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W/T Table raising Gearbox Repair

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  • W/T Table raising Gearbox Repair

    I sold my Delta 17" drill press and moved this 20" Walker Turner machine into my shop. I had previously redone the spindle and spindle pulley bearings. On the spindle pulley, I machined the shaft to take normal bearings, rather than the odd sized ones that Walker Turner had used. After getting it into the shop and I got into going over it, I realized that the table raising gears were in really bad shape. I found a replacement worm gear on EBAY and ordered it up. This was a new area for me and once you figure out the codes, it is not hard to find what you need. This is a 1220-SR, 12 pitch, 20 teeth single thread, right hand. I went with bronze vs the steel that was there. I also decided to put in a needle thrust bearing on the worm shaft to replace the fiber one.

    The gear was bored ½" when I received it and the shaft was most of 5/8". I bored it out with a boring bar and then fitted it with an adjustable reamer to a tight hand fit. The next challenge was the key way. I had heared that I could do them on the lathe, but I thought the drill/mill would work better as a broaching set up. I found a 5/8" boring bar that took a ¼" square cutter and turned the bar down a little to get some running room in the bore and ground the cutter to just under 3/16" for the key way and it worked like a charm! After the key way was cut and the setscrew hole drilled and tapped, I finished off the gear to the correct width.

    For the needle thrust bearing, I milled off the housing and handle hub square and flat and also milled two flats on the worm shaft. I had tapped the pin holes in the handle hub for 5/16" setscrews rather that stick with the pin. This allows me some adjustment on the worm shaft/ handle/ thrust bearing. The bearing makes a big difference. I tried it without first so I could see if it helped.
    Peter

    Broaching the key way


    Close up of the set up


    The needle thrust bearing


    The old and the new
    Grantham, New Hampshire

  • #2
    Great job, I will put this into my memory bank . Problem is I have put a lot of things in my bank but I keep forgetting where I hid my memory bank.
    Last edited by lugnut; 12-12-2017, 08:22 PM.
    _____________________________________________

    I would rather have tools that I never use, than not have a tool I need.
    Oregon Coast

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    • #3
      Nice.

      When I did the Atlas/Clausing 1800 drill press, I had to make a new bevel gear from scratch. The original one was zamak, and was so torn up that it jammed. The price for a new one was nearly what I paid for the DP.
      1601

      Keep eye on ball.
      Hashim Khan

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      • #4
        I have used those needle thrust bearings in several places. They really make things work easier. They are very inexpensive and come in many sizes.
        Grantham, New Hampshire

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