The Main Parts of a Metal Lathe

Metal lathe is used for precise machining of metals, plastics and other hard materials. This machine tool removes symmetrical features on metals and other hard materials on a rotating spindle with the use of cutting tools such as drill bits and tool bits. The ability to design on metals and other materials will depend on the machinist’s skill and operational understanding of the main parts of a metal lathe.

The metal lathe is divided into four major components: the bed, the carriage, the tailstock and the head stock. Each of these major components includes different subparts with distinctive purpose for machining. To learn the basic orientation of these machine parts will guide a promising machinist to the intricacies of using the metal lathe in fabricating customized work pieces.

The bed of the metal lathe serves as the foundation of the lathe assembly. It supports the carriage, the headstock and the tailstock in a symmetrical housing. During machining operations, the tailstock and carriage slide on a finely machined surface or railings known as “ways.” Different metal lathes have beds with gaps near the headstock to provide more rooms for large diameters of materials to turn. There are also gaps with pieces of bed that one can bolt and remove. In large lathes, a sliding bed, where the carriage and tailstock assembled, can be slid along a lower separate section of the lathe giving a larger or smaller gap for the turned material.

The carriage holds and supports the saddle, apron, cross slide, compound rest (top slide) and tool post. The saddle is the casting found on the top of the bed and slides along the bed. This moves both longitudinally (turning) or perpendicularly (facing) along the bed and under the control of the machinist. The apron carries different gears and controls for the carriage that can be power driven along the bed. Also found in the carriage are T-slots or tapped holes used for clamping in boring and milling operations. The carriage is always in the released (free) position and moved by hand until such time that the automatic power feed is applied.

The tailstock is used to hold the work piece dead centered during the machining operations. It has a clamping nut to secure the work in place and in the desired position. It moves along the ways on the bed to accommodate different lengths of work. The tailstock is also used to clamp tools for threading, cutting, drilling or reaming. The work piece can be secured with a spindle along the axis of rotation using the tailstock hand wheel. The spindle is moved along the tailstock barrel for longitudinal tuning. The tailstock is divided into two sections: the bottom or base is attached to the ways and the top can be moved laterally on its base. Setscrews can be adjusted for lateral movement. On both base and top, zero marks are inscribed to indicate center position and measurement for taper turning.

The headstock holds the main head spindle, speed mechanism and the driving gear mechanism to turn it during operation. The driving mechanism is connected to a cone pulley that drives the spindle and also attached to back gears that controls its speed. The work piece turns slowly when the spindle is driven through the back gears. The headstock can be turned in different speeds.