Method of making a fastener

The method of using a cylinrdical ram to precision-form an outwardly open cupped fastener at a predetermined location on one side of a sheet of porous substrate material, which method comprises applying a premeasured quantity of plastic working material to said one side at said location, establishing an enclosed volume adjacent to and surrounding said location and said plastic working material on said one side, said enclosed volume being completed in part (a) by circumferentially continuous annular sealing compression of said substrate material against a reaction anvil on the other side of said substrate material, the sealed annulus defining an inner uncompressed area of substrate material exceeding the sectional area of the ram, said enclosed volume being further completed (b) by circumferentially continuously sealed sliding engagement to the cylindrical surface of the ram on an axis normal to the substrate material at said location, then compressionally defomring the premeasured working material aganist said one surface and against anvil reaction by direct vibratory driven contact of the inner end of the ram with the working material to melt the same and force its impregnation of substrate pores within the compressionally sealed annulus, the premeasured quantity of working material being greater than that required for such porous impregnation, whereby excess plastic working material remains at said one surface after local porous impregnation of the substrate, and die-forming the fastner from excess plastic material within the enclosed volume by inwardly displacing and vibrationally driving the ram to the extend achieving an outward dispalcement of working material into circumferentially continuous axial overlap of the inner end of the ram.