Thomas Mercer Survey Chronometer Maintenance

Discussion in 'Chronometers' started by jans, Feb 13, 2020.

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  1. jans

    jans jans

    Feb 26, 2009
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    I recently purchased a Thomas Mercer Survey Chronometer. It is running accurately for over a month, having stopped only one time. The question I have is: Do I have it cleaned and lubricated as a general precaution or just continue to run it until it malfunctions? I have no idea when it was last serviced. I am in New York City and haven't local expert; my clock guru is several hours drive and shipping it is not safe.
     
  2. gmorse

    gmorse Registered User
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    Jan 7, 2011
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    Hi jans,

    No, you certainly should not continue to run it. If you do this you risk doing damage which could be very costly to remedy. These instruments require knowledge and skill to dismantle and service, (and also to some extent to manage on a daily basis), and people competent to do this work are few and far between.

    Regards,

    Graham
     
  3. jans

    jans jans

    Feb 26, 2009
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    Thanks Graham- Any people in NYC that do these clocks? One shop said that it needed to be serviced by a watch technician, and that I should keep it running or oils would dry out and it would stop altogether.
     
  4. gmorse

    gmorse Registered User
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    Hi jans,

    It does need to be serviced by a competent technician who's familiar with chronometers, but I'm not sure which century that shop is living in. At least you've established which shop you shouldn't send it to! Yes, oils do dry out over time, but that's a very good reason for not running it, because aged oils will have attracted dust from the environment and tend to form an abrasive paste, which will cause wear in the pivots. There are other considerations if a chronometer is allowed to run right down and stop, the main one is knowing how to start it up again to avoid damaging the very delicate escapement. These are precision instruments and can't be treated like any ordinary watch or clock.

    Regards,

    Graham
     
  5. jans

    jans jans

    Feb 26, 2009
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    Graham- I have noticed on some photographs of ships chronometers a sticker indicating when last serviced and by an outfit that has done the service. I would imagine that those shops are closed by now. Would a fine watch repair shop be able to handle this? And can you suggest a link or other source where I might find more details about the care and operation of this type of clock. I'm in New York City and I have yet to find a local clock repair that can reliably service the various clocks that I have. Perhaps it's best to just leave this clock in the case and not run it. I'm not sure how many more dollars I should throw at it, particularly as it may need the service in an all to short time. And with the kind of reliability I've experienced after some services, I'm wondering if it may be better to not meddle unless there is a person who is fully qualified.
     
  6. bruce linde

    bruce linde Technical Admin
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    Nov 13, 2011
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    my rule of thumb is: if you don't know when it was last serviced, it needs it.

    as others have said: this is a precision instrument and needs to be treated accordingly. get it serviced right by the appropriate expert and then enjoy it. until then, let it rest.
     
  7. Ralph B

    Ralph B Registered User

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    Perhaps a mod could move this to the "Chronometer" forum ?

    I don't run mine, not until I find the time to strip and clean it.
    Even carrying one around can cause it to trip and damage itself, ( apparently, haven't done it myself but Cmdr Gould warns about it in his famous book, "The Marine Chronometer".

    Ralph.
     
  8. gmorse

    gmorse Registered User
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    #8 gmorse, Feb 14, 2020
    Last edited: Feb 14, 2020
    Hi jans,

    Having it serviced by someone who isn't fully competent could be disastrous. As you can see, I'm some way away from you, but there are some people in the US who could advise you, in particular DeweyC.

    There's a helpful little book by W.J Morris called 'The Mariner's Chronometer', (ISBN 9781480121850), which explains how they work and how to handle them, but please don't be tempted to try anything more adventurous!

    Regards,

    Graham
     

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