Greubel Forsey Quadruple Tourbillon Secret

The Quadruple Tourbillon Secret represents a special link between Robert Greubel, Stephen Forsey and the collector. The ultimate refinement, this timepiece evokes to the passionate enthusiast the promise of an exceptional movement in which a magical mechanical ballet plays out on a hidden stage visible only through the display back. The dial side redefines the expression of telling the time with its harmonious arrangement of multiple dials.

Ultra-exclusive, the Quadruple Tourbillon Secret comes in a unique edition of eight pieces in 5N red gold and eight pieces in platinum.

The ultimate in refinement, the ballet of the tourbillons is visible only through the synthetic sapphire crystal display back. This private micro-mechanical performance becomes a witness to the bond that unites the owner with the values of Greubel Forsey. A bond further strengthened by the precious exclusivity of the Quadruple Tourbillon Secret.

This timepiece houses Greubel Forsey’s second fundamental invention, the Quadruple Tourbillon: a reliable high-performance mechanism comprising four tourbillons configured in independent pairs, which are linked by a spherical differential that averages out any timing errors between the two regulators. Particularly in stable positions, timekeeping accuracy is improved by the Quadruple Tourbillon.

The movement comprises 519 components of which 261 make up the four tourbillon cages and is powered by two mainspring barrels which provide an effective power reserve of 50 hours. The oscillators feature variable inertia balance wheels, Phillips terminal curves and beat at 3Hz/21,600 APH.

The plates and bridges are in nickel silver finished in nickel-palladium with straight-grained and spotted finishes and hand polished bevels. The dials are in blackened or silvered gold with applied indices.

The case is available in platinum 950 or 5N red gold and measures 43.5 mm in diameter by 16.11 mm high and features asymmetrical domed synthetic sapphire crystals on the dial side and for the display back. The black alligator strap is hand stitched with a folding clasp in platinum 950 or 5N red gold to complement the case.

Technical details

Model: Quadruple Tourbillon Secret
Unique edition of 8 pieces in platinum

Movement

Mechanical hand-wound movement, Calibre GF03j
Quadruple Tourbillon • power-reserve indicator• hour and minute display • small second • 4-minute outer tourbillon rotation indicators.
Movement with patented tourbillon

Movement dimensions
• Diameter: 36.40 mm
• Thickness: 9.85 mm

Number of parts
• Complete movement: 519 parts
• 4 tourbillon cages: 261 parts
• Total weight: 2.35 g
• Spherical differential: 28 parts

Number of jewels
• 63
• Olived-domed jewels in gold chatons

Power reserve
50 hours

Barrels
Rapid rotating twin barrels (1 turn in 3.2 hours) one of which is equipped with a slipping spring to avoid excess tension

Balance wheel
Free sprung variable-inertia balance with white gold mean-time screws (10.70 mm diameter)

Frequency
21’600 vibrations/hour

Balance spring
• Phillips terminal curve
• Geneva-style stud

Main Plates
Nickel silver, spotted with polished bevelling, straight-grained flanks, nickel palladium-finish

Bridges
• Nickel silver, frosted, spotted with polished bevelling, nickel-palladium finish
• Gold nameplate engraved with the individual number
• Two steel Tourbillon bridges (movement side): hand-bevelled, flat black polished with polished countersinks
• Two nickel silver Tourbillon bridges (dial side)

Gearing
• Involute circle profile
• Conical gearing with corrected profiles

Inner Tourbillons
Inclined at a 30° angle, 1 rotation per minute

Outer Tourbillons
• 1 rotation in 4 minutes
• Hand-bevelled and open-worked cage pillars
• 1 gold counterweight per double cage

Displays
• Hour and minute
• Small second (mean performance)
• 50-hour power reserve on a sector
• 4-minute outer-tourbillon rotation indicators

Exterior

Case
• In platinum 950 with asymmetrical convex sapphire crystal
• Transparent back with asymmetrical convex sapphire crystal
• Lateral window with shaped sapphire crystal
• Three-dimensional, variable geometry-shaped lugs
• Gold security screws
• Polished bezel and centre band with hand-finished straight graining
• Hand-engraved individual number
• Raised polished engraving “Quadruple Tourbillon” on a hand-punched background
• Unique edition of 8 pieces in platinum
Thickness: 16.11 mm
Water resistance of the case: 3 atm – 30 m – 100 ft (standard NIHS 92-20/SN ISO 22810:2010)
Crown: In platinum with engraved and black lacquered GF logo

Dial
• Silvered dial
• Gold hour markers
• Gold display sectors
• Applied gold GF logo

Hands
Hour and minute and small second in black steel
4-minute and power-reserve in polished gold

Strap and clasp
• Hand-sewn black alligator
• Platinum 950 folding clasp, hand-engraved with the Greubel Forsey logo

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