| 摘要 |
A threaded fastener of the self-tapping type is described having the conventional head, shank, and pilot end. The shank includes a helically wound thread member impregnated with a carbide or other, harder substance than the metal from which the fastener is made. A thread-cutting fastener, having its pilot tip end impregnated is also described. A thread-rolling machine with a unique impregnating electrode is disclosed. The electrode is shown to engage the fastener selectively during the thread-rolling operation itself. A method of manufacturing or forming the threaded fastener is described whereby a tough, ductile fastener is shown having superior reciprocal or mating thread forming and cutting characteristics. |
