REVERSING DRILL Russian patent published in 2003 - IPC

FIELD: metal working, tool making industry branch. SUBSTANCE: reversing drill includes symmetrical vanes with guiding strips; cuttings removal grooves and cutting blades with back faces inclined relative to drill apex by angle measured in plan view and forming cutting edges at both sides at crossing with cuttings removal grooves. Back faces of cutting edges are flat ones and they are arranged normally relative to symmetry plane of similar vanes. Outer surfaces of vanes between guiding strips may be flat ones and normal relative to symmetry plane of similar vanes. EFFECT: improved strength and stability of cutting blades, simplified process for making drill, simplified procedures for sharpening and resharpening drill. 2 cl, 4 dwg