The Double Tourbillon Technique Black breaks completely new ground for Greubel Forsey: It is the first black model in the Collection and the first Greubel Forsey timepiece to feature a titanium case and a rubber strap. These features endow this three‐dimensional chef d’oeuvre with more casual aesthetics than the classic gold and platinum models. Highly polished steel bridges stand out in high‐contrast juxtaposition against the subdued black chrome of the movement plates and bridges.
The Double Tourbillon Technique Black features a unique, open‐work movement architecture in an entirely original and innovative interpretation of Greubel Forsey’s first fundamental invention, the Double Tourbillon 30°.
The Double Tourbillon Technique Black is a case study in high‐precision mechanical watchmaking. The sapphire crystal is a portal through which to observe the mesmerising synchronised rotations of the intricate, sublimely finished, micro‐mechanics beneath. Gazing down through the multiple levels of the three‐dimensional movement, the viewer is naturally drawn from one component to the next. The open construction does not simply enable, but encourages and rewards careful observation of each separate element and their dynamic interactions.
At the heart of the Double Tourbillon Technique Black is the Double Tourbillon 30° mechanism at 6 o’clock, with the unobstructed configuration of the open movement allowing full appreciation of the ballet of the two tourbillons, one rotating inside the other.
Hours and minutes are displayed by luminous, open‐worked signature Greubel Forsey hands against a transparent sapphire crystal ring, providing full visual access and luminosity to the depths of the mechanisms below. Transparency is also manifest at 6 o’clock with a red‐tipped, four‐pointed, sapphire crystal indicator rotating in four minutes above the double tourbillon, and indicates 0‐60 seconds along a quadrant.
The three dimensionality of the Double Tourbillon Technique Black is apparent throughout. A visual journey across the top half of the movement takes us from the small seconds near 9 o’clock, past the four coaxial mainspring barrels and the tall jewel‐capped tripod supporting the hour and minute hands, to the power reserve indicator at 3 o’clock. Both the small seconds and power reserve indicators are balanced and strikingly enhanced by their red triangular indicators.
The four fast‐rotating co‐axial mainspring barrels provide a very generous 120 hours of autonomy. The rotation of the barrels can be enjoyed both when winding and when unwinding. Coupled to these barrels is the visible spherical differential that drives the power reserve indicator. Watch makers of Greubel Forsey are renowned for their uncompromisingly superlative finishing and decoration. The Double Tourbillon Technique Black is a kinetic showcase of this art with each and every component, visible or not, designed to highlight its form and hand finish. Plates and bridges have sharp internal angles to highlight the meticulous handcraft. Flat black‐polished steel bridges and mirror‐polished complex curves reflect light in a scintillating display, bringing unparalleled vivacity to the movement.
The raison d’être of the Double Tourbillon 30° Technique is its unique three‐dimensional, openwork movement architecture. Whereas a skeletonised movement takes an existing calibre and cuts away ‘superfluous’ material in only two dimensions, the movement of the Double Tourbillon 30° Technique was designed and developed from the ground up to allow unprecedented three dimensional visual access to as much of the mesmerising micro‐mechanics and mechanisms as possible. Sublimely finished components on all levels can be enjoyed from a multitude of angles thanks to the Double Tourbillon 30° Technique’s panoptic construction.
Double Tourbillon 30°
The Double Tourbillon 30° was Greubel Forsey’s first Fundamental Invention presented in 2004 and features an innovative Double Tourbillon 30° mechanism with one 60‐second tourbillon inclined at 30° rotating inside another tourbillon cage rotating in four minutes. In this world‐premier construction, the double tourbillons average out gravity‐induced errors on the balance and spring oscillator, which improves timekeeping. This construction allows for superior chronometric performance, a minimum volume/maximum balance diameter ratio as well as enabling the beautifully finished mechanism to be fully appreciated.
Black Titanium Case, Lugs, Crown and Clasp
The central hour and minute hands are skeletonised and filled with white Super‐LumiNova that stands out against the black‐chrome finished movement beneath. The triangular hands of the small seconds and power reserve indicator are hand‐finished in red anodised aluminium. The dial of the small seconds is one piece in gold (as is the power reserve dial) with a straight‐grained centre and lapped perimeter with engraved lacquer‐filled markers. A cut away sapphire disk around the perimeter of the display features metallised hour markers.
Three‐dimensional detachable lugs in titanium allow a fine finish of all surfaces of the case. The bespoke Greubel Forsey folding clasp in black titanium features a double folding mechanism with dual release pushers for additional security.
Fine Finishing and Aesthetics
As with all Greubel Forsey timepieces, the level of hand finishing and decoration throughout the Double Tourbillon 30° Technique is second to none. And the impeccable finishing goes much deeper than immaculate surface treatments as the components have been created with forms and shapes that highlight their beauty to maximum effect, offering myriad sublime details to be discovered and esteemed. Frosted plates, scintillating flat black‐mirror‐polished steel on flat and curved surfaces as well as the stunning bevels – many with sharp internal angles that machines cannot finish as well as a highly experienced hand – bring unparalleled vivacity. Large jewels set in polished gold chatons, and mirror‐polished and heat blued screws provide evidence of the extremely high quality that pervades every aspect of this timepiece.
Model: Double Tourbillon Technique Black (In ADLC black titanium)
Mechanical hand-wound movement with patented tourbillon
• Diameter: 38.40 mm
• Thickness: 12.15 mm
Number of parts
• Complete movement: 385 parts
• 2 tourbillon cages: 132 parts
• Weight of the two cages: 1.22 g
Number of jewels
• Olived-domed jewels in gold chatons
• 120 hours
• Four coaxial series-coupled fast-rotating barrels (1 turn in 3.2 hours), one of which is equipped with a slipping spring to avoid excess tension
• Black finished 22 k gold cover with relief engraving
• Free sprung variable-inertia balance with white gold mean-time screws (10.70 mm diameter)
• 21’600 vibrations/hour
• Phillips terminal curve
• Geneva-style stud
• Nickel silver, frosted with polished bevelling, black chrome treatment
• Nickel silver, frosted, spotted with polished bevelling, black chrome treatment
• Gold plate engraved with the individual number
• Inclined at a 30° angle, 1 rotation per minute
• 1 rotation in 4 minutes
• Hand-bevelled and openworked cage pillars
• Gold counterweight
• Involute circle profile
• Conical gearing with corrected profile
• Hour and minute
• Small second
• 120-hour power reserve on a sector
• 4-minute outer tourbillon rotation indicator
• In titanium with convex synthetic sapphire crystal
• Transparent back with synthetic sapphire crystal
• Raised polished engraving “Double Tourbillon 30° Technique” on a hand-punched background
• Three-dimensional, variable geometryshaped lugs, screwed fi xing
• Gold security screws
• 2 titanium engraved and hand-finished plates bearing text screwed to the caseband
• Hand-engraved individual number
• Water-resistant 3 atm – 30 m – 100 ft (standard NIHS 92-20/SN ISO 22810:2010)
• Crown: Titanium with engraved GF logo
• Diameter: 47.50 mm
• Thickness: 16.84 mm
• Synthetic sapphire crystal hour-dial
• Small second and power-reserve sectors in gold
• Hour and minute in polished gold with Super-LumiNova
• Small second, power reserve (red triangles)
• Synthetic sapphire crystal 4-minute engraved indicator
Strap and clasp
• Hand-sewn black rubber strap
• Titanium folding clasp, hand- engraved with the Greubel Forsey logo