery and 357snubnose like this.
  3. marrenmiller

    marrenmiller Basic Member Basic Member

    Apr 6, 2017
    Washers are a form of bushing
  4. Sharp & Fiery

    Sharp & Fiery Always Embellish Knifemaker / Craftsman / Service Provider

    May 14, 2012
    So a Crk Sebenza has three bushings then...
    I learn something new everyday.

    marrenmiller likes this.
  5. marrenmiller

    marrenmiller Basic Member Basic Member

    Apr 6, 2017
    Actually, I think I misspoke. A bushing is a form of bearing for radial loads (like the bushing pivot). A washer should properly be called a thrust bearing. I've just heard the term "bushing" being (evidently incorrectly) used so often to describe washers.
    Sharp & Fiery likes this.
  6. Sharp & Fiery

    Sharp & Fiery Always Embellish Knifemaker / Craftsman / Service Provider

    May 14, 2012
    This I agree with! :)
    Im so tired today, i couldnt even pull “thrust bearings” out of my brain. Glad one of us could. Lol.
    Last edited: Aug 28, 2019
    marrenmiller likes this.
  7. kefefs

    kefefs Gold Member Gold Member

    Feb 24, 2019
    No, it's not a gimmick. When done well they can make for an incredible action. I've owned $30 ball bearing folders with better actions than $150 ones with PB washers.

    This is my $35 CH Toucans on bearings. It has one of the best actions I've ever felt and drops shut like a champ.

  8. uraninite


    Aug 21, 2019
    Gimmick to me. Hard(er) for users to maintain, extra moving parts on a device that should follow KISS (to some extent) and add to the cost without adding to the functionality. On the other hand, they add to the fun of the knife. Autos could be called a gimmick too, for the same reasons, but I think most of us here can´t help but grin when we pop open a fast snappy auto. Same goes for flipping open a super smooth ball bearing flipper. At some point a knife starts to transcend its tool roots and becomes art.
  9. sharp_edge

    sharp_edge Gold Member Gold Member

    Jul 30, 2015
    I have a ZT 0562 currently being serviced at KAI warranty department. It was a smooth folder back to some time ago. Then the action gradually deteriorated, to the point that it can no longer reliably be flipped open fully. The detent ball has become obviously flat, though I am not sure if it is the reason. Another thing is a deeper bearing track has been formed on the ti side of the pivot. I dont know if the track is so deep that the plastic cage begins to contact the ti scale. Granted this is one of the oldest flippers for me and also perhaps the most flipped (thousands times), and I have no idea how many times its previous owner(s) flipped it.

    I am interested in learning how KAI fixes the issue or if they will successfully fix it.
    Last edited: Aug 29, 2019
    kreole likes this.
  10. robgmn


    Oct 30, 2015
    You missed my pint almost entirely. And that's OK. I at least hope you DID catch that I know even "weakened" tools are rarely used to a point that approaches their mechanical limits.

    But, I'll ask you to clarify "it's a fact that one of a folding knife's primary functions is to fold open and closed".
    Making a knife fold is a compromise of mechanical integrity. It adds convenience at the sake of strength. It's a "function" per se, but how is it "primary"? It adds nothing to the cutting ability of the knife. Cutting being the only "true" function of a knife.

    Again, I'm talking the "big picture" discussion of the main thread topic.
    I DO understand that reality is different (read back to my mention of carbon-fibre handlebars on my bike).
  11. CPP


    Sep 8, 2014
    If a knife is updated with bearings after having working perfectly fine without I'd say it's likely a gimmick. In general, however, bearings are definitely a progression. The purpose of any opening mechanism is obviously to open the knife reliably and safely so if bearings make that mechanism more effective and efficient then it's definitely an improvement–especially on knives with flippers. To digress a bit, having bearings on knives without flippers doesn't seem to add much to the opening mechanism. Based on my reasoning I prefer flippers to have bearings and non-flippers to have bushings. I have a knife that shall remain nameless that has an updated detent system and washers and opens using a thumb disk but it works too well: it's as though my thumb can't keep up with the blade as it's opening resulting in cuts on my thumb. So were that knife to have bearings I might not have a thumb.
    marrenmiller likes this.
  12. marrenmiller

    marrenmiller Basic Member Basic Member

    Apr 6, 2017
    At the risk of sounding rude, are you even trying to make a point? I am perplexed at to what you are trying to convey here, despite you writing that it's just "philosophy". You're stating that you believe you understand how design actually works, but you seemingly contradict that statement by not grasping the concept that something isn't a gimmick if it provides value to people.

