| 摘要 |
<p>ROCK DRILL BIT A rock drill bit consisting of a metallic body portion of steel having a peripheral front surface equipped with cylindrical hard metal inserts that protrude from interferringly sized cylindrical holes in said body portion. The wall portions of the insert-receiving holes are provided with laterally recessed portion at the transition regions between the cylindrical wall and the bottom of said hole such that the lowermost cylindrical mantle surface of each insert is freely exposed relative to said cylindrical wall portion of said hole.</p> |
