| 摘要 |
<p>A support tube for a tubular structure, such as a vertical post for a railing, a ladder step, or the like, has at least at one end a curved recess for receiving a cross tube. On the curved margin of the curved space, the wall of the supporting tube is bent to form a supporting flange. This is made by, prior to cutting the supporting tube to desired length, drilling a hole through the tube at the point where it is cut, and drawing out the margins of the hole to form a collar projecting from the support tube. The support tube is then cut off so as to divide the collar into support flanges, which remain on the ends of separate support tubes.</p> |
