Using different turning tools or other cutting tools on a lathe, various rotary surfaces can be machined, such as inner and outer cylindrical surfaces, inner and outer conical surfaces, threads, grooves, end faces, and forming surfaces. The machining accuracy can reach IT{{0}}IT7, and the surface roughness Ra value is 1.6-0.8. Turning is often used to machine parts with a single axis, such as straight shafts and general disc and sleeve parts. If the installation position of the workpiece is changed or the lathe is appropriately modified, multi axis parts (such as crankshafts, eccentric wheels, etc.) or disc camshafts can also be machined. In single piece small batch production, various types of parts such as shafts, discs, and sleeves are mostly processed using horizontal lathes or CNC lathes with wide adaptability; Large parts with large diameter and short length (length to diameter ratio 0.3-0.8) are often processed using vertical lathes. When producing small and medium-sized shafts and sleeve parts with complex shapes and inner holes and threads in batches, a turret lathe should be used for processing. When producing small parts with less complex shapes in large quantities, such as screws, nuts, pipe joints, shaft sleeves, etc., semi-automatic and automatic lathes are often used for processing. It has high productivity but low accuracy.