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Really, really small gear....really

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  • Really, really small gear....really

    I have a 60s or 70s vintage Pam electric clock that stopped working. I took it apart and found a gear that I believe is some type of fiber that is missing about half its teeth(all other gears in the movement are brass).
    I have looked online and facebook but no luck.
    I am a hammer and chisel machinist, is there anyone here that might be able to make a new gear?

  • #2
    Did you try Stock Drive Products?

    http://www.sdp-si.com/products/Gears/Index.php
    Keith
    __________________________
    Just one project too many--that's what finally got him...

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    • #3
      Give us some dimensions and the number of teeth for the gear. There should be enough of it around one edge or the other to allow measurements of this sort. And while you're at it the length of it and the size of the shaft it has to fit onto.

      I know that over the years I've saved all my small gears and I'm sure that there are others in the same boat. One of us might have what you need.
      Chilliwack BC, Canada

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      • #4
        If you can't find a gear, read this: https://www.amazon.com/Machinists-Pu...SIN=1565239172

        Clickspring has a series of You Tube videos on reproducing the Anklyathera(?) machine and is cutting gears with a file.

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        • #5
          Originally posted by BigMike782 View Post
          ... is there anyone here that might be able to make a new gear?
          Depends on what you want to apply to your resources of searching. Once you have exhausted the readily obvious sources and find no love, I'm sure that I can help. But definitely try other avenues first. Even looking on eBay for a replacement clock to steal parts from.

          One the larger ones done lately - ( in process, pre-grinding )



          Finished up -



          Some from the past -



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          • #6
            If it is the type gear I am thinking of from other electric clocks, those gears are huge by comparison.

            I'm thinking his gear may be 2 or 3 mm diameter overall.
            1601

            Keep eye on ball.
            Hashim Khan

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            • #7
              Originally posted by J Tiers View Post
              If it is the type gear I am thinking of from other electric clocks, those gears are huge by comparison.
              I'm thinking his gear may be 2 or 3 mm diameter overall.
              Definitely agreed. Unfortunately, those are just what I had readily at hand. I've made hundreds of gears that small over the years. I just don't have their pictures handy at the moment.

              Wait! ... dangit... nope... these are still a little large...

              Last edited by Zahnrad Kopf; 03-23-2019, 01:22 PM.

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              • #8
                ZAHNRAD, I have a question about the gears in the pic with the quarter
                The side by side ones, are they done on the gear shaper ?
                I am asking because without a groove at the bottom, I can't see how the chip breaks.
                Or are they done with a small endmill ?

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                • #9
                  You could try an RC/ model/ hobby shop...

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                  • #10
                    Took some pics today and will try and post this evening from the laptop.
                    Largest dimension is just over 5/8”....small enough I can barely hold it free hand.

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                    • #11
                      Originally posted by 754 View Post
                      ZAHNRAD, I have a question about the gears in the pic with the quarter
                      The side by side ones, are they done on the gear shaper ?
                      I am asking because without a groove at the bottom, I can't see how the chip breaks.
                      Or are they done with a small endmill ?
                      End mill? From a self admitted GearSnob™️? Heavens no...

                      No, those were a two piece design.** If you look at some the others in the picture, you can see the other side of them that illustrates the DoubleD feature used to insure against rotation, along with the press fit.

                      **- Many of the larger, more common, traditional gear shapers don’t deal well with the smaller pitches such as these, due to the correspondingly smaller relief groove, and they also wanted to maintain a certain maximum Face Width. So, other methods are some times employed. As well, those were prototypes for a widget that was headed to market and they wanted to torture test some prototypes but also maintain some economic frugality while doing so...
                      Last edited by Zahnrad Kopf; 03-23-2019, 05:05 PM. Reason: Added a missing word

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                      • #12
                        Ahhhh, I had thought maybe pinned .. thanks.
                        In traditional gear shaping a double gear needs a groove or relief to let chip break, is what I was thimking.
                        Last edited by 754; 03-23-2019, 04:51 PM.

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                        • #13
                          Originally posted by 754 View Post
                          Ahhhh, I had thought maybe pinned .. thanks.
                          In traditional gear shaping a double gear needs a groove or relief to let chip break, is what I was thimking.
                          No worries. It was clear.
                          Anecdotally, I’ve done literally thousands of little guys like these, and am a big fan of the DoubleD ( or even Single D shape ) for anti rotation preventative measure. It’s a quick and easy way to do so while still maintaining the quality of the press fit and also avoiding other extra measures. ( like pins, screws, keys, or welds )

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                          • #14
                            Originally posted by Zahnrad Kopf View Post
                            Anecdotally, I’ve done literally thousands of little guys like these, and am a big fan of the DoubleD ( or even Single D shape )
                            Its a good joint. My car has the double D for the steering column. Its pinned also. JR
                            My old yahoo group. Bridgeport Mill Group

                            https://groups.yahoo.com/neo/groups/...port_mill/info

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                            • #15



                              Last edited by BigMike782; 03-23-2019, 08:47 PM.

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