A professional who assembles barrel, setting lever, ratchet wheel, and barrel bridge to pillar plate to form barrel-bridge assembly, using watchmaker's tools, loupe, and holding fixture. Responsibilities include:

• Positions pillar plate on holding fixture and places barrel in plate recess, using tweezers and loupe.
• Screws barrel bridge with assembled crown wheel and click (pawl) in position over barrel and screws setting lever and ratchet wheel in place, using screwdriver.
• Holds ratchet wheel in position and tightens ratchet screw, using screwdriver.
• Positions clutch wheel and winding pinion in place and inserts stem through hole in pillar plate to secure assembly, using tweezers and loupe.