Heavy Duty Shaft Face Lathe Machine Cutting Process .... "The selection of a cutting tool is probably the most important decision a machinist can make. We are going to cover some of the basics, but I urge everyone who intends to use the lathe, to learn as much about cutting tools as possible. Turning on the lathe is one of the most common metalcutting operations. Lathes are particularly suited to machining relatively long, cylindrical workpieces, yet can create a variety of parts ranging from small watch components to massive propeller shafts.