| 摘要 |
Each tooth of an annular hole cutter is formed with at least three cutting edges (34, 36, 72, 82), each of which is designed to cut a separate chip. The two radially innermost cutting edges (34, 36) are formed on the portion of each tooth which corresponds to the thickness of the web between successive teeth. The web has a thickness which is preferably greater than the radial depth of the flute (22) between successive teeth, which is radially aligned with the web. These two cutting edges have respective gullets (44, 50) extending axially rearwardly of the teeth. The gullets have rearwardly outwardly sloping surfaces to direct chips into the flute. The flute rear face provides the outermost cutting edge or edges (72, 82), the outer of which may have a peripheral cut-away The flute is of greater depth than the innermost respective edges to allow chip passage. <IMAGE> |
