Screw (simple machine) of the last of the simple machines to be invented. It first appeared in ancient Greece and Egypt, and by the first century BC was used in the form of the screw press and the Archimedes' screw, but when it was invented is unknown. Greek philosopher Archytas of Tarrentum (428 – 347 BC) was said by the Greeks to have invented the screw. Although the Greek philosopher Archimedes is credited by the Greeks with inventing the Archimedes screw water pump around 234 BC. records indicate it was first used in ancient Egypt. Archimedes was first to study the screw as
Screw So, as a general rule, when buying a packet of "screws" nuts would not be expected to be included, but bolts are often sold with matching nuts. Part of the confusion over this is likely due to regional or dialectical differences. "Machinery's Handbook" describes the distinction as follows: This distinction is consistent with ASME B18.2.1 and some dictionary definitions for "screw" and "bolt". The issue of what is a screw and what is a bolt is not completely resolved with "Machinery's Handbook" distinction, however, because of confounding terms, the ambiguous nature of some parts of the distinction, and usage variations.