Just a few months after the last world record for the ultra-thin mechanical watch, the Bulgari Octo Finissimo Ultra with a thickness of 1.8 mm, comes a new record. It has been won by Richard Mille, which beats the competition with the first model born of its partnership with Ferrari. The new ultra-thin watchmaking limit becomes 1.75 mm: the total thickness of the RM UP-01 Ferrari, with a movement just 1.18 mm thick. But the dimensions are not exactly small: 41.45 x 28.85 mm.
Unlike Bulgari and Piaget (a previous first), which fused the case and movements together, Richard Mille has managed to maintain a traditional architecture by assembling the entire calibre between bridges and a traditional mainplate (as opposed to a construction in which the caseback also functions as a mainplate). Most of the components of the manual calibre, made in collaboration with Audemars Piguet Le Locle, with hours, minutes and crown function selector and resistant to accelerations of more than 5,000 g, are distributed over a very large surface area and not superimposed. For optimal operation of the gear train, the skeleton plate and bridges are made of grade 5 titanium, which guarantees perfect flatness without compromising robustness.
Part of this development also involved the design of a new patented ultra-flat escapement with a free-sprung balance and variable inertia in titanium. In order to reduce the thickness, the safety disc and dart, the two parts that 'control' the movement of the anchor during the free movement phase of the balance, were eliminated and replaced with a fork extension and new horns.
The watch's broad design allows it to remain so flat, extending over a rounded rectangular case measuring 51 mm x 39 mm in titanium, with water resistance to 10 metres. The two sapphire crystals, one placed on the time display (in the centre of the upper half of the case), the other positioned above the balance wheel to show the workings of the movement, are a mere two-tenths of a millimetre thick, with a diameter calculated to guarantee resistance during testing. The iconic laser-engraved Prancing Horse of Ferrari is not missing.
In a space-saving solution, it was also necessary to rethink the winding and reset mechanism and eliminate the winding shaft. As a result, the two crowns (one for selecting the winding or reset function, the other for using the selected function) are integrated horizontally into the thickness of the case.
It is a veritable exercise in watchmaking engineering in a volume bordering on the impossible, in the stylistic language of Richard Mille, made in only 150 examples. The result of dozens of prototypes and over 6,000 hours of development and laboratory tests.
