What is an automatic watch?
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An automatic watch is a mechanical watch that winds itself from the motion of your wrist. Inside, a swinging weight called the rotor tightens a mainspring. The spring releases energy gradually through a gear train and an escapement that drive the hands. There is no battery: worn, it runs; set aside, it stops when the reserve runs out.
How an automatic watch works
- The rotor. A half-moon weight pivoting at the centre of the movement. Every movement of your wrist turns it.
- The mainspring. Through gears, the rotor tightens a long thin spring coiled in a barrel: the watch's battery, in effect.
- The gear train. The spring unwinds slowly and turns a series of wheels that divide its force into seconds, minutes and hours.
- Escapement and balance wheel. The heart. The balance swings back and forth at a steady rate and the escapement releases the train one small step per swing. That is the tick.
That is why the seconds hand on a good automatic seems to sweep: it moves in several small steps each second. The NH35A beats 21,600 times an hour, six beats a second. Full NH35A specs.
Power reserve
Power reserve is how long the watch runs from a full spring with no motion. On the NH35A it is about 41 hours: take it off on Friday evening and it will likely still run on Saturday morning; leave it for a few days and it stops. A stopped automatic is not broken. Wind the crown, set the time and wear it. See watch care.
Hand-winding and hacking
- Hand-winding: charge the spring by turning the crown, without shaking the watch.
- Hacking: pulling the crown to the time position stops the seconds hand, so you can set the watch to the second.
The NH35A has both, one reason it is so popular. More terms in the glossary.
Automatic or quartz?
| Automatic | Quartz | |
|---|---|---|
| Power | Wrist motion, mainspring | Battery |
| Accuracy | Seconds per day, depending on movement | Very accurate, typically seconds per month |
| Seconds hand | Sweeps, several steps a second | Jumps once a second |
| Maintenance | Periodic service by a watchmaker | Battery changes |
| When not worn | Stops when the reserve runs out | Keeps running |
| The experience | A small living machine on the wrist | A practical instrument |
Want maximum accuracy with no thought? Quartz. Love the idea of a mechanical movement, the sweeping seconds and no battery? Automatic.
Basic care
- Wear it; automatics like to be used.
- If it stopped, give the crown 20 to 30 turns, set the time and put it on.
- Do not change the date late at night, roughly 9 pm to 3 am, while the date change is engaged.
- Keep it away from strong magnets such as speakers and magnetic bag clasps; magnetism can make it run fast.
- A periodic service by a watchmaker keeps it accurate for years.
The ATÉRET automatic
Every ATÉRET watch is an automatic with an NH35A movement in a 39 mm stainless steel case with sapphire crystal. Choose dial, hands and strap in the 3D builder; it is assembled by hand in Israel. ₪790 to ₪940.
Frequently asked questions
What is the difference between automatic and mechanical?
An automatic is a type of mechanical watch. A manual watch is wound only by the crown; an automatic is wound by a rotor from wrist motion. Many automatics, such as the NH35A, can also be hand-wound.
Does an automatic watch need a battery?
No. It is powered by the mainspring, wound by the rotor as you move.
Why did my automatic watch stop?
Most likely the power reserve ran out because it was not worn; on the NH35A it is about 41 hours. Wind it, set the time and wear it.
How accurate is an automatic watch?
It depends on the movement. The NH35A's published spec is about -20 to +40 seconds per day, and many run better in practice. Quartz is more accurate.
Can you overwind an automatic?
Not a modern automatic like the NH35A; a slipping mechanism prevents the mainspring from being overwound.
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