When to Service a Mechanical Watch?

Sooner or later a mechanical watch will need to be serviced. If you’re collecting watches for a while or you’re part of an online watch community there’s a good chance you already know this.

These are the common views on servicing a watch:

1. A mechanical watch needs to be serviced every 5 or 6 years.
2. A mechanical watch only needs to be serviced when it’s starting to run fast or slow.

Why do you need to service a mechanical watch?

A movement and especially a mechanical movement consists of many different parts.

To function properly these parts need to be in good condition. Furthermore, they need to be clean and some parts need to be lubricated in a certain way.

Over time, the lubrication might dry out, thicken or filth and dirt might build up. These are all things you need to avoid to keep your watch in tip-top condition.

What does a service look like?

• A watchmaker will start by completely disassembling a watch.
• All the parts will be cleaned in an ultrasonic cleaner or in the watch cleaning machine.
• The watchmaker will check the parts for any wear or tear and worn parts will be replaced.
• The movement is put back together and lubricated with the correct oils and greases.
• The watch/movement is checked for magnetism and if needed, it’ll be demagnetized.
• The watch will be wound for a test run and observed for a period of, let’s say 24 hours.
• Finally, some last fine-tuning and regulating and it’s ready to be worn and treasured again.

When to service a mechanical watch?

Most popular modern oils ( Moebius 9010/9020, 9415, etc.) have a shelf life of 6 years. Moebius D5 has a shelf life of 3 years but Moebius HP1300, the recommended replacement, has a shelf life of 6 years as well.

So, Moebius (part of the Swatch group) advises servicing a vintage watch every 6 years. That seems rather excessive though. You can imagine why it would be of interest to the Swatch group to promote a low service interval.

I’ve seen watches that were perhaps 10 years old that needed a full service and several parts to make it run properly again. I’ve also seen a lot of watches that were never serviced (or perhaps decades ago) but were still running well after all those years.

In my experience, the quality of the movement has more influence on the amount of wear than the service interval.

Inspection

What I personally do, is I inspect the movement and especially the balance and its shock protection. After a service, the capstones of the shock protection are oiled to lubricate the pinions of the balance staff. When you look at the upper capstone of a recently serviced watch with magnification you can see a tiny bubble of oil.

Regulator

I also look at the position of the regulator index and place the watch on a timing machine to determine the rate of the watch, the amplitude, and the beat error. If the regulator index is in the middle it tells you that the watch runs steadily without needing much compensation.

If the regulator index is heavily towards the “slow” side ( S for slow and R for retarder) it tells you that the movement runs too fast and heavy compensation was needed to keep the time. Of course, the same is true if it’s towards the “fast” side although that happens much less.

If the beat error is too high, the amplitude is too low or the rate is too high or low in combination with the position of the regulator index, it needs a service. Otherwise, it doesn’t.

If you don’t have the tools to measure its performance or you’d rather be safe than sorry, it can never hurt to follow Moebius’ advice on when to service a vintage watch.

Do you have any tips or questions? Leave them in the comments below.

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