| 摘要 |
<p>The grub screw comprises a conventional threaded cylindrical body (1), with a rear slotted end (2) for engagement with a screw-driver, either formed or not with an enlarged head. The front piercing end is formed as a milling cutter, i.e. it comprises a diametrical frusto-conical notch (3) or suitable depth and upper cutting edges to ensure a milling action. The front piercing end may be of convex configuration with a diametrical frusto-conical notch of greater depth. Alternatively, the front piercing end may be of planar configuration, and is provided with two diametrical frusto-conical notches crossed to each other.</p> |
