What Happens During a Full Watch Service
The steps involved in a complete mechanical watch overhaul, from disassembly to timing adjustment.
By Harry · · 4 min read
When you bring a watch in for a full service, you're not just getting a quick oil and a polish. A proper service is a deliberate, methodical job that takes time and skill. I take apart your watch movement piece by piece, clean every component, replace worn parts, reassemble it, and bring it back to working order. It's the difference between a watch that keeps okay time and one that runs reliably for years. If you've got a watch that's been sitting in a drawer or one that's losing time, a full service is usually what it needs.
Why Your Watch Needs a Service
Watches are sealed systems, but they're not sealed forever. Over time, the oil inside the movement breaks down and gets thick. Dust and moisture creep in despite the case back. The balance wheel loses its precision. Mainspring tension fades. If you wear your watch daily or store it for years, you're going to need a service. Most mechanical watches benefit from a service every five to ten years, depending on how much you wear them and how well they're cased. Quartz watches can go longer, but they still need attention eventually. The mainspring will weaken, the battery contacts will corrode, and small parts will wear down.
Taking the Movement Apart
The first step is removing the movement from the case. I work on a proper bench with good light and the right tools. Once the movement is out, I remove the case back, dial, and hands. Then I start disassembly. I work systematically, removing the train wheels, the escapement, the balance wheel, and the mainspring. Each piece gets its own place on my workbench so nothing gets mixed up. This is where experience matters. Some movements are straightforward. Others have complications or unusual layouts that require you to know the design cold. I've worked on everything from basic three-hand movements to chronographs and perpetual calendars.
Cleaning and Inspection
Once everything is apart, every single component goes into an ultrasonic cleaning bath. The bath removes decades of old oil, dust, and corrosion. After cleaning, I inspect each piece under magnification. I'm looking for wear on the jewels, bent pivots, worn teeth on the wheels, corrosion on the balance cock, and cracks in the mainspring. This is where I determine what can be cleaned and reused and what needs to be replaced. A worn balance pivot or a corroded screw can't be saved. A mainspring that's lost its temper has to go. Parts that are fine get set aside for reassembly.
Reassembly and Regulation
Once cleaning and replacement are done, reassembly begins. I rebuild the movement in reverse order, using fresh synthetic watch oil on the pivots and bearing surfaces. The type of oil matters. Different movements need different viscosities. I use the right oil for the right place. Once the movement is back together, it goes into the timing machine. This is where I check the beat rate, the amplitude, and the rate. A watch running fast or slow gets regulated. The balance wheel hairspring can be bent slightly to speed up or slow down the movement. I'm aiming for something close to zero, but real-world accuracy depends on the watch and how you wear it.
Case Work and Final Assembly
While the movement is being serviced, the case and dial get attention too. I clean the case, check the crown and pushers for function, and inspect the crystal. If the crystal is scratched or cloudy, it gets replaced. The case back gasket gets replaced with a new one to maintain water resistance. Once the movement is regulated and running well, I install it back into the case, reinstall the dial and hands, and test everything again. A watch that was losing five minutes a day should now be keeping time within a few seconds a week.
What You Get Back
When you pick up your watch, it should feel different. The movement will be smooth and precise. The crown will operate cleanly. The watch will keep time reliably. If your watch was water-resistant before, it will be again, assuming the case and crown are sound. You'll get a service report that shows what was done, what was replaced, and what the watch is running at now. A properly serviced watch will give you years of good service before it needs another one.
If your watch has been neglected or you're not sure what it needs, bring it in. Watch Repair & Co is here in New York, and I'll take a look at what you have and tell you straight what it needs. Call to set up a time.