IRWIN Unibit 15104 Self-Starting Step Drill Bit, Tree Flute, Round Shank, 3/8 in Dia 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.