Determine the time of machining (in min) a mild steel bar of 52 mm diameter to 44 mm diameter over a length of 200 mm with an approach length of 5 mm.

Use the following data:

Roughing cut is 3 mm deep with a cutting velocity of 35 m/min and feed of 0.3 mm/rev.

The finishing cut is 1 mm deep with a velocity of 50 m/min and feed 0.1 mm/rev.