A professional who operates vertical- or horizontal-drill press to countersink drilled holes in watch parts. Responsibilities include:

• Places part in bed or chuck of press.
• Aligns countersinking bit and hole, using loupe, and advances bit manually to automatic stop device.
• Removes part from press and measures depth of countersink, using precision dial gauge.
• May countersink screw holes around periphery of balance wheels and be designated balance screw hole countersinker.