Keyway punch nibbler, 3.5 mm mild steel. Eliminates time-consuming hand sawing and filing when making keyways for push-button switches. Punches 1/8 inch (3.2 mm) or 3/16 inch (4.8 mm) keyways for 7/8 inch (22.5 mm) or 1-7/32 inch (30.5 mm) push-button holes.