Richard Mille Tourbillon RM 052 Skeleton
We're all familiar with skeleton watches, but this Richard Mille Tourbillon is more accurately described as a skeleton watch, hence the name: Tourbillon RM 052 Skull. Debuted at SIHH in 2012, the watch is limited to 21 pieces, 15 in titanium and six in exclusive rose or white gold.
Of course, the watch's signature feature is its striking skull-shaped baseplate, made of grade 5 titanium. Not only is it a clever design element, however, it is also incorporated into the movement: the upper and lower 'claws' grip the rubies of the tourbillon cage, while the back of the skull is also the movement's central bridge. The four bridges that connect the movement to the case are arranged in a "skull and crossbones" pattern inspired by the flag of a pirate ship. The soleplate and bridges (hollowed out, naturally) have been rigorously tested to ensure high strength and rigidity. The titanium alloys used for them are also frequently used in the aerospace, automotive and aviation industries due to their high corrosion resistance.
Other technical aspects include a free-spring balance wheel, which provides shock protection and allows for more precise adjustment; a fast-turning barrel (6 hours per revolution instead of 7.5 hours), which helps improve performance by reducing the cohesion of the mainspring; belt Barrel pawls with progressive recoil help distribute the internal tension of the mainspring; and spline screws are made of grade 5 titanium for the bridges for better torque control during assembly. A tripartite case requires 255 machining steps, including 86 stamping operations. Richard Mille made the large case lighter by opening holes in the bezel and case back. The case also uses titanium spline screws for greater torque control and has a torque-limiting crown, an extra safety feature that prevents accidental overwinding.