Method of manufacturing a piece of nuts and bolts, tool for implementing the method and device for screwing and then of such a piece of fastenings

摘要

The present invention relates to a process for manufacturing a piece of nuts and bolts, such as a screw (10) or a nut, comprising a head (12) comprising a rim (18) comprising at least one shoulder (20) extending in a radial plane. The method comprises at least the following form: shearing of a wire of material (38) so as to obtain a piece of a given length, the calibration of the part so as to correct the geometry of the part of the calibrated part (34), so as to obtain the head of the piece of nuts and bolts, and the finishing of the piece formed by means of a third punch (36) so as to form a head comprising at least one shoulder (20), the steps of the calibration, roughing and finishing being made solely by cold rapping.