    The main thread topic is if ball bearing pivots are a marketing gimmick. People have presented definitive reasons why they believe ball bearing pivots offer small but in some cases meaningful improvements for the folding knife world, and your response seems to be: "Folding open and closed isn't something knives need to do, and ball bearing pivots are bad because it's too much of a compromise along the entirely subjective sliding scale I've laid out." I mean, how does anyone even reason with that kind of logic? Clearly people have different use cases for folding knives than I, but I wouldn't go around calling the knives I don't like gimmicky because I don't personally have a use for them.
    Last edited: Aug 29, 2019
  13. Basp2005


    Dec 6, 2015
    I don't want anything to do with loose bearings. If a knife has that "feature" I'm not buying it. Captured bearings are fine, and fun. But a dedicated "hard use" knife should have phosphor bronze washers. Easier to clean and maintain with less chance of gunk getting in. Ymmv.
  14. soc_monki

    soc_monki Basic Member Basic Member

    Apr 5, 2019
    Harder to maintain? Caged bearings are no harder to maintain than pb washers. The knives are assembled the same, so it's basically the same level of difficulty. Now loose bearings... I don't think I'll buy a knife with loose bearings but if I did it would add just a little complexity. But I'd prefer caged.

    I don't think they are a gimmick, I just think they are a different option. I like my bearings (0562, 0470, Amalgam...) but I like my washers too (manix, PM2, Para 3...). There are a ton of choices so if someone doesn't like bearings then there are other knives to buy. I like both, and will put both through the same tasks. They all have a lifetime warranty so if something happens and the knife fails I'll use that warranty. However I don't try to chop down trees with my knives so I doubt I'll have a failure!

    I'll continue to buy both.
    marrenmiller and uraninite like this.
  15. robgmn


    Oct 30, 2015
    Reread my posts and you might get a better understanding.
    "Marketing gimmick"? Probably not. More like "unnecessary add-on that doesn't truly enhance the job a knife should do", which is to CUT. Put a gold handle inlaid with diamonds on your dull kitchen knife. It's "enhanced". Have fun prepping dinner with it.

    Physics, mechanics, engineering, are not "subjective". They are fact-based.
    You can SAY I'm wrong in my statements. You may BELIEVE I'm wrong in my statements.
    But, you cannot prove it, because my statements are based in fact and not opinion. Some people truly dislike that. I find it odd, but we're all unique and that ain;t gonna' change.

    .I'm not a knifemaker, but I've made a knife. I stuck to the very basic principles of full-tang, robust shape, very hard wood handle. It's old-school, but you know what? Those old-school ways worked, and worked well for a reason. I'll bet you a lunch that the more complicated a knife becomes, the higher the failure rate for that model. Be interesting to know the stats on how many folding knives fail compared to one-piece knives at the same approximate quality level (don't compare a WalMart folder to a Reeve one piece or vice versa)...
    Last edited: Aug 30, 2019
  16. Tseg


    Aug 25, 2018
    If a knife was only meant to cut, folding knives would not exist. They only cut when open. But why do they exist? Oh, because they have the additional job of adding safe transport. Diamonds in knives? An expression of art? An expression of wealth? Implying a knife’s job is binary is projecting.
    marrenmiller likes this.
  17. robgmn


    Oct 30, 2015
    A knife exists to cut, not "provide safe transport" or fold. If it existed to provide safe transport or fold, there would be no need to sharpen the blade or even have a blade.
    Safe transport? Sheath. They've existed far longer than folders.

    But again, don't lose sight of what I said in my original post and try to paint me as anti-folding knife, anti-ball bearing, etc.
    They're all fine, but don't try to make them into something they're not.
  18. ColoradoHoldout


    Jul 18, 2019
    I love ball bearing systems. Some of my favorite knives, the ones that have the most satisfying 'feel' to their action, had ball bearings, like the Swish or Reate Baby machine.
  19. ColoradoHoldout


    Jul 18, 2019
    Because the benefit doesn't come from strength or durability. The benefit of bearings is to improve the smoothness and action of the knife. There is definitely a difference in how the action feels, and some people, like myself really prefer the 'feel' of bearings.

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