Machinists typically do the following:

• Read blueprints, sketches, or computer-aided design (CAD) and computer-aided manufacturing (CAM) files
• Set up, operate, and disassemble manual, automatic, and computer numerically controlled (CNC) machine tools
• Align, secure, and adjust cutting tools and workpieces
• Monitor the feed and speed of machines
• Turn, mill, drill, shape, and grind machine parts to specifications
• Measure, examine, and test completed products for defects
• Smooth the surfaces of parts or products
• Present finished workpieces to customers and make modifications if needed

Tool and die makers typically do the following:

• Read blueprints, sketches, specifications, or CAD and CAM files for making tools and dies
• Compute and verify dimensions, sizes, shapes, and tolerances of workpieces
• Set up, operate, and disassemble conventional, manual, and CNC machine tools
• File, grind, and adjust parts so that they fit together properly
• Test completed tools and dies to ensure that they meet specifications
• Smooth and polish the surfaces of tools and dies

Machinists use machine tools, such as lathes, milling machines, and grinders, to produce precision metal parts. Many machinists must be able to use both manual and CNC machinery. CNC machines control the cutting tool speed and do all necessary cuts to create a part. The machinist determines the cutting path, the speed of the cut, and the feed rate by programming instructions into the CNC machine.

Although workers may produce large quantities of one part, precision machinists often produce small batches or one-of-a-kind items. The parts that machinists make range from simple steel bolts to titanium bone screws for orthopedic implants. Hydraulic parts, antilock brakes, and automobile pistons are other widely known products that machinists make.

Some machinists repair or make new parts for existing machinery. After an industrial machinery mechanic discovers a broken part in a machine, a machinist remanufactures the part. The machinist refers to blueprints and performs the same machining operations that were used to create the original part in order to create the replacement.

Some manufacturing processes use lasers, water jets, and electrified wires to cut the workpiece. As engineers design and build new types of machine tools, machinists must learn new machining properties and techniques.

Tool and die makers construct  precision tools or metal forms, called dies, that are used to cut, shape, and form metal and other materials. They produce jigs and fixtures—devices that hold metal while it is bored, stamped, or drilled—and gauges and other measuring devices.

Dies are used to shape metal in stamping and forging operations. They also make metal molds for die casting and for molding plastics, ceramics, and composite materials.

Tool and die makers use CAD to develop products and parts. They enter designs into computer programs that produce blueprints for the required tools and dies. Computer numeric control programmers, described in the metal and plastic machine workers profile, convert CAD designs into CAM programs that contain instructions for a sequence of cutting-tool operations. Once these programs are developed, CNC machines follow the set of instructions contained in the program to produce the part. Machinists normally operate CNC machines, but tool and die makers often are trained to both operate CNC machines and write CNC programs and thus may do either task.