model, scale 1:2, segmental turning lathe

This is an early object for turning cylindrical portions of objects in which complete revolution was either unnecessary or impossible. Such tools have been used for machining crank arms or valve links. At the top of two tall standards , which are extensions ot the fast headstock of the lathe, is a speed cone and flywheel, driving by reducing gear, an overhanging crank arm of adjustable throw. A connecting rod from the crank works a rack sliding in a vertical guideand gearing onto a spur wheel secured to the headstock mandrel. As the crank rotates the work in the lathe is rotated to and frothrough an angle that is determined by the throw of the crank. The length of the connecting rod is also adjustable so that the portion of the work being operated upon can be quickly changed. The lathe bed has an internal traversing screw, and carries a slide rest, the tool holder, which is the winged type that is usually found in planing machines.