Ordinary brass clock wheels will do for a clockwork gramophone or phonograph motor. The motive power can be the mainspring and main-wheel complete of an eight-day American clock, but a stronger wheel would wear better. The train consists of three wheels and pinions (see Figs. 1 and 2), and each wheel and pinion has a ratio of about 6 to 1. They are controlled by a weight governor like a steam-engine governor. The last wheel of the train carries the discs and drives the governor. The wheels are mounted on studs on a bedplate, as in Fig. 1. The last one, carrying the discs, has a long " pipe."

Fig. 1.

Clockwork Motor for Gramophone or Phonograph.