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SB compound question

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  • SB compound question

    I'm working on retrofitting a South Bend milling attachment to a lathe of European design. It seems that South Bend cross-slides have two set screws (usually they stick out with square heads) each 45 degrees off axis from the crossfeed screw axis. Those screws push on beveled pins (aka "shoes" in SB lingo) which bear on a male circular dovetail on the bottom of the compound rest. Or milling attachment, or whatever else is mounted directly on the apron.

    Really what I need is someone with a 14-1/2" South Bend lathe to measure the thread (9/16-12?) and length of a screw and the OD and length of the pin it bears on ('shoe'). I already know the info for a 9" and a 10K but it's sort of moot because I'm working on a milling attachment from a 14-1/2" lathe.

    Thanks, metalmagpie
    Last edited by metalmagpie; 08-06-2012, 11:02 PM.

  • #2
    To tell the truth, I really never noticed and I dont think it matters, these pins or (shoes)
    should freely slide. People tend to over tighten and mushroom them, just ask anyone
    who has a SB from a school, thats an all day project getting them out. I finnally got
    mine to the point of the dovetail, and had to bang them in and out, then grind a campher
    now they will just come out with a pen magnet.


    • #3
      You might try the SB forum on the PM site they have many very knowlegable people there and would have an answer for you i'm sure. I have a 9" SB and a milling attachment, tommorow I will go look and see what I can then post what I find.

      Mr fixit for the family


      • #4
        The screw bears on a grub with a 45° angle on the end that bears on the circular post 45° relief. The threads do not go all the way through. The grub is 5/16 OD and the screw is 3/8" so it will not pass all the way through.

        However, on my SB9 South Bend also conveniently provided a pair of threaded holes that are covered by the top slide when it is installed. Very handy for attaching things other than the top slide. On mine they are 5/16-18.
        Free software for calculating bolt circles and similar: Click Here


        • #5
          Evanhas given you the correct info I checked mine today and it is the same as he states. The grug is 1" long if that helps any.



          • #6
            That's nice to know but I need the measured data from a 14-1/2" lathe, not a 9" or 10K, thanks! Just to clarify, I need dimensions for parts no. 42 and 43 from this drawing: sized for a 14-1/2" lathe.

            Last edited by metalmagpie; 08-07-2012, 06:32 PM. Reason: clarified