It’s hard to believe that something so small and compact that it fits on your wrist can have an entire system of parts and movements. But such is the case with a mechanical watch.
A mechanical watch is a watch that is not powered by a battery, but by the energy stored in a coiled-up spring. How that energy moves inside the battery to cause the minute and second hands on the face to turn is surprisingly complex, and yet genius in its cleverness. There’s a reason this precise system has been with us, in one iteration or another, for centuries.
If you’ve ever wondered how a mechanical watch works, reading this brief guide will turn you into an expert in no time.
First, here are the basic parts that make up a typical mechanical watch.
The mainspring is the energy source of the mechanical watch. It’s a thin, tightly coiled spring consisting of steel ribbon.
The winding mechanism consists of a set of gears called the keyless work which winds up the mainspring. You can activate the keyless work by turning the knob outside of the watch. The knob, by the way, is called the crown. Turning it will increase the mainspring’s energy again after the watch has been in use for a while.
The gear train is a series of gears that transfer energy from the mainspring to the escapement. The first and fourth wheels also control the minute and second display hands, respectively, on the face of the watch.
The escapement is a system with two parts: an escape wheel and a pallet lever. The pallet lever looks sort of like a tuning fork, and the teeth on the escape wheel catch on the two arms of the lever as it turns back and forth.
The Balance Wheel
The balance wheel is a weighted wheel with a jewel in the center. It oscillates and, in doing so, triggers the pallet lever, so that it moves the escape wheel back and forth. This way, the escape wheel will never stop moving, but it also only moves at a controlled rate.
The display hands are visible on the face of the watch. They tell you the time in minutes and seconds.
Now that you know the different parts of a mechanical watch, here’s how they work in tandem to produce the watch’s movements.
First, the mainspring is wound using the winding mechanism. Next, the energy from the mainspring is transferred through the gear train to the escape wheel. The escape wheel and the pallet lever prevent the energy from escaping all at once by forcing it to slow down. This works because the teeth of the escape wheel catch on the ends of the pallet lever.
Meanwhile, the force of the escape wheel against the pallet lever causes the balance wheel to oscillate, creating the ticking sound we’re all familiar with. This motion causes the pallet lever to oscillate, as well, which turns the escape wheel in a back-and-forth motion. This sends energy back out into the gear train and turns the first and fourth wheels to keep time.
That’s how a mechanical watch’s movements work. Knowing the process will doubtless help you appreciate both your watch as well as horology itself to an even greater degree.