Congratulations, you bought your first mechanical watch. That makes you the rightfully proud owner of more than just a timekeeper: that little disc on your wrist is an emblem of the culmination of art and science, a salute to man’s ingenuity. Whether you wear it just for special occasions or it accompanies you during all of life’s significant moments — and whether you paid a week’s salary for it or a year’s — it should serve you well, running trouble-free for many years. Set it and forget it. Strap it on and go. These are the pros of a mechanical watch.
But before you reap the benefits, there are a few things to keep in mind that will help keep that watch running flawlessly until you pass it on your offspring one day. Take some time to learn them thoroughly. Your timepiece deserves it.
How a Mechanical Watch Works
The basic architecture of almost every mechanical watch for the past three centuries is the same, proving what a truly ingenious and efficient machine it is. Unlike a quartz watch, a mechanical timepiece doesn’t get its energy from a battery. Instead, the power that drives the hands around the dial, and also drives any additional complications like a date function, a moonphase or a chronograph, comes from the unwinding of a tightly coiled flat spring.
Left unchecked, this mainspring would quickly unwind and give up its energy in an instant. Therefore, the barrel that houses the mainspring meshes with a precisely-sized geartrain of toothed wheels that terminates in what is called the escapement. The escapement consists of a wheel that is caught and released intermittently by a pivoting lever. The pivoting of the lever is controlled by a delicate spiral aptly known as the hairspring. This so-called “lever escapement” controls the energy release from the mainspring, feeding back this power through the geartrain, driving the hands of the watch to count out seconds, minutes and hours.
The hairspring is the heart of the watch; if you’ve seen a mechanical watch movement running, you’ll appreciate that metaphor, as the hairspring “beats” back and forth at a steady rate anywhere between 18,000 and 36,000 times per hour. The precision of the watch depends largely on the tension of this hairspring, as well as its resistance to temperature changes and magnetism. Most modern hairsprings are made up of a metallic alloy that compensates for temperature changes, and some are made from silicon, which is immune to magnetism.
With all of these meshed gears and delicate springs, it’s a wonder these contraptions are as precise as they are (though a well-adjusted chronometer-grade movement can keep time to a 99.999% accuracy). But, as you might guess, friction and external shocks are archenemies of the mechanical watch movement. Friction is mitigated by regular lubrication and smooth “jeweled” bearings. Those red shiny discs you see in the bridges of a watch are rubies, formerly real ones, currently most often synthetic ones. The pivots of the gear wheels ride in the center of these rubies, which are polished smooth to provide nearly frictionless surfaces.
If there were no wiggle room for those delicate pivots, a sudden jolt from say, your arm scrambling eggs, could shear one off, a death blow to the movement. So the jewels are suspended in a floating frame that absorbs vibrations and shocks, saving the pivots from certain death.