Abstract: A drill bit (20, 420, 520, 620, 720, 820, 920, 1020) is provided that includes a connector (32, 232, 532, 632, 732, 832, 932, 1032), which includes a shank (34), configured to receive torque; a proximal electrically-conductive coupler (36, 436, 536, 636, 736, 836, 936, 1036), which is disposed at a distal end (28) of the shank (34), rotationally fixed with respect to the shank (34); and a distal electrically-conductive coupler (38, 238, 438, 538, 838, 738, 838, 938, 1038). The distal electrically-conductive coupler is rotationally fixed with respect to the proximal electrically-conductive coupler, electrically isolated from the proximal electrically-conductive coupler, and shaped so as to define a distal-electrically-conductive external contact surface (62, 862, 962, 1062). The drill bit further includes a drill shaft (30, 130, 230, 330, 430, 830) including an electrically-conductive outer electrode (44) and an electrically-conductive inner electrode (46, 146, 246, 346, 846).