The difference between Lathe Machine and Milling Machine:
Lathe Machine(Instrumental & CNC): Item clamped by the working jig spins/rotates, while the lathe tools stay still. Nomarlly it is used for fabricating circular process, i.e. external&internal hole/ thread...
Milling Machine: on the contrary to the Lathe Machine. The item stays still while the tools spins and rotates. It is used for producing on edge(straighe lines)