Automatic watches are hot in the United States. Between 1993 and 1995, U.S. imports of Swiss luxury automatics jumped 95%. Just what are automatics? How do they work? How accurate are they? How often should they be serviced? For answers to these and other questions, read on.
1. What is an automatic watch?
An automatic is a mechanical watch whose mainspring is wound as a result of the wearer’s arm motion.
2. Is that the same as a hand-wound watch?
No. Hand-wound is a mechanical watch that the wearer winds by turning the crown by hand.
3. Why do they call it “automatic?”
Because instead of the wearer having to wind the watch to generate power, the watch winds itself “automatically” when worn.
4. What is the difference between an automatic and a self-winding watch?
Nothing. The terms are synonymous. Self-winding means that the watch winds itself.
5. Is that the same thing as a “perpetual” watch, like a Rolex Oyster Perpetual?
Right. Rolex refers to its automatic watches as “perpetuals.” Automatic, self-winding and perpetual all mean the same thing: the watch winds itself. (A perpetual calendar, however, is something else.)
6. How does an automatic watch work?
The movement of the wrist and body causes the rotor, a metal weight attached to a winding mechanism, to pivot freely on its staff in the center of the movement. The rotor rotates back and forth in a circular motion at the slightest action of the wrist. The rotor’s movement winds the mainspring, a flat coiled spring that powers mechanical watches.
7. How accurate are they?
Mechanical technology, by definition, is inferior to the extreme accuracy of an electronic watch. Automatics are plenty accurate for normal daily timekeeping, though. A normal automatic is accurate to within +30/-5 seconds a day, depending on the quality of the movement.
8. How much motion does an automatic need to work properly?
A person’s normal arm and wrist motion will keep an automatic watch properly wound. People who are inactive—the elderly or patients confined to beds—may need to wind their watch to keep it powered.
9. Is it safe to wind an automatic watch?
Sure. Winding the watch won’t hurt it at all. If you haven’t worn an automatic in a while, it is best to wind the stopped watch before putting it on. Ten to 15 turns of the crown is usually enough to give full power to the mainspring.
10. How long will an automatic watch keep turning off the wrist?
That depends on the type of movement in the watch and how much power is left in the mainspring when you take it off. A normal, fully wound automatic movement will keep running from 36 to 48 hours. Bernhard Stoeber, vice president of technical services at the Movado Group, recommends winding an automatic watch when one takes it off so that it will keep running as long as possible when not worn.
11. How often does an automatic need to be serviced?
Most companies recommend the watch be checked and relubricated every three to five years. If the wearer regularly subjects a water-resistant automatic to water, the seals should be checked annually.