A professional who tends semiautomatic mainspring-winding machine that winds mainspring into shell (barrel) and lubricates bearing surfaces. Responsibilities include:

• Opens chuck, inserts arbor, and fits spring assembly over arbor.
• Depresses pedal that allows winding and oiling mechanism to wind spring around arbor, and oil spring.
• Places barrel over spring by hand and removes assembly from chuck.
• May wind mainspring, using hand-operated spring-winding tool.
• May reverse mainspring to coil spring in direction used in watch and be designated mainspring-reverse winder.