A history of precision
From its earliest days, Rolex has sought to have the performance of its watches validated by an official, independent body. Today, 100 per cent of Rolex Oyster Perpetual watches are officially certified as chronometers by the COSC (Contrôle Officiel Suisse des Chronomètres), the official Swiss chronometer testing institute. To receive a chronometer certification, a watch must demonstrate extreme precision in a variety of positions and temperatures during 15 days and nights of testing. Only 6% of all the watches produced in Switzerland are certified chronometers. At Rolex, it is the standard level of quality for all our watches.
CHRONOMETER VS CHRONOGRAPH
A “chronometer” is a high-precision watch, tested for 15 days and 15 nights in different positions and at varying temperatures, and whose performance has been certified by an independent official entity such as COSC (Contrôle Officiel Suisse des Chronomètres).
A “chronograph” is a watch equipped with an additional mechanism to measure short periods of time with start, stop and reset functions. A chronograph can also be certified as a “chronometer”, which is the case of the Rolex Cosmograph Daytona.
The guardian of time
In a mechanical watch, the oscillator is the guardian of time. Comprising a hairspring and a balance wheel, this regulating organ determines the precision of the watch by the regularity of its oscillations. Rolex deploys exceptional know-how and resources to master the design and production of this strategic couple.
After five years of research, Rolex created and patented the blue Parachrom hairspring. Crafted from a paramagnetic alloy, it is unaffected by magnetic fields and up to 10 times more resilient to shocks than traditional hairsprings. Historically, the unique blue colour of the hairspring has been a sign of prestige reserved for only the most accurate timepieces.
The key to time
Have you ever wondered why a mechanical watch goes “tick-tock”? The ticking is produced by the escapement, a strategic part that plays a key role in the movement’s measurement of time. “Tick”: a tooth of the escape wheel locks against one of the pallets of the lever. Then, released by the sweep of the oscillator, the pallet fork lets the wheel “escape”, until it locks against the second pallet: “tock”.
The pallet fork continues its infinite pendular beat against the oblique teeth of the escape wheel precisely 28,800 times every hour – 14,400 “ticks” and 14,400 “tocks”. That's 250 million times a year. We are at the very heart of the Rolex Perpetual movement, where its pace is distilled with chronometric precision.