Les Cabinotiers Temporis Duo Grand Complication Insights

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To bring together in a wristwatch a minute repeater, a split-seconds chronograph and a tourbillon regulator is a technical challenge that has rarely been met. In the Les Cabinotiers Temporis Duo Grand Complication Openface these complications benefit from Vacheron Constantin‘s latest technical developments and continuous research into materials. Particular attention has also been paid to the decoration and hand-finishing of Calibre 2757 S, which comprises almost 700 components. This work is revealed through the complex sapphire dial as well as the sapphire back of the 45mm 5N pink gold (750/1000) case. This highly technical timepiece turns mechanical watchmaking into a kinetic art form that measures time.

Vacheron Constantin Les Cabinotiers Temporis Duo Grand Complication Openface

The evolution of age-old know-how

The complications of this new Les Cabinotiers timepiece epitomise the transmission of watchmaking expertise through the generations – a core value of Vacheron Constantin. In 1819, the Maison produced a pocket watch with independent deadbeat seconds and a quarter repeater, one of the first of its kind. The watch incorporated a deadbeat seconds mechanism – a device that had been developed by various watchmakers in the late 18th century as a means of more accurately measuring very small units of time. Designed as an independent mechanism with its own gear train, it enabled the seconds hand to be stopped and restarted independently of the normal timekeeping function and is thus considered to be the forerunner of the chronograph.

The split-seconds chronograph mechanism has two coaxial hands, the second of which can be stopped to calculate an intermediate time before being restarted to catch up with the first. After the system was introduced – first with a single-hand system in 1831, then with the two-hand configuration in 1838 – Vacheron Constantin quickly incorporated these developments into its pocket chronographs.

The Maison’s chiming watches draw on an equally deep history. Minute repeaters – watches that strike the hours, quarters and minutes on demand – have been part of Vacheron Constantin’s watchmaking vocabulary for more than two centuries. The first mention of a Vacheron Constantin striking timepiece in the production records is a gold quarter-repeating pocket watch recorded in 1806.

Since then, the Maison has continued to build its expertise in striking and repeating watches. Created in 1827, the first Vacheron Constantin watch with grande and petite sonneries, is an impressive example of this savoir-faire, as are Reference 4261 dating from the early 1940s, which incorporates a minute repeater in a calibre just 3.28 mm thick, and Reference 57260 which counts a grande et petite sonnerie (the former with Westminster chimes), a minute repeater, and an alarm among its 57 complications.

A similar historic evolution applies to the tourbillon. This mechanism, which significantly enhances isochronism by mitigating the effects of gravity, is first mentioned in the Maison‘s archives with an order placed in 1901 by a Parisian client for a highly complicated timepiece that was to incorporate such a regulator. Over the decades, Vacheron Constantin’s watchmakers have continued to develop the tourbillon, notably by developing technical solutions with multiple axes. The Les Cabinotiers Tourbillon Armillaire bi-axial wristwatch with a spherical hairspring and the Les Cabinotiers – The Berkley Grand Complication, featuring a triple-axis tourbillon, are outstanding examples of this expertise.

While the combination of a chronograph and a minute repeater in a movement with a tourbillon regulator has been seen in some remarkable pocket watches, it has remained rare in wristwatches. Vacheron Constantin saw this as an opportunity to create such a piece, in the tradition of the grand complication watches that have made its reputation for 270 years.

Three of Haute Horlogerie’s most emblematic complications, the chronograph, minute repeater and tourbillon are among the most difficult to create, let alone combine. Meeting the challenge, in 2022 the Maison unveiled Calibre 2757 in a single-piece edition Les Cabinotiers watch offering this rare and original combination in a single mechanism.

For the Les Cabinotiers Temporis Duo Grand Complication Openface, , the watchmakers of Les Cabinotiers developed a new version of the calibre, with a spherical hairspring to further improve isochronism, and set it in a one-of-a-kind watch that reveals the beauty and complexity of the movement through an open-worked dial.

Horological mastery

The highly technical Calibre 2757 S incorporates 696 components, with the design of the movement, particularly in terms of its chronograph functions, subject to the imperative of performance. Despite its complexity, the watchmakers at Vacheron Constantin have created a movement of great finesse, barely 10.4 mm high and 33.3 mm in diameter, remaining faithful to the principles of elegance that are a signature of the Maison.

When developing the original Calibre 2757, the additional split-seconds chronograph plate was specially designed with an in-depth arrangement of its components to enhance operating efficiency. This optimisation of volumes to ensure the calibre’s thinness, was complemented by the use of new materials. Some of the wheels in the gear train have been made of titanium or electroformed in nickel-phosphorus, with a toothing profile particular to Vacheron Constantin that ensures improved penetration of the gears to prevent the second hands from shaking.

