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More Problems With my Balls

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  • More Problems With my Balls

    A week or so ago another forum member sent me a pair of balls - for a Jacobs 18N chuck, and now I've got another ball-related problem:

    Looking at the 4" import vise on my mill last night I noticed something protruding from the recess behind the handle where the thrust bearing is - it was part of the bearing. I took it apart this morning and the picture below shows what I removed. From left to right are: One race, the other race - worn through into two pieces, the remains of the bearing cage, and finally, the balls. The vise is about 5 or 6 years old, and somewhere in those past years I took it apart and the bearing was intact then, but it could have been closer to 5 years ago. Aside from the failed bearing the vise i as good as can be expected for something that cost around $100 delivered. the half-ball that forces the moveable jaw down is fine and the castings are all reasonably good - I came across Doc's writeup on rebuilding a 4" import vise and I admit I didn't go to the depths of measuring that he did, but it sounded like mine was a lot better to start with.

    So, I need to buy a replacement bearing and it looks like what i need is a 51104 thrust bearing - 20mm x 35mm x 10mm, based on what I can guess the original might have looked like. Since I don't want to wait 2 weeks for a bearing from China I'll order one from the USA. I can get an NTN (Japan) bearing for about $17 shipped where it's about $14 for what is likely another Chinese made one. I'm going to hope the NTN is a better choice.

    Now, what do you guys think caused this? Is it likely to be only poor quality bearings, or am I cranking the thing down too much? like I said before, everything else looks fine on the vise.

    http://i908.photobucket.com/albums/a...ps6177879a.jpg

  • #2
    It was probably a junk bearing to begin with. Get a new one, grease it up good and keep on keepin' on.

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    • #3
      I imagine it was dry for too long. And/or got dirty. I would not use grease as that may attract and retain chips should they get inside the bearing/housing. Which will replicate the bearing you now have. There should be an oil feed hole in the vise casting for oiling. If not, get and install an oil fitting to allow oiling.
      Krutch


      Mentally confused and prone to wandering!

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      • #4
        Never underestimate china's ability to use really poor steel alloys in strange places. Iv got a drive gear on a motorized bike that keeps chipping and cracking every few months of driving it. thankfully they only cost $4 to replace or id be upset.
        Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

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        • #5
          I bet they're underinflated & probably a lost cause
          "Let me recommend the best medicine in the
          world: a long journey, at a mild season, through a pleasant
          country, in easy stages."
          ~ James Madison

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          • #6
            Originally posted by Black_Moons View Post
            Never underestimate china's ability to use really poor steel alloys in strange places. Iv got a drive gear on a motorized bike that keeps chipping and cracking every few months of driving it. thankfully they only cost $4 to replace or id be upset.
            i'm wondering (and hoping) this is the case. it has a spring loaded ball oil port and i would often put a few drops into it. it certainly wasn't dry when i dismantled it all. the parts of the bearings that weren't deformed had ground themselves up and combined with the oil i had used to lubricate it, thus making what looked like silver neversieze. i have an ntn thrust bearing en route, and hopefully that will make life good again. assuming the weather doesn't lose the bearing. and hopefully i can find the garage under the snow drifts. last time i looked before it got dark i had one car buried in a drift. guess i know what i'm doing tomorrow - snow removal.

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