Repivoting without tempering

Discussion in 'Watch Repair' started by DeweyC, Apr 18, 2019.

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  1. DeweyC

    DeweyC Registered User
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    Feb 5, 2007
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    There was a discussion on pivoting in the Clocks Repair forum which led me to post this there this am. I thought it may be of interest here. Sorry for the double post. I do not soften arbors for repivoting.

    This is a LeCoultre A/C clock and the wheel is the 4th wheel with a 30/100 mm pivot. Arbor is 1.1mm OD.

    This had to be done this AM so I thought I would show how to do it with a WW lathe, carbide graver and carbide twist drill. This is a standard twist drill (50/100mm) but I could have broken off a smaller ckt board drill and choked up on the drill itself to reduce overhang and wobble. Took about 5 minutes; but remember this is my bread and butter.

    This can also be done with a pinvise but remember to control your pressure. Much easier if you have a matched tailstock.

    Sorry about the "through the looking glass" photos; did not want to set up the SLR.

    First photos show how I set up to cut the female center. AS you can see, a microscope gives much better working distance and you are not guessing at what you "see".

    Second series show the setup for actual drilling and how to setup for hole depth (1.5mm here; short pivot that is 30/100). Note the swarf. You need to see what is happening so you can withdraw the drill; if the swarf clogs it will break the drill. Also, high speeds can actually heat the setup so that the drill seizes. Crawling speeds.

    Second to last photo you may see a line in the eyepiece. This is a reticle that allows me to measure .025 mm increments directly. Makes turning lengths a pleasure.

    Although I have not really thought about it, I do not see how this work can be done on Sherline lathe.


    447251-d883c9d88278943d0ad5bc44e896c867.jpg 447250-c231e98a50d8ef12635e2e5ef83b9be1.jpg 447253-d846e4a92dcaa4f387a72d04f2de293d.jpg 447252-ddf8dc8b8b06f0aa913b2f3b988eedfc.jpg 447254-debd4aa383c989e14779ffc476706ee1.jpg 447255-e3a4e414f7d9afc42f03d7758789d4f1.jpg
     
    Dave Coatsworth likes this.
  2. praezis

    praezis Registered User

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    Hi,

    your pictures are too tiny to see details.

    Frank
     
  3. DeweyC

    DeweyC Registered User
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    Oops. Now the files are linked. Thanks!

    Female Center.JPG Female Center Setup.JPG Drill Check.JPG Drilling setup.JPG Swarf nd Cutting Action.JPG Setting depth.JPG
     
  4. praezis

    praezis Registered User

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    Hi D.,

    better now :)
    I do this work the same way (with slight variants). 20/100mm and above is easy to me, smaller makes great problems. I suspect the runout gets dominant then. I realized even differing results with 2 different Schaublin collets of the same number.

    Frank
     
  5. DeweyC

    DeweyC Registered User
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    Frank,

    I also have found you have to know your collets. Even the work sometimes needs to be rotated within the collet to have it run true.

    Did you look at the reticle scale? Really makes life more pleasurable when turning lengths.

    Regards,

    Dewey
     
  6. praezis

    praezis Registered User

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    Yes, a real advantage.
    I do not use a microscope, just my Zeiss stereo loupe.
    For depth control and to avoid sudden progress I added a simple device to the tailstock spindle:
    tailstock stop.jpg
    Frank
     
  7. DeweyC

    DeweyC Registered User
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    And you know about using the feeler gauges to set your tailstock depth stock. More for the benefit of others who are following our discussion.

    Regards,

    Dewey
     

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