Roof drilling bit, roof drill bit body undharter cutting insert for the roof of the borehole surface and the chisel

摘要

A roof drill bit (18) has an elongated roof of a drill bit body (20) with a front end (22) and a rear end (24) on. The roof of a drill bit body (20) includes a slot (28a) to the front end (22). The roof of a drill bit body (20) contains a dust duct (50a, 50b), wherein the dust duct (50a, 50b) a central dust along axis (d - d) has. The roof has, furthermore, a drilling bit in the slot (28a) recorded hard metal insert (72), wherein the hard metal insert (72) a front surface (82) comprises. The front surface (82) of the bit (72) is rotationally in front of the central dust along axis (d - d) of the dust channel (50a, 50b).