Headstock: The headstock is the powered end and is always at the operator's left. This contains the speed changing gears and the revolving, driving spindle, to which any one of several types of work holders is attached. The center of the spindle is hollow so that long bars may be put through it for machining.
Tailstock: The tailstock is non-rotating but on hardened ways, it can be moved, to the left or right, to adjust to the length of the work. It can also be offset for cutting small-angle tapers.
Carriage: The carriage can be moved left or right either by hand wheel or power feed. This provides the motion along the Z axis. During this travel turning cuts are made.
Apron: The apron attached to the front of the carriage, holds most of the control levers. These include the levers that engage and reverse the feed lengthwise (Z axis) or crosswise (X axis), and the lever that engages the threading gears.
Cross Slide: The cross slide is mounted on the carriage and can be moved in and out (X axis) perpendicular to the carriage motion. This is the part that moves when facing cuts are made with power feed, or at any time a cut must be made "square" with the Z axis. This, or the compound, is also used to set the depth of cut when turning. The cross slide can be moved by its hand wheel or by power feed. .
Compound Rest: The compound rest, or compound for short, is mounted on the carriage. It can be moved in and out by its hand wheel for facing or for setting the depth of cut. It can also be rotated 360 degrees and fed by its hand wheel at any angle. The compound does not have any power feed but it always moves longitudinally with the cross slide and the carriage.
Tool Post: The tool post is mounted on the compound rest. This can be any of several varieties but in its simplest form is merely a slotted cylinder that can be moved left or right in the T-slot in the compound and clamped in place. It can also be rotated so as to present the cutter to the work at whatever angle is best for the job.
Bed: The bed of the lathe is its backbone. It must be rigid enough to resist deflection in any direction under load. The bed is made of cast iron or a steel weldment, in a box or I-beam shape, and is supported on legs, a cabinet or a bench.
Guideways: The ways of the lathe are the flat or V-shaped surfaces on which the carriage and the tailstock are moved left and right. Each has its separate pair of ways, often one flat surface, for stability, and one V-way for guidance in a perfectly straight line. These ways are hardened and scraped or ground to close tolerances. The basic accuracy of movement of the carriage depends on the ways.