Screw-cutting lathe name "screw-cutting lathe" carries a taxonomic qualification on its use—it is a term of historical classification rather than one of current commercial machine tool terminology. Early lathes, many centuries ago, were not adapted to screw-cutting. Later, from the Late Middle Ages until the early nineteenth century, some lathes were distinguishable as "screw-cutting lathes" because of the screw-cutting ability specially built into them. Since then, most metalworking lathes have this ability built in, but they are not called "screw-cutting lathes" in modern taxonomy. The screw has been known for millennia. Archimedes devised the water screw, a system for raising water. Screws
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.