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Thread: Bradford Lathe Bearing Fix

  1. #1
    Join Date
    Oct 2008
    Posts
    138

    Default Bradford Lathe Bearing Fix

    Here's the bearing that's behind the drive pulley on my Bradford Model 16. I noticed some side play in the shaft, found the brass piece worn by the inner race of the bearing and need to know how to fix it. Pressure applied to the inner race cures the side play.

    Is this brass ring a standard part?
    How can I tell if the bearing needs to be replaced? There aren't any pits or abrasions on the rollers or races.
    Is this bearing supposed to be packed with grease?
    Is the seal a standard part?






  2. #2
    Join Date
    Jan 2004
    Location
    Independent principality of Sinquefieldia (formerly Missouri)
    Posts
    16,985

    Default

    Is there nothing that adjusts the "preload" on the tapered roller bearing?

    I'd expect at least a spring of some sort. it would be on the shaft, as the inner races typically need to be pushed "inwards" to contact the outer race.

    It looks as if whatever adjusts the preload has given up and allowed the shaft to float end-wise until the bearing tore up the brass.

    The worn off pieces went somewhere, maybe into the bearings? That would have made it noisy and bumpy, but brass chips might not have damaged the races too much. Not like hardened steel chips.

    The bearings should typically be about 1/3 full of grease (plus roller carrier contents) for a greased lower speed bearing.

  3. #3
    Join Date
    Oct 2008
    Posts
    138

    Default

    JT-
    And that's why i'm asking the question here where those who know these machines are. I haven't done any measurements to see if there's any thing missing between the inner race and that brass ring. I also haven't looked in the manual for a diagram yet.

    The only experience I have with tapered roller bearings is from an old tractor that had bearings consisting of separarate races and rollers. Their tension was set with shims. It's been a while, but I don't recall the race rotating against the shim.

    I'll look at the manual to see what I can find.

  4. #4
    Join Date
    Jun 2006
    Location
    Austin, Texas
    Posts
    15,651

    Default

    It looks like you're missing the bearing cup -- the hardened outer race that the cone (the tapered rollers) run in.

    Is this bearing supposed to be packed with grease?
    Yes, unless it's in an oil bath, like in a spindle.
    Last edited by lazlo; 10-11-2009 at 02:48 PM.
    "Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did."

  5. #5
    Join Date
    Oct 2008
    Posts
    138

    Default

    I found the manual, and it looks like the back side of belt pulley hub provides pressure to the inner race. The outer race (cup) stays in the casting, and protrudes a little to align the oil seal housing.

    Seems like the pulley was not tightened enough, letting the inner race contact the brass oil seal retainer ring. Now all I need to do is find a "Perfect Oil Seal #33528" indicated in the drawing.

    Any ideas for a source?


  6. #6
    Join Date
    Nov 2007
    Location
    Woodinville, WA
    Posts
    4,989

    Default

    That's not a universal seal number - if it was you'd find it here : http://www2.chicago-rawhide.com/popu...kup_457010.htm

    Measure it.. (or the cavity/shaft/thickness) - dead easy to cross reference (it's metric)

    What you have pointed to as the "outer race" is actually the "cup". The bearing is the "inner" and the rollers are held by a cage.

    The brass looks "custom".. you may have to make it if the part is not available.
    Last edited by lakeside53; 10-11-2009 at 11:25 PM.

  7. #7
    gnm109 Guest

    Default

    Do you know the age of your lathe? My friend has a Bradford Mill that is a copy of a Belt drive Bridgeport. Your lathe is the only other Bradford I've seen.

    He doesn't know the age of his Mill.

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