A percussion or hammer drill is provided including a drill plate arranged
in the head end of a drill shaft, extending completely across the
diameter of the drill shaft and comprising an open front face.
Wedge-shaped cutting edges and flanks form two main cutters on the front
face, whereby a plane running through the drill axis forms a mid-plane-of
both main cutters. The main cutters form a tip angle in the range of
approximately 140.degree. to 180.degree. and are separated by a central
point.