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Sealed Bearings

Discussion in 'General Knife Discussion' started by Shorttime, Jul 15, 2019.

  1. Shorttime

    Shorttime

    Oct 16, 2011
    Another thread got me wondering: are there any mfg'rs (custom or production), who use sealed bearings in the pivots of their knives?

    These guys:

    [​IMG]

    But, ya know... smaller.....
     
  2. danbot

    danbot Gold Member Gold Member

    Oct 31, 2009
    The Quartermaster QSE-10tt Biff Tannen is discontinued, but it used sealed bearings in the pivot.

    Crappy company, but a good idea.
     
    JJHollowman, jux t and Shorttime like this.
  3. marrenmiller

    marrenmiller Basic Member Basic Member

    Apr 6, 2017
    I'm interested to know this as well.

    The closest thing I've personally seen to sealed bearings on a knife is on my SBD Evo Typhoon, which uses regular caged bearings but presents virtually no part of the bearings to the outside, due to how deeply they're nested in recesses in the blade and handle. I can't imagine dirt getting in to those bearings in any significant quantity.
     
    kniferbro likes this.
  4. Barman1

    Barman1 Gold Member Gold Member

    Jun 21, 2013
    I've had a couple with o-rings seated around the pivot to seal from debris but I haven't seen any "sealed" individual bearings (although I'm sure it exists).
    The depth would be a drawback I suppose unless a single bearing could be used. But that would present tolerance issues unless the bearing were spec'ed for the application.
    I'm sure it could be done if enough money were thrown at it but in the end those costs trickle down to us suckers.
     
  5. golden_dragon

    golden_dragon Gold Member Gold Member

    636
    Dec 14, 2016
    In case you are looking for this:
    [​IMG]
     
  6. Comeuppance

    Comeuppance Fixed Blade EDC Emisssary Gold Member

    Jan 12, 2013
    That looks like a MRBS with milled tracks in the blade and a washer, which wouldn’t be quite the same thing. I have sealed bearings in my longboard, and they’re pretty chunky.

    I think the added cost of manufacturing bespoke slim sealed bearings might outweigh any practical benefits of such a system; I think what is pictured above is probably the best compromise, given that it accomplishes nearly the same thing without introducing the headache of trying to clean a sealed system (which will be a necessity eventually)
     
  7. Shorttime

    Shorttime

    Oct 16, 2011
    Well, I thought the space taken up by sealed bearings might be a problem.

    As for Quartermaster? Shame that I think it's an ugly knife with a near-useless blade from a company that's shady as anything .

    Now that I've seen it, I agree with the idea of shielded, rather than fully enclosed, bearings.

    I also started wondering if there will ever be an attempt to use rare-earth magnets to make a truly frictionless pivot?

    Knife-making fame, here I come! :D
     
    danbot likes this.
  8. kniferbro

    kniferbro Basic Member Basic Member

    Jan 22, 2011
    I've had an idea for a "sealed" bearing system that I've bounced around in my head for a little bit. Basically the blade tang and handle scales would have a thin circular channel cut right outside the diameter of the bearing cages and about 1 mm deep. This would allow a thin metal ring/band ~3-5mm tall to drop in and "fence" the bearings (2 rings, one for each side). Once the scales are fastened, the metal ring would essentially be sandwiched in the knife around the pivot, sitting ~1mm deep in both the blade and the handle, on both sides, creating a sort of fence to stop debris from getting to the bearings. This wouldn't be water tight (or maybe it could be) but depending on tolerances, I think it could prevent a lot of dirt, sand, lint, etc. from actually reaching the ball bearings. If you really tried I'm sure you could bypass the seal, but in general use I think it would hold up.

    Haven't really put too much thought into it so if you see a glaring flaw let me know...


    Don’t laugh, I just whipped this up in MS Paint lol! The red ring being the cut channel and the (crudely attempted) metal ring/band.

    [​IMG]
     
    Last edited: Jul 15, 2019
    Shorttime and WValtakis like this.
  9. Wowbagger

    Wowbagger Basic Member Basic Member

    Sep 20, 2015
    Problem is those cartridge bearings have play
    and
    seal drag
    so
    may as well use bronze washers (less drag and an adjustable pivot), a little VERY LIGHT oil and adjust it for minimal play.
    I just wish ALL of my knives pivoted like my 940-1, which has washers.
    I think more important than bearings is how accurately the knife is made.
     
  10. marthinus

    marthinus

    Dec 10, 2006
    Andre Thorburn has experimented with it as a busing system around the pivot and normal IKBS. Works well but tolerances need to tight.

    There is a video showing one of his knives taken down with it.
     
  11. Natlek

    Natlek

    Jun 9, 2015
    + problem is that water can get in but can not go out .They are sealed but they are far a way from waterproof ....
     
  12. Wowbagger

    Wowbagger Basic Member Basic Member

    Sep 20, 2015
    That's true.
    The bearings work well for electric motors etc. where the main problem is dust and it keeps the grease in the bearing. I think mostly they are easy for the factory to install, no adjusting, and fairly easy for the maintenance staff to replace not many parts and the units are fairly genearic and available.
    The heat from the motor would keep any moisture from atmospheric changes pretty much vaporized at least out here in the Wild Wild West.

    I know what you mean though; I have occasion to overhaul human powered recreational equipment and the "sealed" bearings do get water trapped in them fairly often.
     
  13. insta9ves

    insta9ves

    Apr 3, 2007
    Real Steel Harrier.
     
  14. Allan DeGroot

    Allan DeGroot

    215
    Jun 15, 2019
    I've never had a lot of faith in ball bearings, and wondered if anyone has used tapered roller bearings?

    One problem to overcome with tapered rollers would be getting the "preload" correct
    the other issue would be the lack of properly sized (small enough) tapered roller bearings,
    lastly their greater axial thickness...

    But should these issues be overcome, they'd be far stronger....

    OR alternately using a sealed double-roller for the pivot and roller thrust washers on either side,
    but I suspect either method would fit deeply into the category of "turd polishing", a grossly excessive solution for a fairly simple need. (Bronze and Teflon washers work)

    Mind you for the point of FULL DISCLOSURE I'm sitting here at my desk playing with my first Ball Bearing flipper knives, which one is actually first is debatable, but both arrived with today's mail...

    Both Chinese (Taiwan) branded "Doom blades" (so I have less than $30 (a touch more than a Chinese Kershaw) invested between them). My only real complaint is that the factory edge has a "micro-bevel" that was done wit too fine a hone (or diamond) so it's hard to make the edge "catch"...
     
    Last edited: Jul 19, 2019

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