Features The shanks on these step drill bits have three flats that help prevent the bits from slipping in the drill chuck during drilling. These cone-shaped bits have steps of increasing diameter marked along their cutting head. As each bit is pushed into a piece of sheet metal or other thin material, each step on the bit widens the hole. The bits also have a self-starting split point that prevents the bits from moving, or walking, when starting to drill, which eliminates the need for using a center drill to create a starter hole before drilling. Number Hole Sizes / 8 Minimum Hole Size / 9/16 in Maximum Hole Size / 1 in Material - Machining / High Speed Steel Drill Bit Sizes Included / 9/16 in, 5/8 in, 11/16 in, 3/4 in, 13/16 in, 7/8 in, 15/16 in, 1 in Decimal Equivalent / 0.5625, 0.625, 0.6875, 0.75, 0.8125, 0.875, 0.9375, 1 Measurement System / Fractional Inch Step Increments / 1/16 in Shank Type - Machining / Straight with Three Flats Shank Diameter / 3/8 in Overall Length / 2 7/16 in Maximum Drilling Depth / 1/8 in Finish - Machining / Black Oxide Impact Rated / No Primary Material Application / Aluminum, Brass, Copper, Laminate, Plastic, Steel, Wood Series / UNIBIT Sub Brand / Unibit