A professional who smooths, drills, and tests parts of diesel engine fuel injectors based specifications, using lapping machine, microscope drill, and equipment for tests. Responsibilities include:

• Mounts injector check valves on spindle heads.
• Smooths flat and curved surfaces of valves on rotating disk or semi-spherically shaped pan containing lapping compound for specified time.
• Examines samples of lapped valves under binocular microscope for nicks and grooves.
• Clamps injector spray tip in fixture under microscope drill and moves lever to drill holes into tip.
• Stamps identifying numbers on injector parts, using roll type metal stamper.
• Clamps body of injector into holding fixture and inserts tip assembly including check valve, barrel and plunger, stem, spring, and retaining nut.
• Screws injector into testing machine and moves lever to test operation of plunger, spring, and spray tip outlets.