Gear and speed changing mechanism together with the main spindle are housed here. An electric motor drives the spindle though back in the early days, lathes were driven by the use of a flat belt pulley. More often than not the end of the main spindle has a Morse taper.
This is a base that is connected to the headstock. The connection ensures that the spindle access moves in parallel with the tailstock and carriage. The tailstock and carriage are restrained in a set rack by the bedways so as to facilitate movement.
Feedscrews are long driveshafts connecting to a series of gears that are on the apron so as to allow the carriage to drive along the Z-axis. The function of the leadscrew is the same only that it operates orthogonally to the feedscrew hence causing movement of the carriage along the X-axis.
It is composed of the top/saddle and apron/the side. It moves the cutting tool perpendicularly for facing operations and longitudinally for turning operations.
This is the center mount that is positioned on the opposite side of the headstock. The spindle that is found in the tailstock does not rotate. From the function of a leadscrew, it moves longitudinally.