Almost every product made by American industry contains metal parts or is manufactured by machines made of metal parts. Many of these parts are cut to precise dimensions by machining workers who use a wide variety of machine tools. Over one million persons are employed as machinists, tool and die makers, instrument makers, machine tools operators and set-up and layout people.
The principle job of most machine workers is to operate machine tools. The most common types of machine tools are lathes, grinding machines, milling machines, broachers, saws, EDM (Electronic Discharge Machining) and either conventional or CNC (Computer Numerical Control) machines.

Accuracy is of prime importance for most precision machining work. Machining workers follow directions generally given in the form of a blueprint. Precision measuring instruments are used to check the accuracy of work against the blueprint specifications.
There are many advancement opportunities for experienced machinists. Many become foreman; others may, with specialized training, become tool and die makers. Machine Tool Technology is the basic background for quality control, metallurgy, programming CNC equipment and many other machine related fields.