Triangular-bed lathes were common from the late 1700 through to the last quarter of the 19th century. Today they are rare, especially the Boley type illustrated here, a machine intended for clock rather than watch work. These lathes, built using a great deal of precision hand fitting, were remarkably accurate and capable of the finest work on early microscopes, telescopes, clocks and telegraphic and other mechanical instruments. Two versions of the lathe are shown on this page, the one towards the bottom being complete with its unusual combined hand and foot-powered countershaft unit. More triangular-bed Boley lathe pictures here
Another G.Boley watchmakers' lathe of a different (and unusual) design can be seen here.