A professional who tests and adjusts barrel endshake (vertical clearance of arbor between cover and bottom of barrel), using holding fixture and jeweler's tools. Responsibilities include:

• Places barrel assembly in holding fixture and moves arbor up and down to test endshake, using tweezers.
• Estimates from experience whether shake is within acceptable limits (between 0.015 and 0.02 mm).
• Actuates arms of holding tool to bend barrel cover sufficiently to correct endshake error.