Skip to main content
Hamburger Menu Close



Million-dollar time machines: An atomic clock that syncs with your wristwatch

Eight years in the making, and with only three pieces in the known universe, Urwerk’s AMC costs a cool S$3.8 million and features an atomic clock plus a wristwatch that can be synced with it.

Million-dollar time machines: An atomic clock that syncs with your wristwatch

The Urwerk AMC. (Photo: Urwerk)

In the world of serious watchmaking, the mechanical and the electrical have always been at opposing ends of the spectrum. Watch purists will argue that only the former can be considered ‘real’ watchmaking and it would be blasphemous if the two elements even come close to one another in a watch.

Thus, high-end watchmakers have mostly steered clear of the latter, instead, preferring to focus on the traditional side of watchmaking. None of them will ever think of somehow combining the two, as the idea of a mechanical/electronic watch at the high-end price point seems rather preposterous. Unless you are Urwerk, that is.

With Urwerk considered the ‘mad scientists’ of the watch industry, preposterous is exactly what they – founders Felix Baumgartner and Martin Frei – are gunning for. The Urwerk AMC is a combination of a mechanical wristwatch and a 35kg watch winder that, by the way, is also an atomic clock (AMC stands for Atomic Master Clock).

The Urwerk AMC is housed in a 35kg metallic monobloc. (Photo: Urwerk)

How the AMC works is similar to Breguet’s Sympathique clock of 1793. The idea is to use a more accurate but stationary base clock to help keep time on the satellite timekeeper (in Breguet’s case, it was a pocket watch), adjusting and regulating it whenever the unit was ‘docked’.

Urwerk took this step one step further. For the base unit – called an Atomolith – Baumgartner and Frei decided to go with the most accurate clock to date, an atomic clock. Not only does the Atomolith (doesn’t the name sound like something only a mad scientist could come up with?) house the atomic clock, it also has a GPS system for synchronisation.

To illustrate just how accurate atomic clocks are, consider this. The Superlative Chronometer certification from Rolex is considered to be one of the best standards for traditional mechanical watches. That has a deviation threshold of +2/-2 seconds per day. High accuracy quartz movements like the Grand Seiko’s Calibre 9F is accurate to +10/-10 seconds per year. The Atomolith offers a deviation rate of 1 second every 317 years. Yeah, pretty hard to beat.

The AMC comprises a wristwatch and a base unit. (Photo: Urwerk)

So how does an atomic clock work? The basic principle of timekeeping hinges on the regulator. In a mechanical watch, it is the balance spring that plays this role and typically oscillates at 4Hz or 28,800 beats per hour. In a quartz watch, the namesake crystal is the regulator and generally clocks in at 32,768Hz.

With an atomic clock, the measurement of the electron transition frequency within an atom becomes the regulator and in the case of the Atomolith, a Rubidium isotope is used. The frequency of Urwerk's atomic clock (made in collaboration with Swiss firm Spectra Time) is a gob-stopping 429,000,000,000,000Hz.

A diagram illustrating how the wristwatch is calibrated. (Photo: Urwerk)

All of this would mean nothing if the atomic clock, housed in a case of solid aluminium, could not communicate with the portable AMC wristwatch. The clever bit is designing the watch so it could be wound, synchronised and have its regulator adjusted without the need to open the watch case.

Urwerk achieves this process by allowing the Atomolith to interact with the AMC via the crown and two additional pushers. Apart from setting the time, this process of interaction between the Atomolith and AMC also adjusts the regulation rate so theoretically the watch will become more precise each time it is docked.

The mobile unit of the AMC offers a 4Hz movement with a Swiss lever escapement and a linear balance wheel with 80 hours of power reserve. Another fun fact: The AMC has an oil change indicator – a feature that Urwerk has used in previous models – which makes a full rotation in a little over four years, signalling to the wearer when it’s time for the watch to be serviced.

READ> Digital disruptions: Fifty years after the quartz revolution, a new era is upon us

Source: CNA/ds