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O.T. paging J.Tiers

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  • O.T. paging J.Tiers

    Mr. Tiers
    I was reading on another board about problems you had with one of your lathes involving a 5207 bearing.
    Sorry to bring up old material for you; I can't access it. But here's my question(s):

    Did you essentially add provision for pre-load to what appears to be a cheap bearing, and are there still just two bearings on the spindle? (the 5207 plus the single row at the other end)

    Has this proven acceptable for your purposes, i.e. what sort of run-out?

  • #2
    Forgot to ask, is the high end ~1400RPM and what sort of temp. rise there?

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    • #3
      Scratch the request. Sorry to bother!

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      • #4
        Well you get your answer anyhow.....

        yes it was very acceptable, No I did not "substitute", what I did was to ADD a bearing which is coupled to the spindle ONLY by the bellevilles. I applied about 90 to 100 lb axial preload.

        The "cheap" bearing was NOT particularly cheap, and was sourced from Logan, for a Logan model 200. It had all the slop to be expected from a C3 bearing, and most certainly didn't work. It HAD worked, because of another issue that had applied a preload that wasn't supposed to be there. After I "fixed" that issue, the machine was not usable, it chattered so badly.

        Turns out from what I heard elsewhere, that Scott Logan at that time apparently didn't know the original spec for the bearing, so he did not specify a zero-to-negative clearance. I got a bad one, but them's the breaks. I drew the line at buying another one from him, though, that was just too raw.

        As for top speed and heating, I have no idea. Preload will not affect it in the least. The bearing has something like an 8000 lb rating...
        1601

        Keep eye on ball.
        Hashim Khan

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        • #5
          Thank you for taking the time to reply. "Cheap", in comparison to many other bearing set-ups, often paired AC in the front. I hadn't mentioned names as I have no interest in impugning products or individuals.

          From reading your original situation there was obviously time and aggravation involved and I'm pleased you reached a solution, just curious what it was.

          So based on that do you feel this is an acceptable "design" or was it constrained by existing conditions and the conclusion is "good enough" ?

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          • #6
            It's fine. I see nothing particularly wrong with it.

            I'd bet that one of the replacements that Scott sells these days could be better, because the preload is probably going to be more rigid when it is all held inside one housing, with no compliant mechanisms other than the stretch of the outer race and compression of the inner race.

            Against that is the fact that the bearing is held by a split ring, with a certain amount of movement to it. My arrangement preloads the entire setup, including the split ring arrangement, so any play in that is taken up as well.

            Later machines were made with a preloaded setup using belleville springs and NOT using the dual row bearing. So the plan is perfectly workable.

            As for impugning individuals, I don't think it does. It's a perfectly honest mistake, and if it had not taken so long to discover the problem, I might have gotten a replacement from Scott for the obviously defective part.

            I admit I was not too pleased at the time. But a lot of that was due to others on the Logan group calling me a liar, and various other names. Someone even went so far as to TWICE spoof my email address and unsubscribe me from the group. Felt like a tractor forum for a while.

            Several other folks with the same problem asked for the details of the fix, which I provided. Obviously I was not the only one.
            1601

            Keep eye on ball.
            Hashim Khan

            Comment


            • #7
              Originally posted by J Tiers View Post
              I admit I was not too pleased at the time. But a lot of that was due to others on the Logan group calling me a liar, and various other names. Someone even went so far as to TWICE spoof my email address and unsubscribe me from the group. Felt like a tractor forum for a while.
              Well, we (we as a people) could have a protracted discourse over the lack of civility on the webz and apparent decline in civic life.
              For the moment, I again thank you for the rejoinder.

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