Bosch step drill hss triangle shank bosch 2608587428 these hss step drills from bosch have triangular shanks step drill bits hss 12 steps diameter 6 9 125 152 186 204 225 26 283 305 34 37 pg7 pg9 pg11 pg135 pg16 pg21 pg29 bosch 2608587428 step drill hss triangle shank 6 37mm pg7 pg29 x 93mm