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RE: [atlas_craftsman] Re: This should be easy - bearings another option

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  • Carvel Webb
    For what it s worth - maybe another option . It s called Use a lathe to fix a lathe and it happened 35 years ago J . . . .. . My first Atlas in 1978 was a
    Message 1 of 2 , Aug 31, 2013
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      For what it’s worth – maybe another option .

       

      It’s called “Use a lathe to fix a lathe “ and it happened 35 years ago J . . . .. .

       

      My first Atlas in 1978 was a complete but sad 10D with worn out headstock ( white metal) bearings .

       

      A turner/fitter friend of mine turned out phosphor bronze bearings with collars and oil grooves to replace the white metal .

       

      The bearings were turned slightly undersize bore and slit into two half shells .

       

      The headstock with shells with shims equal to the slit thickness was then placed on another Atlas lathe ( a newer 10F) between the headstock and the carriage , which had a boring bar mounted between centres, and was lightly clamped so it could slide  .

       

      The 10D headstock was then “line bored” by pushing it with the carriage so that both new bearings were bored / skimmed to the diameter of the spindle ,

       

      The end result was accurate enough for my purposes and this lathe served me well until replaced by a TH42 QC some 10 years later ,

       

      Probably no reason why a white metal headstock could not be ‘line bored’ on another Atlas the same way if it is a sliding fit as mine was  , but I have never tried it ,

       

      Regards,

       

      Carvel

       

      From: atlas_craftsman@yahoogroups.com [mailto:atlas_craftsman@yahoogroups.com] On Behalf Of wa5cab@...
      Sent: 01 September 2013 05:48 AM
      To: atlas_craftsman@yahoogroups.com
      Subject: Re: [atlas_craftsman] Re: This should be easy: Fair value guestimate on 101....

       



      The practical problem with pouring new babbit bearings using the existing spindle as part of the mold is that you have to be able to place and hold the spindle in the correct location.  You need to be able to locate and hold the spindle within probably +/- .005" front to back, +/- .001" up and down, and at a guess .0005" in 12" in both pitch and yaw.  In other words, you need to be able to pour bearings as accurately as the factory originally line bored them.

      Robert D.

      In a message dated 8/31/2013 6:27:26 PM Central Daylight Time, jerdal@... writes:

      Hmmmm....
       
      If poured in place and left, there is a tight clearance... usually there is some work to scrape them to fit, if you use a "model shaft"  . If you pour around the actual shaft, you still have a tight clearance, but it may wear out to be OK, will be hot for a while.  Probably it will be too close for good oiling, though, depending on the shrinkage.
       
      Do you count scraping oil grooves as "disturbing" the babbit?
       
      JT



      Robert & Susan Downs - Houston
      wa5cab dot com (Web Store)
      MVPA 9480


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    • Jon Elson
      ... This is essentially how the lathes were made at the Atlas factory. They did this on a special-purpose machine, but it is almost exactly this process. Jon
      Message 2 of 2 , Sep 1, 2013
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        Carvel Webb wrote:
        >
        >
        > It’s called “Use a lathe to fix a lathe “ and it happened 35 years ago
        > J . . . .. .
        >
        > My first Atlas in 1978 was a complete but sad 10D with worn out
        > headstock ( white metal) bearings .The headstock with shells with
        > shims equal to the slit thickness was then placed on another Atlas
        > lathe ( a newer 10F) between the headstock and the carriage , which
        > had a boring bar mounted between centres, and was lightly clamped so
        > it could slide .
        >
        > The 10D headstock was then “line bored” by pushing it with the
        > carriage so that both new bearings were bored / skimmed to the
        > diameter of the spindle ,
        >
        This is essentially how the lathes were made at the Atlas factory. They
        did this on
        a special-purpose machine, but it is almost exactly this process.

        Jon
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