The purpose of a lathe is to rotate a part against a tool whose position it controls. The spindle is the part of the lathe that rotates. Various workholding attachments such as three jaw chucks, collets, and centers can be held in the spindle.
Spindle speed is contolled by varying the geometry of the drive train.
The tailstock can be used to support the end of the workpiece with a center, or to hold tools for drilling, reaming, threading, or cutting tapers. It can be adjusted in position along the ways to accomodate different length workpices. The ram can be fed along the axis of rotation with the tailstock handwheel. The carriage controls and supports the cutting tool. An apron that controls the feed mechanisms.