Precision

Precision is not a generic quality: it is the measurable result of design choices that accumulate on an infinitesimal scale. In mechanical movements, every tenth of a millimeter—sometimes every hundredth—changes how the system behaves. This is what distinguishes a mechanical watch from any other object built by mankind: the number of interdependent technical constraints that must coexist in a tiny space.

The industry's starting point is COSC certification. The Contrôle Officiel Suisse des Chronomètres, founded in 1973, accepts movements with a daily variance between -3 and +6 seconds. It is a serious standard, but over time it has become the floor. Rolex introduced its Superlative Chronometer Certification, more restrictive: -2/+2 seconds per day, verified on the assembled watch. Omega went further with the Master Chronometer METAS—born in 2015 with the Globemaster—which certifies precision within 0/+5 seconds per day, magnetic resistance up to 15,000 gauss, and reliability across multiple positions. The Tudor MT5601-U follows the same protocol. These are certifications that measure complete systems, not merely movements in the laboratory.

From my workbench, I have learned that movement precision depends on at least three variables that are difficult to control together: the consistency of force transmitted by the mainspring, the stability of the balance wheel under external stress, and the regulator's ability to ignore gravity. Each has its technical solution. The remontoir d'égalité—used by F.P. Journe and Lederer in the Central Impulse Chronometer—equalizes force to the escapement regardless of mainspring state. The free-sprung balance, regulated with screws rather than a fixed hairspring, offers superior stability through temperature and positional changes. The tourbillon, invented by Breguet in 1801, encloses the escapement and balance wheel in a rotating cage to neutralize gravity's effect—most effective in pocket watches worn vertically. The tri-axial tourbillon, like the one in Desder's D001 designed by Luca Soprana, extends the principle across three simultaneous axes. Breguet's Experimentale 1 pushed frequency to 10 Hz: disturbances and shocks have less time to alter the oscillator between vibrations.

Balance wheel frequency is a direct factor: 28,800 beats per hour (4 Hz) is the modern standard in quality automatic movements. Higher frequency means finer time subdivision, but also greater energy consumption and wear. The seconds-stop mechanism—traditional in pilot watches—allows the movement to be synchronized to the exact second during regulation. A small thing, but practically useful. Horological metrology—the science of measurement applied to movements—has been refined by technologies like Dual Metric Technology, which continuously reads frequency variations with high resolution. Tools like this transform the quality of regulation, not merely its speed.