The first thing to know about watches is that all of them – fancy or plain, expensive or cheap – fall into one of two categories: quartz or mechanical. There are two major differences between them.
Difference number one: A quartz watch uses as its regulator – the device responsible for keeping time – a tiny tuning-fork-shaped piece of quartz (which is how quartz watches got their name). A mechanical watch uses as its regulator a tiny wheel called a balance wheel and a spring called a balance spring or hairspring.
Difference number two: A quartz watch is powered by electricity. A mechanical watch is powered by a mainspring.
Quartz watches are by their very nature more accurate than mechanical ones. That’s because a quartz crystal is a better regulator than a balance wheel. Quartz crystals and balance wheels both measure time in the same way – by oscillating, or vibrating, at a constant rate. A quartz crystal oscillates faster (32,768 times a second) than a balance wheel (28,800 times an hour in most mechanical watches). The oscillations aren’t just faster, they’re also steadier. Both factors contribute to quartz’s superiority as a timekeeper.
The result: An average-quality quartz watch will gain or lose no more than 10 seconds a month. An average-quality mechanical one will gain or lose perhaps five or 10 minutes a month. (Incidentally, one quick way to tell a quartz watch from a mechanical one is to observe the seconds hand at it turns. If it moves in one-second jumps, the watch is quartz. If it moves smoothly, it’s mechanical.)
Quartz watches are more plentiful by far than mechanical ones. Last year, 94% of the watches imported into the U.S. were quartz watches. Just 0.3% were mechanical ones. (The remaining 5.7% were a mix of both – pocket watches and stopwatches that the U.S. Commerce Dept. did not classify by movement type.)
Quartz watches have three ways of showing the time. Some do so digitally by giving a numerical LCD (liquid crystal display) readout. They’re called digital watches. Others do so with hands moving around a dial. They’re called analog quartz watches because the rotation of the hands corresponds to, or is an analog of, the rotation of the wheels in the watch’s movement. The third type of quartz-watch display is called an anadigi. It combines both analog and digital displays on the same face. Often, the digital readout gives one type of information – elapsed time, for instance, if the watch has a chronograph, or the time in another time zone – while the analog display gives the “regular” time.
Most quartz watches run on batteries. They need to be replaced occasionally. Exactly how often depends on the watch and the battery. Some special long-life lithium batteries, which can only be used in watches designed to accommodate them, will last for a decade. The average life for a silver oxide watch battery, the type of battery used in most watches, is two to three years. Only a professional watch repairer should change a watch battery. Do-it-yourselfers can damage their watches.
Some quartz watches don’t need batteries. They’re powered in one of two ways, by light or by the motion of the wearer’s arm. In a light-powered quartz watch, light enters the watch through a special panel, often the watch dial itself, which is designed to be light permeable. A solar cell beneath the panel or dial converts the light, either sunlight of artificial light, into electricity.
The other type of no-battery quartz watch is sometimes referred to as a motion-powered quartz watch. It’s equipped with a tiny rotor that spins in response to the normal motions of the watch-wearer’s arm. The rotor generates electricity to power the watch.
The past few years have brought major improvements in motion-powered and light-powered watches, especially in their energy efficiency. Once fully charged, some light-powered models will run for five years without further exposure to light. Many motion-powered ones will run for 6 months. Some feature a special “sleep mode,” which enables them to keep time for four years without being moved an inch. In sleep mode, the hands don’t move. They turn to the correct time automatically when the watch is given a few shakes.
Now, on to the second major category of watch, the mechanical watch. It comes in two basic varieties. The more common one is the automatic, or self-winding watch. An automatic is equipped with a fan-shaped rotor, or oscillating weight, which turns in response to the motions of the wearer’s arm, the same way the rotor on a motion-powered quartz watch does. The turning of the rotor winds the watch’s mainspring. On many automatic watches the rotor is visible because the watches have transparent case backs, sometimes called display backs or exhibition backs. The rotors are often engraved or otherwise decorated.
If an automatic watch is worn every day for 12 hours or so (assuming the wearer isn’t an inveterate couch potato) it doesn’t need to be wound. If it’s left unworn for a day or two, it will stop running because the mainspring will unwind. (Some automatic watches will run for a week or more, but they’re real rarities.) The wearer can get the watch going again by winding it with the winding crown, the same crown that’s used to set the time. Although the watch will often start if it’s simply shaken a few times, it won’t run very long and it will probably run slow. It needs crown winding. (By the way, over-winding a watch is not the danger some people believe. Mechanical watches are equipped with devices to prevent damage from over-winding.)
Some owners of automatic watches keep them on watch winders when the watches aren’t being worn for a day or more. The winders, which have cups or holders to which the watches can be attached, rotate the watches at regular intervals, keeping the rotors turning so the mainsprings remain wound. They save the watch owner the trouble of winding and resetting the watch (resetting can be a nuisance with some calendar watches) when he wants to wear it.
The other type of mechanical watch is the manual-wind or wind-up watch. It has no winding rotor; the owner must wind the watch in the traditional manner, using the winding/setting crown, usually at the 3 o’clock position.
All mechanical watches need to be taken to a watchmaker every few years to have their movements cleaned and re-lubricated. Recommended service intervals vary from manufacturer to manufacturer, but they’re generally between three and five years. A watch owner should be aware that taking his watch to a repair shop not authorized by the watch’s manufacturer might invalidate his warranty.
As we’ve seen, mechanical watches have certain disadvantages compared to quartz ones. Even so, they’re highly prized by some watch customers who appreciate their old-fashioned technology. In fact, some watch connoisseurs buy only mechanical watches – they believe quartz ones just don’t have the old-world craftsmanship they seek.
Mechanical watches tend to be luxury items. Most are priced at more than $1,000, although less expensive models are available. Quartz watches, on the other hand, can be had for under $10 (mass merchandisers such as Kmart sell many inexpensive quartz watches). The sky’s the limit for the most expensive gem-laden quartz models.