The machinist needs machinery and therefore uses an engine lathe, milling machine, grinder, or any other machine in a battery of machine tools, as metal cutting tools are called. If the individual can use all of these machines, as well as the hand tools, read blueprints, handle shop mathematics, heat-treated steel and use measuring instruments to work to fine tolerances, the person is called a machinist. The principle work of a machinist is to operate machine tools. Accuracy is very important in metal machining work. Some metal parts are machined to within 10 millionths of an inch.
Blueprints specify the dimensions of finished parts.
Micrometers and other precision measuring instruments to check work accuracy are used. Skilled machinists also lay out and assemble metal parts. They use chisel scrapers, files, and other small hand tools in chipping, filing, and polishing the parts so that they fit together exactly. The largest number of machining workers are skilled and semi-skilled workers who run lathes, drilling machines, milling machines, grinders and other machine tools. Machine tool operators commonly work with only one kind of machine tool.