Rough nut = one and one-half diameter of bolt + 1/8.Rough head = one and one-half diameter of bolt + 1/8.
Finished nut = one and one-half diameter of bolt + 1/16.Finished head = one and one-half diameter of bolt + 1/16.
Rough nut = diameter of bolt.Rough head = one-half distance between parallel sides of head.
Finished nut = diameter of bolt — 1/16.Finished head = diameter of bolt — 1/16.
2. (Hydraulics.) The first screw may have been the water-screw of Archimedes, about 236 B. C.
The Egyptians have an easy way to water the land by means of a certain engine invented by Archimedes, the Syracusan, which, from its form, is called cochlea. — Diodorus Siculus (60 B. C.).
It is believed that Archimedes designed the wheel to be moved by the current of the Nile, and it is certainly capable of being moved by a current of sufficient speed, or one deflected by wing dams to act upon the floats of the wheel.
Extending through the inclined shaft is a spiral passage, w<