After much research, the chronograph seconds hands were made of aluminium, chosen for its rigid and ultra-light properties. Silicon, another ultra-light material that requires no lubrication, was used for one of the split-seconds levers and its insulator. These savings in component weight and friction reduce the loss of energy amplitude from the barrel. This contributes to a comfortable power reserve of 50 hours with the chronograph engaged, indicated by a display on the back of the watch.

With measurements accurate to 1/5th of a second thanks to the movement’s frequency of 18,000 vibrations per hour, elapsed time is indicated on the peripheral minute track by the two central second hands, together with a 30-minute counter positioned at 2 o’clock. Because this function demands extremely high precision, Vacheron Constantin‘s watchmakers opted for a construction with two column-wheels, one devoted to the chronograph and the other to the split-seconds hand.

The chronograph is controlled by a single push-piece at 2 o’clock for the basic functions (start/stop/reset) and by a push-piece at 4 o’clock for the split-seconds (stop/reset). Pressing the latter stops the second hand at an intermediate time while the first hand continues its course. When pressed again, the split-seconds hand instantly joins the first hand in the time countdown.

A centripetal regulator and spherical hairspring

The minute repeater featured in Calibre 2757 S has also benefited from technical developments at Vacheron Constantin. These include an ingenious flying strike governor. This device has two weights shaped so as to act as a brake on the governor’s rotating shaft, thus evening-out the energy released by the repeater’s spring. To achieve this, it uses opposing centrifugal and centripetal forces. When the governor spins, the centrifugal force pivots one end of the weights outwards so that the other end acts as a brake on the central shaft to bring the rotation and the strike to a steady rate.

The governor mechanism, which operates in total silence, regulates both the cadence and duration of the musical sequence so that the notes can be heard distinctly and clearly, with a complete absence of mechanical ‘background noise’. The distinctive feature of this system is its two flyweights with a shape specially designed to generate a kind of ‘motor brake’ by a centripetal force acting on the governor’s rotating shaft. This evens out the energy released by the minute repeater barrel.

Located at 6 o’clock, the tourbillon is fitted with a spherical hairspring, a shape that causes the spring to expand and contract concentrically, thus enhancing isochronism. The distinctive tourbillon cage is inspired by the Maltese cross, the Maison’s emblem. Held in place by a hand-bevelled bridge. the tourbillon performs one complete rotation per minute and a hand mounted on its axis indicates the small seconds.

Technical excellence enhanced by Haute Horlogerie finishes

A transparent sapphire dial is the aesthetic signature of the new Les Cabinotiers Temporis Duo Grand Complication Openface. Just 0.5 mm thick, it is distinguished by a highly complex mix of finishes: polished and frosted surfaces alternate on the counters, which are encircled by rings in 5N gold, applied by metallisation on the underside of the sapphire discs; the hour markers are treated with grey NAC and the chronograph markers are engraved and inked. The 30-minute chronograph counter hand and the two chronograph seconds hands are made of PVD-coated aluminium – their olive green colour matched by the green alligator leather strap that attaches the 45mm pink gold case to the wrist.

The sapphire dial and caseback reveal the quality of the hand-finishing on the movement components, highlighting the beauty of this kinetic artwork. Surfaces are, variously, bevelled, polished, satin-finished, grained, circular-grained, engraved and bead-blasted, creating a fascinating play of reflections and light.

Visible through the dial, the sides of the skeletonised bridges are hand-drawn and hand-bevelled and the surfaces are circled. The wheels, with their bevelled spokes, are rolled and polished, a delicate operation that requires special tools when wheels are made of titanium. The metallic colours of the moving parts contrasts with the black NAC coating on the bridges and main plate.

On the reverse side of the movement, the watchmaker has created a distinctive decoration. The surface of the blackened bridges was hollowed out then sandblasted by hand to a very fine grain and edged with a mirror-polished sink. The hand-chamfered sinks for the jewels and screws have also been mirror-polished. The beauty of the movement architecture is amplified by the contrast between the black bridges, their polished borders and the golden tones of the moving parts. The striking governor is engraved with the initials JMV, in homage to Jean-Marc Vacheron, and held by a semi-circular bridge that has been round-polished by hand – the polishing alone requiring eight hours of meticulous work.

Thanks to the meticulous attention to detail dedicated to this calibre, it took twice as long for the finishing of its components as it did to assemble and fit it into the case. As was the case for the 18th-century cabinotiers, a single watchmaker was in charge of the watch, carrying out all of the component finishing, as well as every assembly operation, right down to the adjustment and casing of the calibre. This manner of working is an eloquent testimony to Vacheron Constantin’s commitment to safeguarding the transmission of watchmaking expertise through the generations.