Inside a mechanical movement

The four parts

Every mechanical watch does the same thing. A mainspring stores energy when you wind it (or when the rotor of an automatic winds it for you). A gear train transmits that energy and turns the hands. An escapement lets the energy out in tiny, equal steps. A balance wheel, swinging back and forth at a constant rate, controls those steps. That rate, usually 28,800 beats an hour, is what you hear when you hold a watch to your ear.

Why accuracy is not the point

A good mechanical watch drifts a few seconds a day; a cheap quartz watch drifts a few seconds a month. If accuracy were the point, nobody would buy mechanical watches. The point is that a mechanical movement is a machine made of two hundred tiny parts, assembled by hand, that will run for a century if it is serviced. A chronometer certificate (COSC) guarantees minus four to plus six seconds a day; Rolex’s own standard is plus or minus two.

Finishing: the expensive part

Look at a movement through a sapphire caseback. Bevelled edges polished to a mirror (anglage), striped bridges (Geneva stripes), circular graining on the mainplate, black-polished screws that look either white or black depending on the angle: this is hand finishing, and it is where the hours go. It adds nothing to timekeeping and everything to the price and the pleasure. Patek Philippe, A. Lange & Söhne and Vacheron Constantin are the benchmarks; independents like F.P. Journe and Voutilainen take it further.

In-house, manufacture, calibre

An in-house movement is designed and made by the brand itself. It is a point of pride and a point of marketing. Some of the best movements ever made were supplied by specialists (ETA, Sellita, Valjoux) and finished by the brand. What matters is the quality of the design, the finishing and the servicing network, not the badge.

Complications

Anything beyond hours, minutes and seconds is a complication: date, day, chronograph, GMT, annual calendar, perpetual calendar, moonphase, minute repeater, tourbillon. Each adds parts, cost and service complexity. A perpetual calendar that will not need adjusting until 2100 is a marvel; it is also a watch that needs an expert every five to seven years.

Service

Every five to seven years a mechanical watch needs a service: disassembly, cleaning, fresh lubricants, new gaskets, a pressure test. At a manufacture, expect several hundred to a few thousand dollars depending on the complications. Budget for it; it is the difference between a watch that lasts a lifetime and one that lasts a decade.