The crown wheelCrown Wheel The crown wheel is a gear that interacts with the crown. When the crown is turned, the crown wheel rotates and winds the mainspring. [Learn More] is a gear that interacts with the crownCrown The knob on the outside of the watch that you typically use to either wind the mainspring or set the time [Learn More]. When the crown is turned, the crown wheel rotates and winds the mainspringMainspring The mainspring is a spiral-shaped metal spring that stores energy in a mechanical watch movement. It is located inside the barrel. The mainspring is wound, either manually or automatically. The mainspring unwinds over time, and the watch will stop running when the mainspring is fully unwound. [Learn More].