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Lathe Bull Gear Needs A New Tooth???

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  • Lathe Bull Gear Needs A New Tooth???

    Hi all,

    I have an old SHeldon Lathe from the 50's that needs one new bull gear tooth. I pinned, brazed, and filed a new tooth on and it looks good vut it makes a pop type of noise when it hits the back gear. Under presure of cutting it makes no noise at all what so ever but when I release the half nut and wait for the dial to come back I get pop pop pop etc. I will never get the gear correct the other teeth have wear on them already. DO you think this is ok to run as is? If not what can I do??

    Thanks
    Joey V.

  • #2
    Why not blue up the teeth with some Prussian blue, run the lathe a few turns and look at the wear pattern. If you have high spots they should show up and you can work them down, re blue and continue the process until the pattern looks close to the pattern on the original teeth,

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    • #3
      You might be able to come up with a replacement gear via Ebay, or maybe an outfit like Plaza Machinery.
      The Yahoo Sheldon group is another resource: http://groups.yahoo.com/group/Sheldonlathe/

      Your repair may last a long time, but then again, it may not.


      Rex <<Sheldon R15 owner

      Comment


      • #4
        Originally posted by firbikrhd1 View Post
        Why not blue up the teeth with some Prussian blue, run the lathe a few turns and look at the wear pattern. If you have high spots they should show up and you can work them down, re blue and continue the process until the pattern looks close to the pattern on the original teeth,
        This sounds pretty easy. Remember to take your time and re file lightly. The area is so small that you can really take your time and still be done pretty quickly. If you do this, and are still not happy, you still can buy a new gear.

        This method is scraping - it's just on a strange shape. Half the difficulty of scraping is getting a good master and blueing in good alignment. All of that is built in here.

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        • #5
          I expect you'll get lots of thoughts on this and I'll throw mine in. I have in the past lost a few teeth I did a very similar fix and it's still running and that's about 5 years. My method was to drill and tap in some little number 10 bolts file them a bit and then build the whole thing up with brazing rod. The brass then gets filed into the tooth shape with lots of checking with bluing. When turning it over by hand I could feel a very slight increase in resistance when it got to the repair. It was very slight and as I said it's still working fine. I had no noise but if your repair has brass running against steel then I think the steel will loose and at the worst you will have to do the repair again.
          I have also had gears made by a shop that does nothing but gears and it cost about $200. for a bull gear on on 14 x 40 lathe

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          • #6
            Contact info?

            Hey Bill Can you give me the shops contact info? I had some joker wanting to charge me $1200 for a new bull LOL. I payed $1000 for the lathe and tools!
            Thx

            Originally posted by Bill McLeod View Post
            I expect you'll get lots of thoughts on this and I'll throw mine in. I have in the past lost a few teeth I did a very similar fix and it's still running and that's about 5 years. My method was to drill and tap in some little number 10 bolts file them a bit and then build the whole thing up with brazing rod. The brass then gets filed into the tooth shape with lots of checking with bluing. When turning it over by hand I could feel a very slight increase in resistance when it got to the repair. It was very slight and as I said it's still working fine. I had no noise but if your repair has brass running against steel then I think the steel will loose and at the worst you will have to do the repair again.
            I have also had gears made by a shop that does nothing but gears and it cost about $200. for a bull gear on on 14 x 40 lathe

            Comment


            • #7
              I would just make one from mid steel. This not hard to do (ring gear or plate gear) please post a photo

              Dave

              Comment


              • #8
                +1

                Although I'd check the mating gear pretty closely as it seems that in many cases it might have been caused by excessive force when removing a chuck.
                Last edited by oldtiffie; 11-30-2012, 04:32 PM.

                Comment


                • #9
                  Originally posted by Bill McLeod View Post
                  --if your repair has brass running against steel then I think the steel will loose
                  Unless there goes something harder than that steel, in which case the foreign matter will push in to the brass and act like a lapping compound or abrasive there and eventually wearing out the steel part.

                  Have seen numerous lathe screws that have had the steel screw worn down completely while the nut has been almost like new. And in every case the reason has been foreign matter between the parts.
                  Amount of experience is in direct proportion to the value of broken equipment.

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                  • #10
                    might as well tell everybody he does have good prices and is a good guy, very well set up for gears the only thing is like me he is in Canada but does ship anywhere. it's Golden Gear his name is Vinnie Lai 604-324-8882 address is 11526 Twigg Place Richmond BC V6V 2Y5 no email address on his card.

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                    • #11
                      I've never had to do this before but after reading your post the first thing that came to mind was to cast a portion of the good section of gear in plaster of paris or some other concoction like an epoxy that will not shrink when it dries and use this as a filing template. Not only will you get the gear tooth filed to the proper geometry but you will also get it centered relative to the other teeth. I'm going to go out on a limb and suggest that perhaps the problem is due to the new tooth not being properly centered.

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