FASTENER AND DRIVER COMBINATION

摘要

A combination of a cruciform recess in a fastener and cruciform driver has driver wings 13 which are narrower than corresponding recess radial grooves 21 and has downwardly tapered grooves and wings such that driving engagement between driver and fastener takes place at the outer upper edges of the recess. There is a relative downward taper between the wing width and groove width and these widths are so selected that the lower ends of the wings are confined by and preferably wedge in the recesses.