RM 031
CREATING THE WORLD’S MOST ACCURATE WRISTWATCH
While our technical-aesthetic credo is to open up fine watchmaking to the worlds of art, sport and lifestyle, our purpose here was to tackle the archetype of watchmaking as a fine art, with performance as an added bonus. This model proved our capacity to produce a quintessential specimen of watchmaking orthodoxy which guarantees extreme performance over the long term.
The RM 031 is a timepiece that combines watchmaking tradition with pioneering concepts. Despite its orthodox design, it is the result of a determined desire to create the world’s most consistent mechanical calibre.
This is a highly ambitious goal that demands a variation of less than 30 seconds per month from the RM 031, which is far more difficult to obtain than more traditional daily accuracy rates allowing a variation in accuracy of 5 to 8 seconds per day.
RM 031 Manual Winding High Performance Chronometer
CALIBRE RM031
Manual winding movement with hours, minutes, small seconds, and function indicator.
Limited edition of 10 pieces
POWER RESERVE
Circa 50 hours (± 10%).
BASEPLATE AND GEAR-TRAIN BRIDGES IN ARCAP®
The Richard Mille brand is fully committed to the pursuit of performance. This approach has led the RM engineers to use materials with extraordinary physical properties sourced from sectors far-removed from watchmaking, such as aviation, the automotive industry and cutting-edge electronics.
Used for the first time on the RM 002, ARCAP® is a material renowned for its physical characteristics. With its antimagnetic properties and a density of just 8.90 g/cm3, its is almost completely insensitive to large temperature variations and invulnerable to corrosion. These qualities explain why ARCAP® is frequently used in the aeronautics, automotive and advanced electronics industries.
Another of ARCAP®’s ideal characteristics for fine watchmaking is its propensity to accept extreme finishing with inimitable results.
BARREL AND BALANCE BRIDGES IN GRADE 5 TITANIUM
These components are made from grade 5 titanium, treated with a black PVD coating, which gives the whole structure great rigidity and excellent surface flatness, both essential for the perfect functioning of the gear train.
DIRECT IMPULSE AP ESCAPEMENT
Subtle combination of a detent escapement and a Swiss anchor escapement, the direct impulse escapment allows the achievement of exceptional timing regulation and chronometric results.
Beating at 36,000 vph and linked to a double barrel, the regularity with which this high beat escapement functions is a key organ in the race for the ultimate results in performance.
OPTIMAL GEAR TEETH PROFILE
To fully utilise the regularity of the RM 031, the perfect transmission of energy to, and through, the going train is an absolute necessity. As such, the Richard Mille movement engineers have focused on the watch’s transmission by giving the teeth of the entire gear train a pressure angle of 20°. This pressure angle favours rolling and better withstands inter-axial differences.
FUNCTION INDICATOR
In a manner similar to a car’s gearbox, the function indicator allows one to see the winding, neutral and hand-setting positions as the crown is pulled out.
ARGON-PROTECTED MOVEMENT
For optimal results, the RM031 High Performance calibre operates in a neutral environment of Argon gas. The gas is injected into the case by means of a capsule screwed into the platinum caseband at 9 o’clock. Argon is a noble gas and thus chemically inert. In addition, it provides excellent thermal insulation, allowing the movement to work as if in a vacuum. This improves chronometric accuracy as there are no external influences to affect performance. Argon also protects the wheels and their oils from degradation, thereby playing a major role in the calibre’s superlative chronometric results.
MOVEMENT CHARACTERISTICS
Movement diameter: 36.00 mm
Thickness: 6.35 mm
Number of jewels: 26, set in white gold chatons
Balance wheel: CuBe, 4 arms, 4 regulating screws, moment of inertia 10 mg•cm2, angle of lift 50°
Frequency: 36,000 vph (5 Hz)
Balance spring: opposed elinvar double balance spring
Escapement: AP direct-impulse anchor
Shock protection: INCABLOC 908.22.211.100 (transparent)
CASE
The design and execution of the watch demonstrate a holistic approach to conception of the movement, case and dial. As a result, everything has been constructed according to extremely rigorous specifications, in the manner of the analytical engineering methods used in the design of Formula 1 racing cars, where the chassis and the engine are developed in complete harmony.
The casing ring is eliminated, and the movement is fixed to the chassis by three grade 5 titanium screws and silicon blocks (ISO SW).
The case is composed of four parts and is assembled using 12 spline screws in grade 5 titanium and washers in 316L stainless steel. The system is completed by the incorporation of the lugs as separate elements of the case design and is water-resistant to 50 metres.
EXTREME FINISHING
The RM 031 High Performance Chronometer displays a quality of finish rarely found even in Haute Horlogerie. The finish adorning every component of the movement and case is created by hand.
The baseplate and escapement bridge are made of microblasted ARCAP®. The large baseplate has raised and polished edge details, combined with black rhodium-plated areas, while the upper surfaces of the escapement bridge are straight-grained.
The grade 5 titanium barrel bridges are microblasted by hand and finished with anglage.
The various bridges that make up the RM 031 are straight-grained with hand-finished anglage. The wheels are polished, microblasted, bevelled and circular-grained.
The sections are burnished and the escapement bridges are soft-polished. A PVD treatment is also applied to the parts in grade 5 titanium.
Finishing
Movement
• Hand-polished bevelling
• Microblasted milled sections
• Hand-polished sinks
• Hand-polished rear surface
• Burnished surface on the dial side
Steel parts
• Satin-finished upper surfaces
• Hand-polished bevelling
• Hand-polished sinks
• Burnished sections
Wheels
• Concave chamfering with a diamond tool
• Hand-polished angles
• Circular-finished faces
• Microblasted milled section
• Rhodium plating (before cutting the teeth)
Other features
DOUBLE-BARREL SYSTEM
The double-barrel system helps to improve torque stability over a longer period. This is achieved by distributing the stored energy across two winding barrels instead of one, which increases the number of rotations and reduces pressure on the teeth, bearings and pivots, resulting in better long-term performance.
FAST-ROTATING BARREL (4 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.
SPLINE SCREWS IN GRADE 5 TITANIUM FOR THE BRIDGES AND CASE
This permits better control of the torque applied to screws during assembly. These screws are therefore unaffected by physical manipulation during assembly or disassembly and age well.