Fly Pinion—The pinion in a clock that carries the fly: a part of the striking mechanism.
Fob—Properly a watch pocket in the waistband of trousers. Commonly applied to the end of a chain or ribbon which is attached to the watch and hangs free from the pocket. One of the early examples was attached to a watch made for Oliver Cromwell in 1625 by John Midwall in Fleet Street.
Foliot—A straight armed balance with weights used as one of the earliest clock regulators. De Vick's clock is one example of it.
Foliot Balance—See Foliot.
Follower—Of two wheels geared together, the one to which the driver imparts motion is called the follower.
Fork—The fork shaped end of the lever into which plays the roller jewel.