Fusee (horology)
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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
A fusee in a 1760 pocket watch by Johan Lindquist of Stockholm
A clock with the back plate off showing the fusee
Stackfreed
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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
Fusee (horology)
…inaccurate timekeeping. This problem is called lack of isochronism. Two solutions to this problem appeared with the first spring driven clocks; the stackfreed and the fusee. The stackfreed, a crude cam compensator, added a lot of friction and was abandoned after less than a century. The fusee was a much more…
Stackfreed in a watch