A professional who tends jigging machines that grind pivots of watch parts to specified lengths. Responsibilities include:

• Pulls spindle handle to open spindle, inserts pinion with tweezers, and releases handle to force pinion into place in chuck.
• Depresses pedal to start rotating grinding wheel across end of pivot to grind pivot to specified size.
• Measures pinions to ensure specified lengths, using loupe and precision upright gauge.