| 摘要 |
The element has a rotation-transmitting unit (13) provided at one end (14) of a shaft (12). The shaft has a free end (16) remote from the rotation- transmitting unit. A tapping thread (21) carried by the shaft includes a screw thread (22) with a thread pilot located in a region (15) of the shaft free end. A section has a set of thread steps (25, 26) with a cross-section of the screw thread. The thread steps have respective cutting edge-forming end surfaces aligned in a direction of the thread pilot. |
