What do the terms “mechanical”, “self-winding” and “automatic” mean when they apply to a watch?
A “mechanical” watch is a timepiece that derives its power from a tightly coiled main spring housed in a drum or barrel inside the watchcase. As this spring unwinds, it releases the energy to power the gear train escapement, balance wheel and other parts of the mechanical movement. The term “self-winding” is really a misnomer. This is because a mechanical watch cannot wind itself; it must be worn, wound by hand or placed on a watch winder in order to operate continuously. An “automatic” watch is a mechanical timepiece that is wound as a result of the wearer’s wrist or body movements. Through the slightest motion a rotor inside the watchcase will rotate or oscillate and wind the mainspring.
