| 摘要 |
1,205,060. Drills. BARWORTH FLOCKTON Ltd. 24 Sept., 1968 [10 Oct., 1967], No. 46235/67. Heading B3C. A drill 1 has a series of cutting diameters 5, each of which has three cutting edges formed by three flutes 9, and a pilot drilling end 14. A series of such drills may be provided having cutting diameters of from 7/32 inch up to 1<SP>37</SP>/64 inches in steps of <SP>1</SP>/ 64 inch. A set of metric drills may be provided having cutting diameters from 5À5 mm. to 38 mm. in steps of 0À5 mm. |
