TECHNICAL SPECIFICATIONS OF THE CALIBER RICHARD MILLE RM 052 TOURBILLON SKULL Limited edition of 21 pieces, which includes 15 pieces in titanium and 6 unique set pieces in red or white gold. CALIBER RM052: manual winding tourbillon movement with hours, minutes. Dimensions: 42.70 mm x 50.00 mm x 15.95 mm. MAIN FEATURES POWER RESERVE Circa 48 hours. BASEPLATE AND BRIDGES IN GRADE 5 TITANIUM The RM 052 revolves around the skull. This is fascinating from an artistic point of view, but even more so from a technical point of view. The baseplate has been finished in grade 5 titanium, a biocompatible, highly corrosion-resistant and remarkably rigid alloy, which enables the gear train to function effortlessly. The alloy is 90% titanium, 6% aluminium and 4% vanadium. This combination further increases its mechanical properties, which explains its frequent use in the aerospace, aeronautical and automobile industries. The upper and lower jaws holds the tourbillon cage jewel. The rear of the skull acts as a central bridge. The “Jolly Roger” comes to life thanks to the 4 bridges that link the movement to the case. The skeletonized baseplate and the bridges have been subjected to intensive and complete validation tests to optimize their resistance capacities. BALANCE WHEEL WITH VARIABLE INERTIA The free-sprung balance provides better reliability in the event of shocks, movement assembly and disassembly. It also guarantees better chronometric results over an extended period of time. There is no need for an index plate, allowing more precise and frequent adjustment using 4 setting screws. FAST ROTATING BARREL (6 hours per revolution instead of 7.5 hours) This type of barrel provides the following advantages: - The phenomenon of periodic internal mainspring adhesion is significantly diminished, thereby increasing performance, - Provision of an excellent mainspring delta curve with an ideal power reserve/performance and regularity ratio. BARREL PAWL WITH PROGRESSIVE RECOIL This device permits a profitable winding gain (circa 20 %), especially during the winding start. It is also helpful in the distribution of the mainspring’s internal tension. 1 RM 052 TOURBILLON SKULL WINDING BARREL TEETH AND THIRD-WHEEL PINION WITH CENTRAL INVOLUTE PROFILE The central involute profile of the winding barrel teeth and pinion provides an optimal pressure angle of 20°. This promotes effective rotary motion and allows for compensation of possible variations in the engagement of the going train thus insuring excellent torque transmission with a distinct improvement in performance. SPLINE SCREWS IN GRADE 5 TITANIUM FOR THE BRIDGES This permits better control of the torque applied to the screws during assembly. These screws are therefore unaffected by physical manipulation during assembly or disassembly and age well. OTHER FEATURES - Movement dimensions: 32.80 x 30.90 mm - Thickness: 6.87 mm - Tourbillon diameter: 10.90 mm - Balance wheel diameter: 9.12 mm - Number of jewels: 19 - Balance wheel: GLUCYDUR, 2 arms, 4 setting screws - Moment of inertia: 11.50 mg.cm2, angle of lift 53° - Frequency: 21,600 vph (3 Hz) - Balance spring: in ELINVAR by NIVAROX - Shock protection: KIF ELASTOR KE 160 B28 - Barrel shaft in nickel-free Chronifer (DIN x 46 Cr13 + S), with with following characteristics: stainless, antimagnetic, tempered. CASE The case of the RM 052 requires 86 stamping operations, of which 49 make up the striking of the three principal components (bezel, case middle and case back), before the cutting and milling can start. A first for Richard Mille, the case has been lightened by creating openings in the bezel and the case back. This skeletonised, original case reinforces the visual identity of the RM 052 Skull. It takes 20 hours to set a machine and 30 hours of programming to produce just a single kit. The case requires 255 machining operations and the finishing phase involves 5 hours of satin finishing and polishing. A five-axis machining centre (perfected machine) must be used to create the case's complex form. For each case machined, a period of 45 minutes is needed just for the positive engraving of the name “Richard Mille”. The chamfered edges of the case pillars and the openings to the bezel and the case back are hand-polished. The tripartite case is water resistant to 50 meters, ensured by two Nitril O-ring seals. The case is assembled with 20 Spline screws in grade 5 titanium and abrasion resistant washers in 316L stainless steel. SPLINE SCREWS IN GRADE 5 TITANIUM FOR THE CASE This permits better control of the torque applied to the screws during assembly. These screws are therefore unaffected by physical manipulation during assembly or disassembly and age well. 2 RM 052 TOURBILLON SKULL TORQUE LIMITING CROWN This additional security system prevents from accidental overwinding, which could cause damage to the winding stem or putting extreme pressure on the mainspring barrel. FLANGES Upper flange in carbon, lower flange in grade 5 titanium with DLC coating. CRYSTAL Bezel side: in sapphire (1,800 Vickers) with anti-glare coating (on both sides). Thickness: 1.50 mm Case back: in sapphire with anti-glare coating (on both sides) Thickness: 1.20 mm in the centre and 2.04 mm at the outer edges FINISHING MOVEMENT - Hand-polished bevelling - Microblasted milled sections - Drawn or polished outer faces STEEL PARTS - Microblasted surfaces - Satin-brushed surfaces - Hand-polished bevelling - Hand-drawn finishing on the upper surfaces - Matt strokes on the underside - Lengthwise hand-drawn strokes on the sides - Polished sinks PROFILE-TURNING - Lapped and polished ends - Burnished pivots WHEELS - Concave chamfering with a diamond tool - Circular-smoothed faces - Rhodium plating (before cutting the teeth). Minimal corrections are made to the wheels to preserve their geometry and overall performance. 3.