Mechanical watches have been keeping time since the 17th century, and with that long history comes the impression that they simply run forever. Unfortunately, this isn’t always the case. A mechanical watch is an engine, and like the engine in your car, it needs to be cleaned, oiled and adjusted (COA) on a regular schedule to function at their best.
Watch servicing is actually less complicated than many people would think. All that is required is a very steady hand, the ability to work calmly under magnification and the right tools to make sure that the watch movement is not damaged in the process.
How often should I have my watch serviced?
This can be a hard question to answer, but you can treat it like you do your car. Most mechanical watches should be serviced on a standard five year schedule. With normal wear this is how long it takes for oils in your watch to break down or dry up or for enough dirt to collect in your watch to require a thorough cleaning.
Another indication that it is time to service your watch is that it stops keeping accurate time. This is most often seen in a watch that runs slow regardless of how well wound it is. Let’s look at a quick overview of what goes in to a COA.
Taking the movement apart
Warning: you can easily ruin your watch forever if you are not experienced or careful in how you disassemble and reassemble your watch movement.
When it is time to service your watch the first step is to disassemble it. We start by releasing the tension on the mainspring. Once that is done we can remove the crown and stem. The movement will then come easily out of the watch case in most instances. The watch is then turned over so that the hands may be removed.
Once the hands are removed we again turn the movement over and locate the screws or dial feet that hold the watch face in place. Carefully the screws are removed and the watch face is removed without bending it. On the front of the movement we can now remove the minute and hour gears and pinions.
Finally we can begin the process of removing each gear and spring from the movement. Each piece must be treated with extreme care and keep secure for reassembly.
Cleaning and oiling the movement
Now that the watch and movement disassembled it’s time to clean it. Each part of the movement and the watch case are cleaned thoroughly in either an ultra sonic cleaner, or a naptha solution may be used. If you choose to use naptha, please be very careful, this chemical is toxic and can harm you if not used properly. Once the parts are cleaned, allow them to dry on a lint free cloth or paper towel. Any lint or dust you introduce to the movement at this point will defeat the purpose of cleaning it.
Once all of the watch parts are cleaned it is time to oil. When oiling a movement there is a very fine balance between using enough oil to provide lubrication and using too much oil and having it attract dust and creating a mess inside the watch. Very little oil is actually needed since only very small drops are placed on each jewel or pivot hole. One area you want to avoid getting oil on is the hairspring. The oil will cause the spring coils to stick to each other and keep the watch from functioning properly.
Reassembling the watch
Now that the movement has been properly cleaned and oiled its time to put the watch movement back together. The process is simply the reverse of disassembly. However, extreme care needs to be taken. Each gear should easily slide in to place and the screws that hold them should tighten easily. Any binding or tightness needs to be address immediately or the watch will most likely not function properly.
Once the movement is reassembled we can replace the dial and the hands and then place the movement back in to the cleaned watch case.
As you can see, there is a lot that goes in to servicing a watch and a lot that can affect the time and skill required. I am very comfortable taking apart a simple mechanical watch, but as the complexity of design increases I become less and less confident. Even after taking watch repair classes from people like Dan Gendron, now retired, I find myself looking in to these watches and marveling at the complexity. tag heuer repair