Mechanical WW Question about Eterna-Matic hairspring

Discussion in 'Watch Repair' started by Paul Raposo, Feb 4, 2019.

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  1. Paul Raposo

    Paul Raposo Registered User

    Nov 4, 2005
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    Cambridge, ON Canada
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    I picked up a nice co-branded Birks Eterna-Matic 1000. The watch was gaining 6 minutes a day.

    I put it on the timing machine and the beat error was between 5.6 and 6 in various positions. The amplitude was good in all potions.

    I put the watch in beat (between 0.8 and 1.0 in positions) but the movement was still very fast.

    I tried to regulate the rate using the gross regulation but the best I could do was +3 minutes per day.

    Looking at the hairspring with a stronger loupe I saw that there are two index pins and the boot. The spring is between the second pin and the boot and I'm thinking the spring should be between the two pins.

    I just want to double check this before I remove the balance and place the spring between the pins.
     
  2. Skutt50

    Skutt50 Registered User

    Mar 14, 2008
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    #2 Skutt50, Feb 4, 2019
    Last edited: Feb 4, 2019
    I just found this page showing how the hairspring should be mounted:
    Maintaining and Repairing Mechanical Watches

    Make sure the hairspring is centered and not resting on one side or the other. If it e.g. touch the boot the watch will run fast.....
     
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  3. karlmansson

    karlmansson Registered User

    Apr 20, 2013
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    Paul, could you post a Picture of the regulator in question? Two regulator pins and a boot?
     
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  4. Paul Raposo

    Paul Raposo Registered User

    Nov 4, 2005
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    #4 Paul Raposo, Feb 5, 2019
    Last edited: Feb 5, 2019
    Thanks for that link Skutt50, very much appreciated.

    I actually tried taking a picture but every one came out badly.

    Basically, instead of a boot and one pin, there are two regulator index pins and a boot. This movement is a 1479K.

    I decided to work on this last night and all went well getting the spring between the index pins.

    Over the last 15 hours the movement has only gained 37 seconds with the micro regulator centered.

    The beat error is also better at between 0.1ms and 0.3ms depending on the position.
     

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