Machine tools were rare in 1750. Grooving a file, cutting a gear tooth, rounding and polishing were essentially manual gestures. The maker of this machine benefited from experiments by 18th-century master watchmakers. In their search for precision, they designed tools capable of accurately making watch parts. A few turns of a crank was all it took to evenly groove the metal's surface by means of a cam that controlled the hammer striking the chisel. The grooves' depth varied depending on the type of file desired. The tension of the flat spring above the hammer determined the movement's intensity, and therefore the depth of the imprint the chisel left on the hot metal. This mechanical marvel foreshadowed the industrial machine age, when manual gestures were mechanised. But the dainty elegance of its scrolls and the perfection of its steel skeleton bear witness to a time when mechanics was an art.