A step drill bit includes a shank and a body having a proximal end adjacent the shank and a distal end opposite the proximal end. The body defines a plurality of axially stacked, progressively sized steps including a first step at the distal end, a terminal step at the proximal end, and a plurality of intermediate steps having incrementally increasing diameters disposed between the first and terminal steps. The step drill bit also includes a plurality of cutting edges each disposed along one of the plurality of steps. Each edge defines a helix angle and a radial rake angle. The radial rake angle and the helix angle of the cutting edge at the terminal step is greater than the radial rake angle and the helix angle of the cutting edge at the first step.