Service: Omega calibre 351

IMG_8795The last watch in the batch of three that Anders sent in, and no less beautiful than the other two!

The dial has some patina, but this watch has seen quite a few decades of service, and it looks a lot better than a pristine restored dial on a watch like this. That’s of course my personal opinion…IMG_8797

The calibre 351 movement is in need of a bit of TLC.


A closer look at the dial. Again, a nice patina rather than damage.IMG_8800

The bottom plate – looks like the dial washer is missing.IMG_8801

Got to love those bumper movements!IMG_8808

The gear train.IMG_8810

It’s been a while since the last service. The grease has solidified, and this is a very old mainspring.IMG_8811

The parts of the keyless works.IMG_8812

Bottom plate cleared.IMG_8813

All the parts go into the cleaning machine. You can see how little tension the old mainspring has.IMG_8817

The (now) usual epilame treatment.IMG_8818

My last new mainspring that I have in stock, but don’t fear, I just ordered a new batch of 12 from Chris in Australia.IMG_8819

I start reassembly with the balance jewels.IMG_8821

The base movement is back together and ticking.IMG_8823

A very healthy amplitude. As the bear error is collet adjusted, 1.1ms is good enough, as it’s hard to get that any better.IMG_8824

The bottom plate is back together, and I’ve put a new dial washer on.IMG_8825

Movement cased without the winder weight.IMG_8828And back together.


11 thoughts on “Service: Omega calibre 351

  1. G’day Christian,

    I was lucky enough to inherit a 351 bumper, made @1953, from my father in law.
    It wasn’t working and was serviced here in Brisbane, Australia and thereafter kept quite good time and had about a 30 hour reserve in the original mainspring. Alas, one night I managed to break the mainspring and it went back in for service. After nearly 6 months of trying my watchmaker called me and said he could no longer get omega mainsprings. He replaced the spring (free of charge because it was still under warranty from the original service) with a non-genuine which keeps good time but has little non-winding reserve. I now have to use it like a manual.
    Can you advise how good, in terms of time-keeping and reserve, the mainspring you used in the article above? Also, can you advise me the contact details for “Chris in Australia” so that I can get a replacement mainspring?
    BTW, the dial I have on my Omega is time only (no extra dials) with the even hours shown as numbers and odd as lines, rather than 3,6,9 & 12 hours only shown as numbers or all hours as marks. First time I have seen this. Any opinion regarding this being unusual?
    I would hate to this this watch relegated to living in a drawer or cupboard.

    • Hi John,

      The mainspring fitted must be incredibly short if that has an impact on the autowinder not working – sounds a bit odd. You can get your mainspring off eBay: It’s a good replacement, and works as it should. I wonder if there are other issues if your autowinder doesn’t work with the mainspring that was fitted, though.

    • I use a cleaning machine that is pretty much the same as the Elma Super Elite. I put the balance back onto the plate after having removed the jewels in order to protect the balance staff and hairspring from any damage. The cleaning fluid can freely pass between the staff and the plate / cock, so you get a good clean of all the parts, without risking damage.

  2. Love the bumper movement, it looks very similar to the Tissot 28/5 movement apart from the springs, a much more elegant design on the Omega.
    My Tissot needs a service, but it will have to stay in the drawer for a little longer, no way am I touching it ! I marvel at the skill that Christian has, so I will restrict my dabbling to the cleaning the cases and changing the crystal. Super photos !

    • Hi Roger.
      Tissot and Omega was under the same umbrella already back since 1930. The bumper automatics do have a lot in common between the two brands. I do not know if the same persons designed both the Tissot 28 and the Omega 28.10RA (basis of this 351), but it very much looks that way.

  3. A nice, honest piece. Omega.. automatic… enough said 🙂
    Need to add a 351 to my collection as well.

    Anders, are you based in Oslo?

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