| 摘要 |
The invention relates to a dual-cutting drilling tool. The drilling comprises a base body ( 14 ) which is rotatable about a drill axis ( 36 ) and in which two plate seats ( 16 ) are arranged on the front face thereof for receiving identically configured alternating cutting plates ( 16 ). The alternative cutting plates are respectively provided on a main cutting edge ( 28 ) thereof with an adjacent first face ( 30 ), forming a cutting wedge, and a free surface ( 24 ). The main cutting edges ( 28 ) of the alternating cutting plates ( 20 ) complement each other in the region of a central, offset cutting part ( 28 '), forming a cross-cutting edge which is interrupted by a center hole ( 60 ). The aim of the invention is to reduce the risk of breakage in the center area of the alternating cutting plates and to provide better guidance for the tool. According to the invention, slanting guiding inclinations ( 56 ) are provided on the free surface of the alternating cutting places ( 20 ), extending from an apex line ( 54 ) to the center corner ( 46 ) of the plates. The free surfaces ( 24 ) are positively inclined in a radially outer region in the direction of advancement and are negatively inclined in the region of the guiding inclinations ( 56 ) thereof.
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