Alongside the 32 day power reserve ID Two Concept Watch, Cartier also announced the Astrotourbillon Carbon Crystal. This is the first instance of commercialisation of the technology in the regulation and lubrication free ID One of 2009. The Astrotourbillon Carbon Crystal combines the Astrotourbillon complication with the carbon crystal escapement of the ID One. As some of you might know, the Astrotourbillon is a central carousel tourbillon. That is because A) the balance wheel is not co-axial with the axis of rotation of the carriage and the fourth wheel, making it a carousel; and B) it is a central tourbillon because the tourbillon carriage and fourth wheels of the Astrotourbillon movement are co-axial with the axis of the hour and minute hands and the centre of the movement. The original Astrotourbillon in white gold For those who know the work of Carole Forestier, Cartier’s head of technical development, the Astrotourbillon in keeping with her past innovations (Piaget Tourbillon Relatif, Panerai tourbillon and the concept of the UN Freak). Given the unique characteristics of this tourbillon, it was chosen as the timepiece into which the technology of the ID One is first used on a commercial scale. The Astrotourbillon Carbon Crystal has the tourbillon bridges, escape wheel and pallet fork in carbon crystal (which is actually artificial diamond). These carbon crystal components are made by Deep Reactive-Ion Etching (DRIE), which produces parts with tolerance of one micron – exceptionally precise by watchmaking standards. So the geometry and precision of the escape wheel and anchor are perfect. Each and every tooth of the escape wheel is shaped as it should be for optimal performance, not always the case with a steel escape wheel (which is why painstaking hand finishing is required). The same goes for the anchor; no ruby pallets held by shellac are needed, eliminating the potential for error in alignment. Just as importantly the parts are extremely hard and smooth; carbon crystal has a Vickers hardness of 10,000 (sapphire is about 2300). Consequently the contact surfaces of the escape wheel and pallet fork have a friction coefficient of 0.04 (against 0.15 for normal steel parts). As a result, the escapement requires no lubrication. Instead of jewelled bearings the tourbillon cage has apertures precisely formed during the manufacturing process. Because they are formed with DRIE, they are perfectly formed in diameter and shape, unlikely conventional jewels which are pressed and may be ill formed or misaligned. The only jewels in the tourbillon are those for the balance staff (which along with the balance wheel and hairspring are conventional alloy). And the pivots are all tungsten carbide inside ADLC coated steel tubes, which again need no lubrication. The Astrotourbillon was chosen as the first carbon crystal model also because the tourbillon bridge is extremely large. Because carbon crystal is very light, it significantly reduces the weight of the tourbillon itself, by 20% compared to the titanium cage of the original Astrotourbillon. Along with the escape wheel and pallet fork in carbon crystal, the resulting weight reduction means that the movement functions more efficiently, with less torque needed. Like in the ID One, the carbon crystal tourbillon bridge of the Astrotourbillon is mounted on silent blocks for shock resistance. And carbon crystal is amagnetic, so the Astrotourbillon Carbon Crystal is not affected by magnetic fields. Originally in white or rose gold, this special Astrotourbillon is in a lightweight niobium titanium alloy case and limited to 50 pieces. The case is the classic Rotonde de Cartier shape, though the dial has a hint of modernity with its alternating Roman and baton indices, as well as the white on grey colour scheme, and of course the open centre which reveals the workings of the tourbillon bridge. The Astrotourbillon Carbon Crystal is the exciting first step in a journey towards the future of watchmaking as Cartier sees it. This is only the first step in the gradual implementation of ideas from the ID One; of the important bits only the escapement wheel and pallet fork are carbon crystal, the balance remains traditional. But this still raises plenty of questions – what happens to finishing or the regleur? But Cartier has demonstrated its capability for bold thinking and even more importantly the ability to put it into serial production. - SJX