Over the last decade, two indelible forms have often marked MB&F’s Horological Machines: the distinctive angular form and optical prism displays of the revisited 1970s Amida watch, which first manifested in HM5 and then HMX; and the now signature “battle-axe” winding rotor, which took centre stage on top of HM3, MB&F’s most popular model to date.

Horological Machine N°8 (HM8) takes those two idiosyncratic features and infuses them with high-octane Can-Am race car-inspired design – generating an exquisitely sculptured, high-speed wrist-borne fantasy.

An idea was born

When he was young, MB&F founder Maximilian Büsser dreamt of becoming a car designer, but that wasn’t an option and he ended up designing watches instead. Or did he? It wouldn’t take much to scale HM8 up to car size, drop a 1,000+ horsepower motor under the sapphire crystal hood and put a set of slick racing tyres under the chassis.

While visually it is those polished roll bars linking HM8 to the Can-Am supercars, it’s the rebellious spirit of working outside restrictive rules that really provided the inspiration for HM8.

Case, roll bars, and crystals

At first glance it may appear that the sapphire crystal covering the HM8 Engine is circular and positioned above the battle-axe rotor, but it’s not. The complete top of the case is one piece of sapphire crystal with sections of the crystal metallised to create a bluish border. That crystal, combined with the polished roll bars on each side, the oil sumps underneath, and the time displays created by optical prisms highlight HM8’s unrestricted horological creativity.

The roll bars are in grade 5 titanium, which has the desired qualities of being light in weight and high in strength. But that strength comes with a twist: titanium is not very malleable and cannot be bent easily into the desired long curve, which means that each roll bar has to be milled from a solid block of titanium Ti-6Al-4V. This is a blend of pure titanium with 6% aluminium and 4% vanadium as well as trace amounts of iron and oxygen. The Ti-6Al-4V alloy is significantly stronger than commercially pure titanium and boasts an excellent combination of lightness, strength, and resistance to corrosion.

Turning HM8 over reveals another automotive tip of the hat: like most car engines which have an “oil sump” located underneath, HM8 has dual oil sumps under its own Engine.

Movement

HM8 Can-Am is powered by an in-house developed bi-directional jumping hour and trailing minute indication module, on a Girard-Perregaux base movement. The movement is inverted to put the winding rotor on top and modified to drive the prism indicator module. The finishing of the movement is first class, which it has to be as it is completely open to view from the top. The power reserve is 42 hours.

Indications and reflective prisms

The bi-directional jumping hour and trailing minute displays on HM8 are materialised by overlapping discs (one for the hours, one for the minutes), completely covered in Super-LumiNova. The effect of large numerals is created by masking all of the lume except for the numbers.

The discs rotate horizontally on top of the movement; they are visible in the corners of the transparent Engine cover. Yet the time indications are displayed vertically in a ‘dashboard’ at the front of the case. To achieve this, MB&F worked with a high-precision optical glass supplier to develop reflective sapphire crystal prisms that reflect light from the discs 90°. The prisms also magnify the indications by 20% to maximise legibility.

HM8 has separate sapphire crystal prisms for the hour and minute displays, which are wedge-shaped with precisely calculated angles to ensure that light is reflected (and reversed) from the horizontal indications to the vertical rather than refracted (bent). A convex lens at the front provides the magnification.

Sapphire crystal is much more difficult to work to optical precision than glass, and it took considerable development and meticulous care in production to create crystals that reflected and magnified light without the slightest distortion. Because the time is reflected, the numbers are printed on the discs as mirror images so that they display correctly on the ‘dial’.

The vertical, forward-facing display makes HM8 Can-Am an excellent driver’s watch, as there is no need to lift your wrist from the steering wheel to read the display.

Movement

Three-dimensional engine conceived and developed by MB&F from a Girard-Perregaux base calibre
Automatic battle-axe winding rotor in 22k gold
Power reserve: 42 hours
Balance frequency: 28,800bph / 4Hz
Number of components: 247
Number of jewels: 30
Functions/indications

Bi-directional jumping hours and trailing minutes displayed by two optical prisms that both reflect and magnify
Case

Material: launch editions in 18k white gold/titanium and 18k red gold/titanium
Dimensions: 49 mm x 51.5 mm x 19 mm
Number of components: 60 components
Water resistance: 30 m / 90′ / 3 atm
Sapphire crystals

All sapphire crystals – front, back, top, bottom – treated with anti-reflective coating on both faces
Strap & buckle

Hand-stitched alligator strap in marine blue (white gold case) and dark brown (red gold case) with folding buckle in matching case material