| 摘要 |
A wood drill (1) with a point (2), cutting lips (24) at the point (2), a shank (3) and a body (4). The body (4) has lands (9, 10) defining between them flutes (14, 15). The flutes (14, 15) have a high helix reach extending from a distance from the cutting lips (24) toward the shank (3), an intermediate helix reach extending from the high helix reach toward the shank (3) and a low helix reach extending between the intermediate reach and the shank (3). The drill (1) has screw threads (30) in a peripheral surface of the lands (9, 10) from a point adjacent the cutting lips (24) a distance toward the shank (3) less than the length of the high helix reach of the flutes (14, 15). |
