Stackfreed
Videos
A stackfreed is a simple spring-loaded cam mechanism used in some of the earliest antique spring-driven clocks and watches to even out the force of the mainspring, to improve timekeeping accuracy. Sta
Stackfreed in a watch
Fusee (horology)
Videos
A fusee is a cone-shaped pulley with a helical groove around it, wound with a cord or chain attached to the mainspring barrel of antique mechanical watches and clocks. It was used from the 15th centur
Stackfreed
…accuracy. Stackfreeds were used in some German clocks and watches from the 16th to the 17th century, before they were replaced in later timepieces by the fusee. The term may have come from a compound of the German words starke ("strong") and feder ("spring"). Spring-driven clocks were invented around 1400 in…
A fusee in a 1760 pocket watch by Johan Lindquist of Stockholm
A clock with the back plate off showing the fusee