The caliber 3500 inside the Grande Complication is one of four new calibers Vacheron introduces this year at SIHH. This thin, self-winding movement measures 33.4 mm in diameter by just 5.2 mm in thickness. A total of 459 components comprise the movement, some of which are exceedingly tiny (and we mean tiny – there are springs within that measure 3/100ths of a millimeter).

The movement features 51-hours of power reserve, supported by a peripheral oscillating weight moving around the perimeter of the movement, allowing an almost unobstructed view of the hand-finished components through a sapphire-crystal case back. The rotor itself is hand-engraved with a pattern inspired by scroll-work on the balance cock of Vacheron’s oldest pocket watch, ca. 1755.

From a technical standpoint, the movement showcases multiple advancements in component design and engineering. To minimize unwanted jerking of the chronograph seconds hands, the clutch system was designed with a “friction” technique, allowing the user to operate the function more fluidly. The peripheral oscillating rotor stops itself when fully-wound, preventing overwinding of (and thus excessive tension on) the winding spring. Additionally, micro-technologies have been used to cut the teeth of the cone-shaped wheels to specifically maximize surface contact, improving overall efficiency in the gear train.