DROP

In watchmaking, the Drop is a small circular protrusion, in the shape of a ring or raised plateau, formed at the bottom of a recess in order to reduce the contact surface — and therefore the friction — between two superimposed components. By bearing only on a narrow annular bearing surface rather than on the entire surface of the recess, parasitic friction is limited, wear is reduced, and the Lubricant deposited at this location, by capillarity, in the surrounding recess is retained more effectively. A Drop is frequently found in recesses made under the Bridge of the Barrel, at the location where the Ratchet wheel and the Crown wheel rest, components subjected to considerable stress during winding and operation of the winding mechanism. The Drop can also be found under other wheels or moving parts whenever a wide flat bearing surface would be detrimental to proper functioning. It thus fulfils a function that is both mechanical and tribological: it stabilizes the bearing, promotes even wear, and improves the retention of the lubricant film over time. A discreet construction detail, it reflects the care taken by manufacturers in managing friction, a constant concern in precision watchmaking.