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Looking for Bull Gear for an old lathe

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  • Looking for Bull Gear for an old lathe

    I have an old 1930 9" Model O southbend lathe in need of a replacement bull gear. The one that came with it has teeth missing in two areas. I currently am finding it difficult to find this gear. The gear is 5 1/8" in overall diamater and has a 1 5/16" bore with 70 teeth. It has 9-15 printed on the casting. If anyone has access to one please let me know.
    If you need pictures please let me know and I will provide what ever you need.

  • #2
    You might check with South Bend and see if it's still available. It'll probably hurt your pocketbook.

    For used, I'd check with Joe at Plaza Machinery. It'll still hurt, but not as bad.

    Or you might be able to repair or replace with a stock gear from someone like Boston Gear, but you'll need to know the P.A. (pitch angle) of the gear.
    Gears of different PA cannot run together, but I'm sure someone here will be able to tell you what it is on your machine.
    More precise measurements wouldn't hurt either, but you'll probably be able to get there with what you've got.
    Last edited by Scottike; 09-20-2011, 01:00 PM.
    I cut it twice, and it's still too short!


    • #3
      You'll find one eventually, if you watch eBay, and participate in some South Bend specific lathe forums , such as on Yahoo and Practical Machinist and Machinist Web.
      You may have to buy an entire headstock or at least a complete spindle. Some folk also repair and replace bull gear teeth.
      Last edited by Bill736; 09-20-2011, 01:24 PM.


      • #4
        Watch, also, for Hercus 9 parts - which should be interchangeable


        • #5
          Gears are sometimes repaired by this procedure:

          Grind or mill the broken teeth so you have a straight portion across the width of the gear.

          Drill & tap for appropiate-sized socket head setscrews, side by side, across the width.

          Build up a new tooth with braze around the SHSSs.

          Use a die grinder or Dremel to shape the tooth until it looks the same as the unbroken ones. Make a sheetmetal gauge to assist.

          This might be impractical if you have a bunch of broken teeth, but one or 2 can be fixed this way.

          A similar procedure can be used: mill out the broken tooth, down into the root, leaving a slot. Braze in a new "tooth", which can be already formed to the proper shape or you can do it after.




          • #6

            I have emailed Joe at Plaza machinery, he has not replied yet and I am looking at Ebay and have a request in at grizzly to see if they have one.
            Thanks again everyone



            • #7
              I]A similar procedure can be used: mill out the broken tooth, down into the root, leaving a slot. Braze in a new "tooth", which can be already formed to the proper shape or you can do it after.[/I]see:


              I've used this slot method quite successfully on a change gear, except that I didn't braze it in, I used Locset. The tooth depth was about 3/16", so I slotted down about 3/8". The new tooth was a piece of mild steel strip, milled to a snug fit in the slot, with the tooth profile filed on. It runs fine, you can't hear any noise from it. and after a few uses, I can't now even tell which tooth it was that I repaired. If the bull wheel is steel, then I'd be happy to use this method even if there are several teeth off at the same place, just slot for each tooth. If its cast iron, I'd be more wary because of the danger that the iron between the slots might snap off. Might give it a go anyway, its cheap and quick, and if it doesn't work you will be no worse off than you are now.



              • #8
                I agree with CAN repair gear teeth. I did on my ol' Ohio...ended up final shaping them with a thin file. The gears worked fine. These old machines don't run that fast and a repaired gear with likely outlast you...
                I have tools I don't even know I own...