Horological Machine N°4

Overview

The streamlined, faster-than-sound looking HM4 ‘Thunderbolt’ stretches horological art to its very limits. Both the aviation-inspired case and the engine inside have been described as radical, even anarchistic!

The HM4 engine is the culmination of three long years of intensive development. Each of the 311 components was developed specifically for this calibre. Horizontally-configured dual mainspring barrels drive two vertical gear trains, transferring power to the twin pods indicating hours and minutes on the right, power reserve on the left. With the dials perpendicular to the wearer’s wrist, HM4 might be described as the perfect pilot’s watch.

Horological Machine N°4

What's so special about this machine?

A radical case design, an unconventional engine architecture and sapphire crystal to reveal its engine, the HM4 has been awarded the prestigious Concept & Design Watch prize at the Grand Prix d'Horlogerie in 2010.

Horological Machine N°4

Machine in action

HM4 is not a traditional wristwatch.

The aviation-inspired case and engine of the HM4 are one. Neither would, nor could, exist without the other, yet each is so transcendental as to be able to stand alone as a work of art in its own right.

Horological Machine N°4

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Horological Machine N°4

THE MACHINE

The sleek aerodynamic form of Horological Machine N^o4’s envelope has its roots in Maximilian Büsser's childhood passion for assembling model plane kits, though none looked remotely as futuristic as these.

The striking transparent sapphire section of the case requires over 185 hours of machining and polishing to transform an opaque solid block of crystal into a complex, exquisitely curved panel allowing the light to come in and the beauty of the HM4 engine to stand out. Every component and form has a technical purpose; nothing is superfluous and every line and curve is in poetic harmony. Articulated lugs ensure supreme comfort. Highly legible time is a fringe benefit.

HM4 Thunderbolt in grade 5 titanium and sapphire crystal
HM4 Razzle Dazzle and Double Trouble in riveted titanium and sapphire, with hand painted nose art
HM4 RT in 5N red gold, grade 5 titanium and sapphire crystal
HM4 Final Edition in blackened titanium and sapphire crystal
Dimensions: 54 x 52 x 24mm

Three-dimensional horological engine developed with Laurent Besse and Beranger Reynard
Manual winding with two mainspring barrels in parallel
311 components / 50 jewels / 72h power reserve

Five sapphire crystals: 2 x dials, 1 x central case section, 2 x display panels (top and bottom)

Hours and minutes on right dial, power reserve indicator on left dial
Separate crowns for time setting and winding

Horological Machine N°4

Machine Manual

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Horological Machine N°4

Discover the models available for this collection

Horological Machine N°4

Inspiration

The aviation-inspired case and engine of HM4 come directly from Maximilian Büsser’s childhood passion for assembling model aircraft.

Starting with the original HM4 Thunderbolt in high-tech titanium, the HM4 ‘Razzle Dazzle’ and ‘Double Trouble’ limited editions took the aviation theme even further – with real rivets in their fuselages and hand-painted nose art inspired by the rebellious paintings on WWII aircraft. The HM4 RT offered an altogether more luxurious way to fly, while the iconic F-117 inspired the HM4 Final Edition, featuring square angular panels and stealthy dark surfaces.