(Not) Adjusting a Russian ZIM 2602 Wristwatch

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The world of watch collecting is wide: no kind of watch is so odd that it doesn’t have a passionate community of people arguing about it on an Internet forum, especially if that forum is Watchuseek and the watch is made by Seiko or Invicta.

Russian watches are a quirky side of the watch world with their own quirky forum. Russian watchmaking has an interesting history, one bound up with technology, politics, finance, and the inimitable style of Eastern European watches.

I picked up this little watch—a ZIM 2609 wristwatch—as part of a big batch of watches. The dial has a nice patina as well as many scuffs and scratches from careless attempts to remove and replace the hands.

I’ve been honing my ability to refinish and repair watch cases. If you ever need a big batch of practice watches with crappy cases, eBay has hundreds of dingy and unloved Russian watches awaiting your attention.

And as hoped, this watch’s case looks like it got dragged behind a Soviet tank. It is chrome plated brass, with deep nicks, lots of scratches and corrosion, and extensive plating loss.

The ZIM 2602 is a quirky watch, even by the standards of Russian watches. For one, it has an actual overcoil hairspring, a rarity among Russian watches. To this day, Russian watches typically have flat hairsprings with regulator pins.

Also, this watch has some pretensions to decoration. Note the striping on the bridges and the finish on the winding wheels.

Most Russian watches have a simple frosted or grained finish. After all, in 1950s Russia, no one but your watchmaker and the neighbor informing on you would ever see the inside of your watch.

But the finishing really is superficial. This is a rough watch.

Consider, for example, the cap jewel screws. These screw in from underneath, and the tips are poking out. In a nicer watch, the screws would be the same size, for one, and they would be flush with the cap jewel. The screws’ ends would be also polished and rounded, giving them an attractive domed appearance. These screws, though, simply stick out.

Ugly or not, this watch was easy to service—just a basic hand-winding movement. The old mainspring was set, so the watch got a new white alloy mainspring and several vigorous demagnetizing trips. You can still get new mainsprings for this caliber. (A ZIM 2602 takes a Generale Ressorts GR3996DB, if you’re working on one.)

Right off the bat, the amplitude was huge and the timing traces were clean, so I let the watch sit for a few days to break in and unwind (literally).

Servicing and Adjusting the Watch

I wasn’t sure what sort of accuracy standards for adjusting to apply to this watch. On the good side, the amplitude is huge in all positions and the timing traces were clean.

On the other side, this is an old Russian watch. Enough said—except for a few notable models, Russian watches won’t be winning any accuracy contests. They are rough and rugged and easy to service, but this watch looks bad compared to the American and Swiss watches of the time. And a watch like this has been kicked around Eastern Europe for half a century.

So, what we’re the rates like?

Way Wavy Traces

Oh boy. These were some wavy, wavy traces. In an earlier post, we explained that stable rates were required for adjusting. Basically, the rates should be stable over short time intervals. When they are, they look like railroad tracks—straight and parallel. If a watch’s rate moves around—+10 at one point, and -10 the next minute—it can’t be adjusted because you can’t pin the rate down.

This little ZIM had seriously unstable rates. Here’s what it looks like in the pendant down (PD) position, one of the 3 main ones forĀ  wristwatch.

The screen captures around 40 seconds, so the rates vary a lot within this period. And here’s what we see a couple minutes later.

It’s worth noting that the rates were more stable dial-up and dial-down. The huge amplitude in those positions gives the balance wheel more momentum and makes it more robust to the many minor flaws that cause wavy traces.

In our prior post, we talked about how to diagnose the source of the wavy traces. If the peak of the wave is every 60 seconds, for example, then there’s a flaw in the fourth wheel. For our little ZIM, however, there was no obvious periodicity.

So I took apart the watch and inspected the gears. Most of the wheels had some flaws, and the flaws, when combined, could give the erratic wavy traces that we see.

  • The third wheel had a few rough teeth
  • The fourth wheel was very slightly out of flat, had a few teeth with unusual wear, and had a couple pinion leaves with unusual wear
  • The escape wheel had a couple pinion leaves with unusual wear

This kind of pattern suggests that the gear train got a big jolt at one point. If a mainspring snaps (or is let down roughly by a watchmaker), the gears can jam against each other and get chipped and malformed teeth and pinion leaves.

Wrapping Up the Movement

I’m not willing to repair or replace the gear train, so we’ll write off this little watch as a lost adjusting cause. I regulated it to run a few seconds fast dial up. With its amplitude, it will keep reasonable time in use—accurate enough to evade the police in 1960s Stalingrad, at least.

Most of the watches we’ve covered in this blog have turned out really well, but it’s worth covering the unadjustable watches, too. As all the adjusting books say, adjusting is something you do to make a very good watch great—it can’t compensate for basic flaws in a movement.

And the Case?

Unlike the movement, the case turned out unusually well. But that long and sordid story will wait for a post of its own.