STOPWORK

Stopwork is a simple mechanism designed to limit the winding of the mainspring. It consists of a wheel fixed to the barrel arbor. This wheel features a finger that meshes with a Maltese cross, one of whose notches is blind. As the watch is wound, the finger drives the Maltese cross until it reaches the blind slot, which stops the winding mechanism in advance. This prevents the mainspring from being over-tensioned at the end of winding and reduces the risk of breakage.

Once widespread, such mechanisms are now rare. Modern slipping bridle systems and improved mainspring materials have largely eliminated the need for traditional stopwork.

Useful links:

– The barrel
– The winding mechanism