MB&F HM4 Thunderbolt watch makes ostentatious debut

Remember the bizarre HM4 Thunderbolt teaser that high-end watch manufacturer MB&F showed us last month?  The company has come clean with the final, official product, and as wrist-watches go this is certainly unusual.  Three years in the making, the MB&F HM4 Thunderbolt is based around the indecently complex HM4 engine and has dual dials – one for the time, one a power indicator – which the company reckon adds up to relative simplicity.  Of course, when your casing resembles a crash between a jet engine and an Italian espresso machine (with a little H.R. Geiger in there for good measure) "simplicity" probably isn't the first description most people would reach for.Video demo after the cut

The two mainspring barrels in the HM4 movement can together store up to 72hrs worth of power and transfer them via vertical gear trains to the indication pods.  Sapphire glass top and bottom means the mechanism is visible, and if you're lucky you might even catch a glimpse of MB&F's "distinctive streamlined cock" which supports the balance.

There are 50 jewels and 311 components in the engine, five sapphire crystals and a black hand-stitched calfskin strap with a titanium and white cold clasp.  The design reminds us a little of the Parmigiani Fleurier Bugatti Watch but a whole lot more complex; similarly, the $158,000 price tag is also impressive.

Press Release:

Horological Machine No4 Thunderbolt

A traditional wristwatch has a relatively straightforward role: to tell the time. All that is needed is a hand for the hours, another for the minutes and perhaps a power reserve indicator to keep track of running time. Horological Machine No4 Thunderbolt has a hand for the hours, another for the minutes and a power reserve indicator. HM4 Thunderbolt tells the time.

HM4 Thunderbolt is not a traditional wristwatch.

The aviation-inspired case and engine of the Thunderbolt 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.

The Thunderbolt's engine is the culmination of three long years of development. Each of the 300-plus components – including the regulator and even the screws – was developed specifically for this anarchistic calibre. Horizontally configured dual mainspring barrels drive two vertical gear trains, transferring power to the twin pods indicating hours/minutes and power reserve.

But describing HM4's engine through its mechanical functionality is like describing Renoir's work through the chemical composition of his paint. Only careful contemplation enables full appreciation, and the sapphire case section and display panels top and bottom allow full access to the flawless fine finishing of HM4's intricate and vibrant micro-mechanics.

The sleek aerodynamic form of the Thunderbolt's titanium and sapphire envelope has its roots in Maximilian Büsser's childhood passion for assembling model plane kits, though none looked remotely as futuristic as this. The striking transparent sapphire section of the case requires over 100 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 Thunderbolt's 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.

About MB&F

After decades learning and conforming to the corporate rules of watchmaking, Maximilian Büsser broke the chains and started a rebellion – a rebellion called MB&F. MB&F is an artistic and micro-engineering concept laboratory in which collectives of independent horological professionals are assembled each year to design and craft radical Horological Machines.

The ramifications of these audacious projects are profound. Respecting tradition but not shackled by it, MB&F fuses traditional, high-quality watchmaking with cutting-edge technology to create three-dimensional kinetic sculptures.

In the 19th century, photography liberated art from realism: Monet painted "Impressionism, Sunrise" giving rise to a new artistic movement based on re-interpreting light.

In the 21st century, electronics liberated watchmaking from timekeeping: MB&F created Horological Machines, giving rise to a new artistic movement based on re-interpreting horology.

Horological Machine No4 Thunderbolt

Inspiration and Realization: A long childhood passion for assembling model aircraft had Maximilian Büsser's walls, cupboards and ceiling covered in small aircraft of every description. Planes were what he saw last thing at night and planes were what he saw first thing each morning.

The boy became a man, but something of the child and his planes remained, quietly waiting until...HM4 Thunderbolt!

Many boys sketch supercars and fast planes, but few have the drive and determination to make their dreams come true. Büsser created MB&F to do just that. The HM4 Thunderbolt is born of the child's fantasy and the man's tenacity.

Engine: HM4's engine was entirely designed and developed by MB&F over three years of intensive work with Laurent Besse and Beranger Reynard of Les Artisans Horlogers. Each of the 311 components were developed specifically for the Thunderbolt, no off-the-shelf mechanisms or parts were used at all due to the extreme nature of its architecture.

Two mainspring barrels connected in parallel provide 72 hours of energy, and they transfer their power to the dual jet-turbine-like indication pods (one displaying the hours and minutes, the other the power reserve) via vertical gear trains.

Visible through a shaped sapphire display panel on the top of the case, a distinctive streamlined cock supports the balance, its centre cut away to reveal as much of the oscillating wheel as possible and validating the "kinetic" in MB&F's "kinetic art".

A work of art rewards when viewed from different angles and the Thunderbolt is no exception. Turning the machine over reveals a veritable panorama of meticulously finished micro-engineering through the sapphire sections. In a playful trompe d'oeil, what at first glance appears to be a micro-rotor in the form of MB&F's iconic battle-axe is actually a bridge.

