| 摘要 |
A self-threading screw is described which includes a (basically) conical point set at the end of its shank opposite that where the head is housed, and a sunken zone set between the end of the screw shank and the conical point.In addition, an apparatus is described to produce a self-threading screw provided with a point and a sunken zone, in which at least the thread of the self-threading screw, the conical point and the sunken zone are simultaneously produced by rolling. |
