| 摘要 |
An elongate threaded fastener (50) for attaching the roofing panels (8) has a first part (20) and a second part (30), both made of a steel, and the first part (20) is composed of an elongate non-threaded shank (22) and a fastening rod portion (23) continuing from the shank and of a reduced diameter. The second part (30) is composed of an increased-diameter rod portion (35) and a head (36) formed at the proximal end of this portion. The first and second parts (20,30) are resistance welded together, before a boring means (24) such as a drill tip is formed on the distal end of the fastening rod portion (23). Then, both the fastening and increased-diameter rod portions (23,35) are rolled to form screw threads (23a,35a) respectively on them such that a method is provided to manufacture more efficiently at an improved productivity the threaded fastener (50) having the proximal threaded rod portion (35) whose diameter can be designed large enough.
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