Irwin #20 Unibit Hole-Enlarging Stairstep Bit, 8-Step, 9/16" to 1" Dia, 1/8" Depth: * Get it all done with one when you choose Unibit stairstep bits * Single-flute cutting edge provides precise depth control though all size steps * Shank"s flat side surface ensures slip-free chuck lock-down * Blunt-tip, hole-enlarging bit may be used on stainless steel, copper, brass, aluminum, plastic, laminates and wood * Material(s): Steel * Drill Bit Range (Min): 9/16" * Drill Bit Range (Max): 1"