A nondetachable fastening for sheet metals can be produced at optimum cost by using selfclinching screws under the brand names of RIVTEX® (for sheet thicknesses between 0.75 and 2.00 mm) and STRUX® (for sheet thicknesses between 2.0 and 5.00 mm). The clinching technology is suitable for steel and aluminium sheets, causes very little cost in inspection and control, and allows several clinch screws to be processed in a single stroke