A professional who assembles, inspects, and adjusts watch train (center, third, fourth, and escape wheels with pinions), using watchmaker's tools, loupe, and holding fixture. Responsibilities include:

• Examines parts to ensure freedom from defects, using loupe.
• Positions pillar plate in holding fixture and inserts pivots of wheel staffs into holes drilled in pillar plate jewels, using tweezers.
• Positions train bridge over wheels, aligns pivots with jewels in bridge, and screws bridge to pillar plate, using tweezers and screwdriver.
• Inspects assembled watch train for meshing of wheels and pinions and endshake (vertical play) of wheels, using tweezers and loupe.
• Moves jewelled bearings specified distance to correct deficient endshake, using micrometre and hand staking tool.