Irwin Unibit 15103ZR Step Drill Bit, 1/4 to 3/4 in Dia, 2-1/2 in OAL, 1-Flute, 3/8 in Dia Shank, Hex Shank

Self-starting bit features single flute cutting edge for greater control through steps. Three flatted shanks prevent slipping in drill chuck. SpeedPoint tip penetrates faster and prevents walking in applications such as drilling holes into stainless steel, copper, brass, aluminum, plastic, laminates and other thin materials up to 1/8 in thick.