Greubel Forsey Différentiel d'Égalité Limted Edition of 33 Pieces 18k White Gold

$ 295,000.00 USD

Spherical Différentiel d’Égalité • inclined fixed escapement • hours and minutes • dead-beat seconds • small seconds • power-reserve • stop balance and reset on dead-beat seconds Robert Greubel and Stephen Forsey first unveiled their invention at Baselworld 2008 as part of the EWT Laboratory and then presented a more advanced version of a technical demonstrator at SIHH 2010. Since then, further exciting paths have been explored to help optimise accuracy in this new timepiece. The Différentiel d’Égalité enables steady distribution of power from the mainspring barrel to the regulating organ, which maintains a constant balance amplitude during the 60 hours of the power reserve. In a first for Robert Greubel and Stephen Forsey, this timepiece features dead-beat seconds. This makes it easier to read and to set the time precisely. The timepiece is equipped with a balance wheel stop and seconds reset activated by pulling the crown. The heart and the hammer of this mechanism are visible on the movement side. The 30° angle of the balance wheel and escapement minimises the effects of gravity and ensures efficient movement performance in stable positions. This Greubel Forsey technique guarantees excellent mean/averaged balance wheel performance, which is the mark of heightened timekeeping accuracy. All of these components work together magnificently to help improve performance.

Movement
Movement dimensions
Diameter : 36.40 mm
Tickness : 9.99 mm
Number of parts
Movement : 359 parts
Escapement platform : 71 parts
Number of jewels 47 Olived-domed jewels in gold chatons
Barrels Two series-coupled fast rotating barrels (1 turn in 3.2 hours), one of which is equipped with a slipping spring to avoid excess tension
Barrel with relief engraving "Greubel Forsey"
Balance wheel Variable-inertia with gold mean-time screws (10 mm diameter)
Frequency 21'600 vibrations/hour
Balance spring Phillips terminal curve Geneva-style stud
Main plates Nickel silver, frosted and spotted, with polished bevelling and countersinks, straight-grained flanks, nickel-palladium treatment
Bridges Circular-grained gold plate with individual number, polished bevelling and countersinks, straight- grained flanks
Gearing Involute circle profile
Spherical Différentiel d’Égalité with conical gearing
Conical profiled teeth for inclined fixed escapement
Displays
Hours and minutes
Dead-beat seconds
Small seconds
60-hours power reserve on a sector
Spherical Différentiel d’Égalité
24 parts including 4 jewels and 3 satellites
Differential cage, circular-grained, polished bevelling and countersinks, straight-grained flanks
Uniform torque, rewinding once per second with integrated spring
Chronometric power reserve
60 hours ± 10%
Optimized amplitude over the entire power reserve
Stopwork mechanism
Reset mechanism
Stop balance and reset activated by crown
Flat black polished steel reset mechanism, polished bevelling, straight-grained flanks Case
In white gold with high domed synthetic sapphire crystal
Transparent back with synthetic sapphire crystal
Three-dimensional, variable geometry-shaped lugs
Raised polished engraving “Différentiel d’Égalité” and “Greubel Forsey” on a hand-punched background
Gold security screws
Hand-polished bezel, caseband with hand-finished straight graining
Hand-engraved individual number
Case dimensions
Diameter : 44.00 mm
Height : 15.30 mm
Water resistance of case
Water-resistant 3 atm - 30 m - 100 ft (Standard NIHS 92-20/SN ISO 22810:2010)
Crown In white gold with engraved and black lacquered GF logo
Dial Multi-level synthetic sapphire hour-ring, lacquered galvanic growth hour indexes, engraved and lacquered minutes and dead-beat seconds
Small second and power-reserve indicators in gold, engraved and black lacquered, hand matt lapped
Hands Hours and minutes in polished gold, with Super-LumiNova
Small seconds, dead-beat seconds and power-reserve in polished blued steel, hand-polished countersinks
Strap and clasp Hand-sewn alligator
White gold folding clasp, hand-engraved with the GF logo