A professional who attaches cap jewel plate to train and balance bridges. Responsibilities include:

• Places bridge in holding fixture and positions cap jewel plate over bridge, aligning cap jewel with hole in bridge.
• Inserts minute screw into hole with tweezers and screws plate to bridge.
• Observes minute parts with loupe.
• May insert screw in hole of balance bridge to facilitate subsequent fastening of hairspring stud.