A 50-mm-diameter bar is to be screw-threaded, for 250 mm of its length, on a lathe. The included angle of the thread is 60°, the pitch 2.5 mm, and the outside diameter of the threaded portion is to be 50 mm.
a) If the deformed chip thickness is limited to 0.13 mm, how many passes of the tool will be required to complete the operation?
b) If the rotational frequency of the workpiece is 0.8 S-1 s, what will be the total machining time?