| 摘要 |
The drilling tool consists of a clamping shank, a short transition part adjoining the clamping shank, and an essentially cylindrical cutting part (3) which has two diametrically opposite flutes (8, 9) twisted through less than 360 DEG , two webs (10) remaining between the flutes (8, 9), and two interchangeable cutting tips (6, 7) at its front end, which cutting tips (6, 7) are arranged offset from one another by about 180 DEG in the peripheral direction in each case at different radial distances from the drill axis (A). The flutes (8, 9), starting from the front end of the transition part towards its rear end, have a decreasing depth and run out at the rear end of the transition part in its circumferential surface. The helix angle of the flutes (8, 9) increases from the front end of the cutting part (3) towards its rear end. The helix angle (ss1) is selected to be so large in the rear area of the cutting part (3) that, at the front end of the transition part, where the flutes (8, 9) still have their full depth, the centre line (M), running through the cross-section there (connecting cross-section) of the cutting part (3), of each of the two webs (10) runs approximately in the direction of the overall resultant (FR) of the cutting forces (F1, F2) acting on the cutting tips (6, 7). <IMAGE>
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