| 摘要 |
1,020,516. Drills. H. J. MAYNARD. April 23, 1963 [April 25, 1962], No. 15911/63. Heading B3C. A twist drill has at least two helical passages 18, 20 in each land for supplying pressurized mist coolant to the cutting edges 24, from one or more transverse inlet ports 22. The total cross-sectional area of the inlet ports is greater than the total cross section of passages 18, 20 at the drill tip, and passages 20 have cross-sectional areas which are less than the cross-sectional areas of passages 18. The drill is connected to a mist cooling system, Fig. 4 (not shown), wherein a mist forming station 30 is supplied with pressurised air by a conduit 32, and with a jet of water by a conduit 34. |
