GREUBEL FORSEY Double Tourbillon 30° Secret White Gold Limited Edition

When introducing their Double Tourbillon 30° at BaselWorld 2004, inventor-watchmakers Robert Greubel and Stephen Forsey defined an architectural approach focusing on the visibility of their invention, so as to ensure complete visual access to the double cage and its incredible mechanical choreography.

Dedicated to connoisseurs of haute horlogerie with a preference for discretion and for whom observing the mechanism is an intensely personal pleasure, the Double Tourbillon 30° now appears in a less extrovert and one might almost say ‘secretive’ style, even though such a splendid dial naturally hints at the treasure it is guarding.

This exquisitely crafted, matt-finished gold dial suggests the presence of an exceptional mechanism thanks to its unusual and particularly wide subdial at 6 o’clock with a slender blued steel hand testifying to the four-minute rotation of the Double Tourbillon 30°’s outer cage. The power-reserve is displayed on a sector indicating the full 72 hours of perfect operation provided by rapid-rotating twin barrels.

Issued in a strictly limited edition of 11, the Double Tourbillon 30° “Secret ” comes in a white gold case that is entirely polished, apart from the centre band of the case which is delicately straight-grained by hand.Fortunately however, the secret of this Double Tourbillon 30° is not impenetrable. Although hidden from view on the wrist, the choreographic performance of the cages can be admired through a caseback protected by a domed sapphire crystal.

The 128 parts making up the first fundamental Greubel- Forsey invention weigh a total of 1.17 grams, enabling the variable -inertia balance to oscillate to and fro three times a second, whereas its rotation axis shifts constantly due to the relative speeds of the cages and the 30° angle that links them together.

Technical details

Movement
Mechanical hand-wound movement, Calibre GF 02j
Diameter: 36.4 mm
Thickness: 9.65 mm

Number of parts
– Complete movement: 304 parts
– Tourbillon cage: 128 parts
Weight of the cage: 1.17 g
Number of jewels: 39; Olive-domed jewels in gold chatons

Power reserve: 72 hours
Barrels: Rapid rotating twin barrels(1 Turn in 3.2 hours)one of which equipped with a slipping spring so as to avoid excess tension
Balance wheel: Free sprung balance with white gold mean-time screws (10mm diameter)
Frequency: 21’600 vibrations/hour
Balance spring: Phillips terminal curve; Geneva-style stud
Main Plates: In nickel silver with fine circular graining centred around the Tourbillon, finished in “jade gold”
Bridges: Hand-Frosted nickel silver, finished in «jade gold»
Gearing: Involute circle profile; Conical gearing with corrected profile
Inner Tourbillon: Inclined at a 30° angle, 1 rotation per minute
Outer Tourbillon: 1 rotation in 4 minutes; Hand-bevelled and open-worked cage pillars; Solid gold counterweight

Displays
Hours and minutes
Small second
4-minute Outer Tourbillon rotation indicator
72-hour power reserve on a sector
Habillage

Case
Gold with convex sapphire crystal
Limited edition of 11 pieces
Transparent back with convex sapphire crystal
Raised engraving of the name of the invention on a hand-punched background
Gold security screws
Polished bezel, centre band with hand-finished straight graining
3 dimensional, variable geometry-shaped lugs
Hand engraved individual number
Case dimensions: Diameter: 43.5 mm & Thickness: 15.84 mm
Water resistance of the case: 3 atm – 30 m – 100 ft
Crown: Gold with engraved and black lacquered GF logo

Dial
Two-part gold dial
Silvered finish
Gold appliques
Gold small seconds and power reserve sectors
Gold Plate with individual number
Applied gold logo
Hands: Hours and minutes, small seconds, power-reserve and 4-minute indicator in flame-blued polished steel

Strap
Hand-sewn black or brown alligator leather with gold folding clasp, hand-embossed with the Greubel Forsey initials

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