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
Trammel of Archimedes in the form of the standard parametric equations for an ellipse in canonical position. The further equation is immediate as well. The trammel of Archimedes is an example of a four-bar linkage with two sliders and two pivots, and is special case of the more general oblique trammel. The axes constraining the pivots do not have to be perpendicular and the points "A", "B" and "C" can form a triangle. The resulting locus of "C" is still an ellipse. Trammel of Archimedes A trammel of Archimedes is a mechanism that generates the shape of an ellipse. It consists of two