Abstract: The disclosed self-fastening nut includes a rectangular flat end face which is received against the panel, a smooth cylindrical central bore perpendicular to the end face and a pair of linear grooves equally spaced from the bore and dividing the end face into a central pilot and a pair of flanges. The nut is assembled on a cylindrical punch which extends through the nut bore, beyond the end face and punches a hole in the panel in registry with the nut bore. The panel is supported on a die having two upstanding clinching lips which deform the panel into the nut grooves and the panel is simultaneously urged against the nut to lie flat against the end face.