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Switch for a Rockwell Mill

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  • Switch for a Rockwell Mill

    I just bought a Rockwell milling machine that appears to be in pretty good shape. The guy I bought it from said he didn't know why the reverse didn't work. I pulled off the switch cover and out popped a contactor and a small spring. The rest of the switching contacts have burn marks and pitting.

    I just went to the electrical supply house and the guy did a bit of research and came back with a quote of $475 for a switch. I don't think so, all it is is a bloody switch.

    Any recommendations on a switch I can buy (120v 1phase) economically? If I can't find an inexpensive one, I probably will wire 2 switches, one forward and one reverse and put a toggle between them so only one can be turned on at a time.

    Any suggestions or comments?

    Thanks, Dennis

  • #2
    Look for reversing drum switches. Here are Graingers selections;
    Jim H.


    • #3
      Thanks, I'll look for one.


      • #4
        OK, so now I feel retarded

        I'm have a bit of difficulty figuring out how to wire a new reversing switch.

        I bought a Dayton 2x441A drum type reversing switch.

        I cannot figure out how to add a pic, so I will do my best to explain.

        The tag on the motor (Rockwell) shows six leads, (T1, T5, and T3 wired together) and (T2, T4 and T8 wired together). "To reverse rotation, interchange T5 and T8."

        The Dayton switch has 6 terminals, numbered 1,3,5 on the left and 2,4,6 on the right, looking at the switch with the handle at the top.

        The diagram inside the switch indicates for

        Forward rotation,
        terminals 1&2 connected
        terminals 3&4 connected
        terminal 5 not connected

        Reverse rotation,
        terminals 1&3 connected
        terminals 2&4 connected
        terminals 5&6 connected

        However, when I check with an OHM meter,

        Forward rotation, I have continuity between:
        terminals 1&2
        terminals 3&4
        Terminals 5&6, (terminal 6 should be isolated)

        Reverse rotation, I have continuity between:
        terminals 2&4
        terminals 5&6
        terminals 1&3 have no continuity

        I've wired up a lot of machinery before, but I'm stumped on this. I used an ohm meter to check which terminal connects to which when the switch position is changed.

        I hope I explained it well enough.

        Thanks, Dennis


        • #5
          Here is a link to the army manual for the Rockwell machines, there are several different wiring diagrams for the various motors in it. Perhaps it will be of some help. It is well worth having at any rate.

          Jim H.


          • #6
            Thanks for the link. I was hoping to find a manual for the machine.

            The wiring for the motor is pretty straight forward, the part I am confused on is the wiring of the reversing switch.

            I'm going to look at it again today, maybe I was too tired to make sense of it last night.

            Thanks, Dennis


            • #7
              There are diagrams for reversing switches in the manual. Take a look, you will need to go to the section for the vertical mill.
              Jim H.