Repair + Service: Louvic Jump hour watch / Unitas 560

IMG_0944Of all the jump hour watches I’ve seen so far, this is definitely one I would wear. This Louvic has a great case and dial!

Jenny sent it in, and it doesn’t work at all. It’s fully wound, but doesn’t beat.IMG_0946

Inside lurks a Unitas 560, which has been modified for the jump hour mechanism.IMG_0954

I start off by taking apart the gear train.IMG_0958

The mainspring is too short, and somebody has just bent over the broken mainspring to fix the watch, rather tan putting a new mainspring in. The barrel lid is also bent and will need reshaping.IMG_0960

With the second wheel removed, you can see the minute and hour wheel.IMG_0963

The jump hour mechanism has a very unusual construction. Normally, you would just have a single tooth on the centre wheel that would advance a wheel with 12 teeth on the hour wheel every hour. That is of course not an entirely snappy affair, but how it’s done in other jump hour watches. This one has a spring holding the hour wheel in position (at the 8 o’clock marker) that engages with a tooth on the hour wheel. On the centre of the wheel, a spring builds up the tension on the hour wheel, which is released through a little notch on the minute wheel (at about 19 minutes in the previous photo). When the spring looses its tension with time, the change gets a bit sluggish, and there isn’t much you can do. The spring can’t really be made more powerful again.IMG_0973

With all the parts clean, I can start putting the movement back together.IMG_0976

The base movement is beating again with a new mainspring.IMG_0977


Great performance from a movement this age!IMG_9005

I sweat a good three hours over the jump hour mechanism. If released too early, the hour wheel doesn’t change over quickly, and with the release a bit too late, the watch can jump two hours.

Next time, I will be able to do this in 10 minutes 😉IMG_9007

I case the movement and close the back with a new gasket.IMG_9008Great little watch!


13 thoughts on “Repair + Service: Louvic Jump hour watch / Unitas 560

  1. Great, as always. I have to e same one, but the jump hour spring is broken. Any idea who might carry a replacement? No e of my usual suspects can help… Many thanks in advance.

      • Hours of fidgeting later… and I have the spring installed. The hour isn’t exactly jumping over as it should, so more tweaking required, I’m afraid. I will let you know when I get there. Many thanks for your reply!

  2. I removed the “hands” on my Louvic to replace the stem and clean out the gunk from the keyless works, but I’m having trouble getting the wheels right. It seems so much pressure builds prior to the hour jump that the watch stops. Did you grease the wheel or leave it dry?

  3. So, what was the trick that will allow you to make the jump hour spring adjustment in only 10 minutes next time? Must’ve been a doozy!

    • It’s getting the point right at which the hour wheel spring is released by the minute wheel. I just had to get my head around the problem of the watch jumping 2 hours at a time on occasion, and once I had susses how the whole thing works, it was easy enough to sort out.

  4. I have a jump hour watch of the stock kind. I always think that they are more about quirkiness/design over anything else as in truth to me they are quite ugly things.
    They remind me of a daewoo I used to own. It uses parts from other known manufacturers with the result of looking like something familiar but not quite right.

    Having said that I do like wearing mine and it is well worn and in need of service.

  5. An unusual looking thing – more so for not having the manufacturers name on the dial, or at least not that I can see?

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