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. Our titanium nitride coated (TiN) bits resist heat and friction, which extends the life of the cutting edge six times longer than standard step drills. And our cobalt Step Drill Bits are engineered with M35 cobalt steel for maximum life when drilling in the toughest steel, including stainless steel. Most Unibit® step drills are designed with a SpeedPoint® tip that guarantees fast starts. They're 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® Unibit®, 10234CB, Step Drill Bit, Imperial, #4 Letter/Wire, 3/16 in Diameter Minimum Hole, 7/8 in Diameter Maximum Hole, 3-1/4 in Overall Length, 12 Steps, 1/16 in Step Depth, 12 Hole, 1 Flutes, 12, Radial Concave Flute, 3/8 in Shank, Hex Shank, SpeedPoint®, M35 Cobalt HSS Cutting Edge, M35 Cobalt HSS, Oxide Treated, Applicable Materials: Stainless Steel and Steel