| 摘要 |
<p>A twist drill (10) having a body (12) with helical lateral cutting @edges@ (15) and end cutting edges (18) located at a working end (18) of the body (10) has ducts (26) opening into this working end (18) for supplying a lubricating and cooling fluid. Each duct (26) is defined by a helical groove (32) formed in the back (15a) of a respective lateral cutting edge (15) and by a cover strip (34) for the groove (32).</p> |
