A professional who attaches stud to watch hairspring preparatory to assembly to balance bridge, using studding fixture, loupe, and watchmaker's tools. Responsibilities include:

• Positions stud in recess of studding fixture, using tweezers, and broaches hole in stud, using handtool.
• Inserts end of outer hairspring coil into hole, and forces tapered brass pin through hole to wedge spring in place, using loupe and watchmaker's tools.
• Cuts off protruding ends of pin, using pliers.