Product Description              Irwin 10234 Unibit #4 12-Step High Speed Steel 3/8-inch Step Drill Bit, 1/16-inch Steps (3/16- to 7/8-inch) Save time by eliminating the need to change drills when drilling round holes in thin materials. Each smaller size drill also acts as a pilot for the next size. Made from industrial-grade high-speed molybdenum steel heat treated for maximum durability. Ideal for drilling holes into thin materials such as stainless steel, copper, brass, aluminum, plastic and laminates. SpeedPoint tip penetrates faster than previous Unibits and prevents walking. Non-skid tip does away with the need for center punches; 3-faltted hex shank prevents slipping in drill chuck. Drill diameters etched in flute for easy identification. Backed by a full lifetime warranty.                 Amazon.com              The Irwin 10234 UniBit #4 12-Step High Speed Steel Fractional Self-Starting Step Drill has a single-flute cutting edge to give you more control and produce true, round holes. Twelve holes range from 3/16 to 7/8 inches, in 1/16-inch increments. A non-skid tip does away with the need for center punches, while the three flatted shanks prevent slipping in the drill chuck. This drill is made from industrial-grade high-speed molybdenum steel heat treated for maximum durability, and it is ideal for work on thinner materials. The multiple steps mean you don't have to have a toolbox with specific size drill bits, and this drill is backed by a full lifetime warranty.                        From the Manufacturer              The #4 UniBit Step Drill has 12 holes--3/16-inch to 7/8-inch hole sizes with increments of 1/16-inch- shank size is 3/8-inch. Each UniBit step drill has an easy-to-sharpen, non-skid tip which eliminates skidding and the need for center punching; the tip gives sure starts even on curved surfaces. The single-fluted cutting edge that you will find on the UniBit step drills helps assure true round holes and allows greater control. They are constructed of industrial grade high speed molybdenum steel and heat treated to assure maximum durability. The UniBit step drill has 3 flatted shanks, which prevents slipping in drill chuck. The multiple steps on each UniBit eliminates the need to maintain a toolbox full of specific size drill bits. Full lifetime warranty--each UniBit step drill is warranted to be free from defects in material and workmanship for the life of the tool, except for damage caused by abuse, misuse, or alteration.               See more

• Save time because you don't need to change drills for different-sized round holes in thin materials. Each drill acts as a pilot for the next size.
• Made from industrial-grade high-speed molybdenum steel heat treated for maximum durability. SpeedPoint tip penetrates faster and prevents walking.
• Ideal for drilling holes into thin materials such as stainless steel, copper, brass, aluminum, plastic and laminates.
• Non-skid tip, no need for center punches. 3-faltted hex shank prevents drill chuck slipping. Drill diameters etched in flute for easy identification.
• Backed by a full lifetime warranty. B00004THZ0