| 摘要 |
<p>An automotive oil sump has a metal drain plug with a threaded outer shank and a head containing a socket hole for the removal/tightening tool. In a process to manufacture the plug (10) a metal blank is cut with a head (12) and a cylindrical truncated pipe (26) with an inner diameter and outer diameter which is less than the finally envisaged dimensions (e, f). The truncated pipe (36) sidewall is then placed under inner pressure and widened.</p> |
