Overview Reviews Product Description Irwin Unibit® step drill bits are ideal for drilling holes in just about any type of thin material.General purpose high speed steel Unibit® step drill bits are perfect for use in mild steel, copper, brass, aluminum, plexiglass, wood, and laminate.Most Unibit® step drills are designed with a speedpoint tip that guarantees fast starts.Theyre manufactured with a single flute cutting edge that drills multiple sizes of true, round holes with precise step control.Plus, the hole sizes are permanently laser etched on the inside of the flute, so they can be easily identified throughout the life of the bit. Irwin Tools Catalog Product Videos Custom Field Manufacturing country US Product Reviews Write a Review Write a Review × Irwin UNIBIT® 3 - 6mm Cobalt Alloy Steel Step Drill Bit 11103 Rating * Select Rating 1 star (worst) 2 stars 3 stars (average) 4 stars 5 stars (best) Name Review Subject * Comments *