Double Tourbillon 30° Technique
In Ceramic – A Timepiece Unveiled
In Ceramic – A Timepiece Unveiled
Inspired by the phenomena of transparency and light, Robert Greubel and Stephen Forsey are pushing back the boundaries of horological architecture to draw the beholder deep inside an emblematic Greubel Forsey timepiece. For the first time encased in ceramic – a highly rigid material – this limited edition of 11 timepieces is made available to the US market.
The shades of the impressively finished and detailed blue ceramic case play with the light flooding through into the sapphire crystal movement. The timepiece has been reconstructed to incorporate these elements, requiring a very particular expertise and know-how. It now reveals the captivating spectacle of the two completely suspended cages of the Double Tourbillon 30° mechanism.
Click , to see the large size. ▶ BIG FOTO
Click , to see the large size. ▶ BIG FOTO
This proved a success for the independent Atelier, and seven years later, the Double Tourbillon 30° Technique won first prize at the Concours International de Chronométrie. The timepiece achieved a record score of 915 points out of 1000 with an average timing rate of between 0.3 and 0.8 seconds per day across the whole competition. Now Greubel Forsey is presenting the Double Tourbillon 30° Technique in ceramic, an extraordinarily accurate timepiece that is both refined and robust.
Unparalleled accuracy
The Double Tourbillon 30° at the heart of the timepiece contributes to its exceptional accuracy. Inside a cage which rotates in four minutes, a smaller cage containing the balance and spring assembly is inclined at an angle of 30° relative to the first cage and completes a revolution in 60 seconds. The combination of the 30° inclination with the different rotational speeds of the two tourbillons improves timekeeping by averaging out positional errors due to gravity in all usual wristwatch positions and especially in stable positions.
Click , to see the large size. ▶ BIG FOTO
Immersive architecture
Transparency has always been an integral part of Greubel Forsey creations, and this proves particularly evident in the construction of the various editions of the Double Tourbillon 30° Technique – all presenting a panoptic view of the movement’s architecture. This Double Tourbillon 30° Technique in ceramic pushes back the boundaries of transparency even further by revisiting the construction of the entire timepiece to work with the specific constraints of sapphire crystal. The eye can distinguish each element in marvellous detail. The small seconds and power- reserve indicators in gold are finished in blue to present a contrasting effect against the frosted main plates and recall the glistening blue ceramic. The hour and minute ring, as well as the 4-minute tourbillon-rotation indicator at 6 o’clock are both made from sapphire to let the light into all levels of the mechanism. The hands are openworked to further enhance the sense of light and transparency. Seemingly suspended in mid-air in a mystical dance, the Double Tourbillon 30° immediately attracts the attention of the viewer.
Sapphire and exceptional know-how
Having reconstructed the movement, Robert Greubel and Stephen Forsey embraced the challenge of accommodating sapphire crystal elements, particularly complex to machine in three dimensions and to finish to achieve the unique geometry and exacting standards of a Greubel Forsey timepiece. The two creator watchmakers took the movement to the architectural extreme, creating three-dimensional sapphire bridges that proved particularly challenging to realise. Machined from single blocks of sapphire, their flanks are polished using different grains, requiring highly specialised tools, exceptional precision and expertise. The bevelled angles reveal a matt finish that magnificently contrasts with the polished transparent surfaces of the sapphire. Thanks to this transparency, the entirety of the wheels and pinions comprising the timepiece are laid bare to reveal unprecedented visual access to the movement architecture.
Click , to see the large size. ▶ BIG FOTO
Click , to see the large size. ▶ BIG FOTO
The ceramic case: robustness and radiance
This is the first time that Greubel Forsey showcases a movement inside a ceramic case, the making of which requires great precision. The material is compacted by pressing and shaped before firing, where a thermal process shrinks it by around 25%. Ultimately, the case measures 48.40 mm in diameter and 17.77 mm in height. Once the elements have been sintered at a very high temperature, the ceramic solidifies, making the case extremely hard and therefore more difficult to work with. The material becomes extremely resistant to scratches and corrosion, meaning the finishing requires exceptional know-how. From polishing to linear or circular satin- finishing, the finishes refine the contours of the timepiece, perfecting it in the true Greubel Forsey spirit. The deep blue ceramic gives the Double Tourbillon 30° Technique a subtle shimmer, while its physical properties make it extremely resistant. Myriad colours, finishes and textures play across the blue ceramic case and the sapphire movement.
Click , to see the large size. ▶ BIG FOTO
Double Tourbillon 30° in ceramic: a robust and radiant timepiece with its movement unveiled.
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TECHNICAL SPECIFICATIONS
Collection: Double Tourbillon 30°
Limited edition of 11 ceramic pieces
Hand-wound movement with synthetic sapphire bridges
Patented tourbillon
Double Tourbillon 30° • hours and minutes • small seconds •
outer tourbillon 4-minutes rotation • inner tourbillon 60-seconds • power-reserve
Movement
Movement dimensions
• Diameter : 38.40 mm
• Thickness : 12.15 mm
Number of parts
• Movement : 421 parts
• Two tourbillon cages : 132 parts
• Weight of the two cages : 1.17 g
Number of jewels • 43
• Olived-domed jewels in gold chatons
Chronometric power reserve • 120 hours
Barrels
• 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
• 22k gold cover with nickel-palladium treatment and relief engraving
Balance wheel
• Variable-inertia 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, frosted with polished bevelling and countersinks, straight-grained flanks,
nickel-palladium treatment
Bridges
• Synthetic sapphire crystal, polished flanks
• Nickel silver, frosted and spotted with polished
bevelling and countersinks, straight-grained flanks, nickel-palladium treatment
• Gold plate engraved with the individual number Inner tourbillon
• Inclined at a 30° angle, 1 rotation per minute Outer tourbillon
• 1 rotation in 4 minutes
• Hand-bevelled and openworked cage pillars
• Gold counterweight
Gearing
• Involute circle profile
• Conical gearing with profiled teeth
Displays
• Hours and minutes
• Small seconds
• 120-hours power reserve on a sector
• 4-minutes outer tourbillon rotation
• 60-seconds inner tourbillon rotation
Exterior
Case
• Ceramic
• Caseback, bezel and caseband machined from a block of ceramic, polished and straight grained, hand-finished
• Three-dimensional, variable geometry-shaped lugs
• Engraving “Double Tourbillon 30°” and “Greubel Forsey"
• Engraved individual number
Case dimensions
• Diameter : 48.40 mm
• Height : 17.77 mm
Water resistance of the case
• Water-resistant 3 atm - 30 m - 100 ft (standard NIHS 92-20/SN ISO 22810:2010)
Crown
• Ceramic with engraved GF logo
Dial side
• Multi-level synthetic sapphire hour-ring, galvanic growth hour indexes,
engraved and lacquered inner tourbillon rotation indicator
• Small seconds and power-reserve indicators in gold, blue finish
Hands
• Hours and minutes in polished gold, with Super-LumiNova
• Small seconds, power-reserve (red triangles)
• Engraved synthetic sapphire 4-minutes indicator
Strap and clasp
• Rubber
• Titanium folding clasp, engraved with the GF logo
Unique edition
Limited Edition of 66 pieces.
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Press Release - 2019
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GREUBEL FORSEY SA
For further information:
Communication Department
press@greubelforsey.com – +41 79 194 2884
Eplatures-Grise -16 P.O. Box 670
2301 La Chaux-de-Fonds - Switzerland
+41 32 925-4545
+41 32 925-4502
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