RR Pocket Watch Regulation

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    I’ve just overhauled a Waltham 18, 17 jewel pocket watch. It is keeping really good time, compared to some of the 5 to 11 jewel movements I’ve done. What would be a normal +/- seconds per day for a Rail Road type pocket watch?

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    From an article attributed to Ed Hahn:
    The constant in all of this was that railroad watches needed to maintain a standard of timekeeping of less than 30 seconds of error over a week “.


    And keep in mind that it was ( is ) not acceptable for an accurate watch to lose or gain a large amount every day,..IE 10+ one day, and 30- the next, even if it averages out to meet the weekly rate.
    Much better to have it gain/lose 4-5 seconds per day, steady. Better example of constant Isochronism.

    So how’s it doing ???

    Best regards,


    david pierce
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    The standard for railroad watches and certified chronometers in general was + or – two seconds per day or one minute per month in six positions within a given temperature range. Crystal controlled electronic watches can hold the time within 5 seconds per month in any position within a greater temperature range, which is why they overshadowed mechanical watches.
    David Pierce

    • Topics Started: 34
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    I guess I have a long way to go. It gains about 30 seconds per day.

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wingmanRR Pocket Watch Regulation