A professional who fabricates, modifies, or repairs mechanical instruments or mechanical assemblies of electrical or electronic instruments, such as chronometric timing devices, barographs, thermostats, seismographs, and servomechanisms, applying knowledge of mechanics, metal properties, shop mathematics, and machining procedures and using machine tools, welding and heat-treating equipment, precision measuring instruments, and handtools. Respnsibilities include:

• Measures, marks, and scribes stock, such as silver, nickel, platinum, steel, ivory, and plastic, following blueprints and engineering sketches, and using square, rule, and scribe to lay out workpiece for machining.
• Sets up and operates machine tools, such as lathes, drill presses, punch presses, milling machines, grinders, brakes, and lapping and polishing machines, to machine parts to specifications.
• Anneals and tempers metal parts.
• Assembles parts in jig and brazes or welds.
• Fits and installs precision components, such as timing devices, springs, balance mechanisms, and gear trains, in housing, using jeweler's lathe, tweezers, loupe, and handtools.
• Verifies dimensions of parts and installation of components, using measuring instruments, such as micrometer, calipers, and electronic gauges.
• Coats assembled instrument with protective finish, such as lacquer or enamel, using spray gun.
• May install wiring and electrical components to specifications.
• May set up and operate machines to fabricate dies for punch presses.
• May be designated according to product assembled.