The Pursuit of Wearing Thin

A conventional crown that accommodates a case as thin as a nickel would be impossible to handle, hence the crown takes a rectangular form and is seamlessly recessed into the case band. This preserves the symmetry of the case while protecting the crown from impacts. But an inevitable downside is that it is still not big enough to be operated with bare fingers, thus requiring a motorized tool for both winding and setting. More impressive are the modifications in the keyless works, which conventionally are made up of a winding stem, clutch, winding and sliding pinion which collectively take up both vertical and horizontal space. Piaget’s ingenious solution is a worm screw, which it dubs the “infinite screw”. Its spiral threads enable it to engage and drive a gear laterally on the same plane, significantly reducing the footprint.

Additionally, the barrel has an open design revealing its state of wind in a “hanging” construction. However, it is supported on its periphery by ceramic ball bearings in addition to being supported on its bottom pivot. In the same vein, the balance assembly – its hairspring, staff, cock, shock absorber jewel cap – which determines the height of every movement, had to be rethought. For the first time in a watch, the balance is not secured in place by a bridge or a cock. Instead, the shaft of the balance is supported on ball bearings integrated in the main plate. This reduces the height of the movement while eliminating the need for shock absorbers. And as a result of removing the balance cock, the hairspring had to be attached to a circular bridge screwed to the main plate, hence is located under the balance wheel. Consequently, with such a design, the balance had to be free-sprung.