This clockmaker's lathe is operated by means of a pulley. The transmission belts are missing. The clamp mechanism can be set to the desired position and holds various types of cutters for precision-milling of teeth of different profiles and sizes. The dividing plate underneath, with adjustable rod, is used to determine the number and exact position of the teeth along the rim of the fixed disk. On the plate are engraved concentric circles of points whose number is equal to the number of teeth of the most commonly used gearwheels. The dividing plate, as a simple calculating instrument, was probably invented toward the mid-fifteenth century, perhaps by Giovanni Torriano of Cremona. The machine that uses it in combination with a lathe and high-speed precision tooth-cutter was invented in England shortly after the mid-seventeenth century and was perfected by Robert Hooke c. 1672.