How mechanical Watches work
Left unchecked, this mainspring would quickly unwind and give up its energy in an instant. Therefore, the barrel that houses the mainspring is meshed 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 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. But 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 was 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 sure death.
All Wound Up
One of the beautiful things about a mechanical watch is that is requires interaction with its owner to function. That coiled mainspring will only provide power for a day or two (or sometimes longer) if you don’t keep it wound. A handwound watch is the purest form of the mechanical timepiece, which is part of its appeal. The mainspring is wound, as the name suggest, by turning the watch’s crown a few dozen times. While winding a watch is a simple process, there are a couple things to be aware of. First of all, wind the watch off of your wrist. While it may be tempting to give the crown a few twirls while you’re surfing the Web at work, the angle can be awkward and put lateral stress on the delicate winding stem. Secondly, don’t overwind your watch. You’ll know when it’s wound when you can’t turn the crown anymore. This isn’t like topping off your gas tank, so don’t try to give it a little extra. Stop winding when you first feel resistance. Try to wind your watch once a day. A watch typically keeps best time when the mainspring is above half tension. The typical watch has about a two-day power reserve so winding it up before you strap it on each morning is a good habit to form.(Hand) Winding Rules
1. Wind the watch off your wrist to minimize stress on the winding stem.
2. Don’t overwind. Stop when you feel resistance.
3. Make a habit out of winding your watch every day before you strap it on. If it’s an automatic, just strap it on.
The automatic, or self-winding, watch, functions as its name suggests. As long as you’re wearing it, the mainspring maintains tension thanks to the weighted rotor in the movement that oscillates with your arm’s movements. A slipping clutch prevents the spring from getting overwound. Unless you don’t wear your watch daily or you’re an extremely inactive person, you won’t have to wind your automatic. But if you do, just give the crown 20 or 30 spins until the seconds hand starts moving, set the time and then strap it on. Unlike the handwound watch, you can’t overwind your automatic, but don’t overdo it — the winding mechanism in an automatic is typically less robust than that in a handwound watch and thus more vulnerable to breaking with careless or excessive use. Let the watch wind itself. And if you don’t wear it regularly, invest in a quality watch winder.
Setting a watch is a pretty straightforward process, but it does have some dos and don’ts. The most important rule is not to set the date if the watch’s time is between 9 p.m. and 2 a.m. Note that we said “the watch’s time”, not the actual time of day. If you pick up a watch that isn’t running and you aren’t sure when it stopped, pull the crown all the way out and spin the hands until the date changes. Then you’ve found midnight; next, advance the time past 2 a.m. before pushing the crown in to set the date. Why, you ask? The date-changing mechanism starts to engage the gear train after 9 p.m. and only disengages after 2 a.m. Setting the date during this period can break off the delicate teeth of the mechanism, resulting in a costly repair. It’s also a good idea to set a watch forward rather than running it backwards. This is, again, to prevent damage to the date mechanism. Of course, if your watch doesn’t display the date, none of this matters.