Indications: For a timepiece not developed specifically to tell the time, HM4 performs that role superbly. In fact, with its highly legible dials perpendicular to the wearer's wrist, Horological Machine No4 might be described as the perfect pilot's or driver's watch.

On the left pod, the amount of fuel in the tanks – or power reserve – is clearly indicated by a skeletonised hand echoing MB&F's battle-axe motif. On the right, hours and minutes are displayed by bold, arrow-tipped Super-LumiNova filled hands. Each of the two aviation instrument-styled dials is directly controlled by its own crown, one to wind and re-fuel the tanks, the other to set the time, which provides direct and instantaneous feedback of the action performed.

Case: Inspired by aviation, more specifically the model aircraft kits of Maximilian Büsser's childhood, the case of HM4 imparts speed, power, technology and refinement in equal measure. Visually, the case is composed of three parts: two streamlined jet-turbine-styled pods supported by a horizontal section housing the engine, which is clearly visible through transparent sapphire display panels and the central section of the case itself.

Case (continued): Technically there are also three main sections, but these comprise a fore section in titanium, which includes the dials and articulated front lugs; a central section in sapphire offering unprecedented 360° access to the superbly finished engine; and an aft section tapering down to the dual crowns and framing the animated balance, which is supported by an aerodynamic cock. Methods borrowed from aeronautic engineering are visible in the externally mounted screws, which provide both rigidity and watch resistance to hold the case's three sections solidly and elegantly together.

Beginning with a solid piece of sapphire, more than 100 hours of intricate machining and meticulous polishing are required to turn an opaque block of crystal into the clear, light-filled atrium of the central case section, which reveals part of the Thunderbolt's engine and engineering details. The metal case sections are milled from solid blocks of high-tech Grade 5 titanium, which undergoes hundreds of hours of machining before polishing, masking and finally satin-finishing of the surfaces. The results speak for themselves.

The contrasts of matte with highly polished surfaces, titanium with sapphire, straight lines with seductive curves and rigid forms with articulated arms endows Horological Machine No4 with a life and vibrancy that sets it apart from anything that has ever gone before.

HM4 Thunderbolt is the quintessential machine as three-dimensional kinetic art.

Rupture in Art, Rupture in Watchmaking

Impressionist paintings scared classicists and were greatly misunderstood. MB&F's Horological Machines scare classicists and are greatly misunderstood. Horological Machine No4 is unlikely to change that, but the rupture with traditional watchmaking is so complete that it allows HM4 to be appreciated for what it is, i.e. raw, unfettered three-dimensional kinetic art.

Until the 19th century, art was fairly straightforward: painters did their best to replicate what they saw and their skill was judged on how closely they copied reality, with little latitude allowed for a brush-stroke or two of emotion. With the introduction of photography, even the greatest traditional artists could not compete in terms of realism. But that liberated more adventurous artists like Monet, Cézanne and Renoir to break from realism and to paint, not just with a brush-stroke or two of emotion but with raw, unfettered emotion.

In impressionist art, the fundamentals of the medium remain, i.e. paint on canvas, but the result was a rupture with the past. With MB&F's Horological Machines, again the fundamentals of the (horological) medium remain, i.e. intricate mechanical movements, and again the result is a rupture with the past.

Horological Machine No4 Thunderbolt – Technical Specifications


Three-dimensional horological engine developed 100% by MB&F

Manual winding with two mainspring barrels in parallel

Power reserve: 72 hours

Balance frequency: 21,600bph/3Hz

Number of components: 311

Number of jewels: 50


Hours, minutes and power reserve indicator

Hours and minutes on right dial, power reserve indicator on left dial

Separate crowns for time setting and winding


Grade 5 titanium and sapphire

Dimensions: 54mm wide x 52mm long x 24mm high

Number of components: 65

Articulation of lugs: 3°

Sapphire crystals:

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

Strap & Buckle:

Black hand-stitched calfskin strap with titanium/white gold custom designed deployment buckle attached to articulated lugs

'Friends' responsible for Horological Machine No4 "Thunderbolt"

Concept: Maximilian Büsser/MB&F

Product Design: Eric Giroud – Eric Giroud Design Studio

Technical and Production Management: Serge Kriknoff/MB&F

Production logistics: David Lamy/MB&F

Movement Development: Laurent Besse, Béranger Reynard and Patrick Lété of Les Artisans


Movement manufacturing: Daniel Uhlmann/Azuréa Technologies, Nicolas Broquet/Broquet

Décolletage, Yann Ryser/Tital

Hand-finishing of movement components: Jacques-Adrien Rochat and Denis Garcia of

C-L Rochat

Movement assemblage: Didier Dumas and Georges Veisy/MB&F

Case and buckle construction and production: Jean-Pierre Kohler and Lionel Gavignet of Profusion

Martin Stettler of Stettler

Dominique Mainier and Bertrand Jeunet of G.F.Châtelain

Dials: François Bernhard and Denis Parel of Nateber

Hands: Pierre Chillier, Isabelle Chillier and Félix Celetta of Fiedler

Strap: Olivier Purnot/Camille Fournet

Presentation box: Olivier Berthon/Berthon & Co