STEP DRILL BIT

A step drill bit (10) comprising: a shank (12) extending along a bit axis (14); a body (18) having a proximal end (19A) adjacent the shank and a distal end (19B) opposite the proximal end, the body defining a plurality of axially stacked, progressively sized steps (20A - 20M) including a first step (20A) at the distal end, a terminal step (20M) at the proximal end, and a plurality of intermediate steps having incrementally increasing diameters disposed between the first and terminal steps; a flute (46) in the body, the flute defining an elongated groove that extends from the distal end to the proximal end; and a plurality of cutting edges (64A - 64M) formed in the body, each cutting edge disposed along one of the plurality of steps, each cutting edge defining a helix angle (68C) and a rake angle (66C, 66M); wherein the helix angle of the cutting edge at the terminal step is greater than the helix angle of the cutting edge at the first step; and wherein the rake angle of the cutting edge at the terminal step is greater than the rake angle of the cutting edge at the first step.