| 摘要 |
1463785 Spade drills STANLEY WORKS 7 Feb 1975 [11 Feb 1974] 5270/75 Heading B3C A spade drill bit 10 comprises a shank 12 a flat blade 14 and a point element 16 which has converging faces 54, 56 and side edges 58, 60, Figs. 3 and 6. Edges 58, 60 are in the form of bevels so that the element 16 is thomboidal in cross-section. The element may be undercut at 50, 52. Blade 14 may also have similarly bevelled edges 34, 36, 42, 44 and the leading edges may be inclined to the bit axis, Figs. 1 and 6. A hole 64 may be provided for storage purposes. |
