IRWIN Step Drill Bit: 1/4" to 1-3/8", Black Oxide HSS, Hex Shank

These high-speed steel step drill bits create perfectly round holes in a range of sizes without requiring multiple bits to be swapped out in the drill. These bits can also be used to enlarge and debur existing holes, and are suitable for drilling thin materials up to 1/8" thick. High Speed Steel drill bits absorb more shock and vibration than cobalt and carbide, making them suitable for use in manual drilling machines and handheld power tools. Black Oxide coating improves lubricity to reduce friction, minimize heat buildup, and improve wear resistance, chip flow, and tool life. It is a good choice for general purpose drilling and working with soft materials, such as plastic and low-carbon steel, and should not be used with aluminum and nonferrous metals. Hex Shank drill bits have six flat sides that prevent the bit from slipping in high-torque applications. Hex shanks install in standard drill chucks.