Mechanical, automatic, quartz: what actually powers your watch.

There are three ways to make a hand go round at a rate you can trust, and the watch industry has spent four hundred years arguing about which of them deserves your money. Everything you will ever pay for in a watch traces back to that argument. Here is what each answer actually does.

The spring and the escapement

A mechanical watch stores energy in a coiled mainspring that you wind by hand. The escapement, a tiny gate that opens and shuts several times a second, meters that energy out in equal portions, and a balance wheel swinging back and forth sets the rhythm. It is a machine from the 17th century, perfected rather than replaced. It is also why a $500 Hamilton feels alive on the wrist in a way your phone never will.

The rate of that swing is quoted as vph, vibrations per hour. 21,600vph is three swings a second. 28,800vph is four. A faster beat generally means a smoother-looking seconds hand and slightly better resistance to shocks knocking the rate about. A slower beat generally means a longer power reserve out of the same spring, which is exactly the trade Tissot makes in the Powermatic 80 to reach 80 hours.

Neither of those is better in the abstract. They are two answers to the question of what you want the watch to be good at.

Automatic: the rotor’s trick

An automatic is the same machine wearing a flywheel. A weighted rotor spins with the movement of your wrist and winds the mainspring for you. Think of the winder on a wind-up torch, except it never stops turning while you are wearing it.

Nothing about that makes the watch more accurate. It makes it more convenient, and slightly thicker as the fee for that convenience.

Here is the part nobody explains to beginners. An automatic still has a finite reserve. Take it off on Friday night, and unless it banks 70 or 80 hours it will have stopped by the time you want it on Monday. Which is why the reserve figure on a spec sheet is a usability number, not a bragging number.

Quartz: the honest overachiever

Quartz deletes the entire drama and replaces it with a crystal vibrating 32,768 times a second and a battery. It is roughly ten times more accurate than any mechanical movement, at a fraction of the price, and the watch world has never fully forgiven it for that.

Solar quartz, as in Casio’s Tough Solar, removes the last objection by charging the cell from ambient light. No battery changes, no service interval. Radio-synchronised versions go further again and correct themselves nightly against a national time signal, which makes them the most accurate watches most people will ever own by a margin no mechanical movement can approach.

I have no patience for the snobbery here. A movement that does its job for $120 has earned its place on your wrist.

Which one should you want?

If you want the object to be interesting, buy mechanical, and buy the longest power reserve you can afford so the thing is still running when you come back to it. If you want the time to be right, buy quartz and stop reading watch reviews. Most collections end up holding both, for precisely those two reasons.

One term to carry into the next lesson: hacking means the seconds hand stops when you pull the crown out, so you can set the watch to the second. It is cheap to engineer. Its absence on an otherwise good movement tells you exactly where the maker decided to save money.