| 摘要 |
PCT No. PCT/EP92/01070 Sec. 371 Date Nov. 19, 1993 Sec. 102(e) Date Nov. 19, 1993 PCT Filed May 15, 1992 PCT Pub. No. WO92/20483 PCT Pub. Date Nov. 26, 1992.A drilling tool has a drilling crown (12) removably arranged on a shank (10) at its front face, provided with two complementary regions that are mutually separated by chip channels (20) and that have partially circumferential surfaces (48). The drilling tool also has at least two cutting plates (14, 14', 16, 16') secured to the regions of the drilling crown and spaced apart by an angle of 180 DEG , as well as a centering drill (26) centrally arranged in the drilling crown in the axial direction that projects over the front face of the latter. The cutting edge (18) of the outermost cutting plate (14) in the radial direction radially projects over the circumferential surfaces (48) of the drilling crown (18), whereas the working area of the innermost cutting plate radially approaches or overlaps the working area of the centering drill (26). In order to allow through holes to be cut without risk of damage, even in the case of deep holes, a guiding element (58) that radially projects slightly less than the cutting edge (18) of the outermost cutting plate (14) in the radial direction is arranged on both circumferential surfaces (48), axially spaced from the front face of the cutter and spaced apart from each other by an angle other than 180 DEG . |
