Special lathe, particularly for making settings exactly fitting the gem or the like

A lathe for making circular settings for stones or gems consisting of a frame, a rotating spindle having a vertically oriented rotating axis for carrying the workpiece in which the setting is to be made and a rotating turret proviced with a plurality of tool-carrying heads having tools carried therein, a flange provided with a cam and a plurality of one-way catches, disposed on said frame adapted to cooperate with said spindle and bring said tool-carrying heads into the vicinity of the vertical axis thereof when said turret is rotated and shape a setting in said workpiece carried by said spindle, a guage vice located on said frame for holding a stone or gem for which the setting is to be made and which gauge vice includes a piston element provided with an inclined plane at one end and a brake element near the opposite end acting thereon to clamp said piston in place when said stone or gem diameter has been detected by said guage vice, the inclined plane of said piston element contacting said one-way catches on said cam and adjusting the angular positioning of a tool in a tool-carrying head in the vicinity of the vertical axis of said spindle.