| 摘要 |
The lips I, II, III of a twist drill, here designed as a three-lipped drill, are subdivided by chip-breaking flutes (15) running transversely to the lip into individual lip elements (16) which are provided with gaps in between and release individual narrow chips. The latter are broken into segmental chips which can easily be conveyed further. The respective three flutes (15 and 153) of the lips I and III pass through approximately the same surfaces of revolution, between which the surfaces of revolution of the chip-breaking flutes (15) fit. This also applies to the circumscribed circles of the lip elements (16) of the lip II relative to I and III. The individual lips can be replaced according to the representations I1 to I7 by such according to the representations under the three lips I, II and III. The width and arrangement of the chip-breaking flutes (15, 152, 153) can be matched to one another in such a way that the torsional moment acting on the twist drill acts symmetrically to the drill axis. <IMAGE>
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