Abstract: A protruding head fastener incorporates a slight head taper that gradually increases in diameter as it moves in the opposite direction from the female threaded section formed in a parent material. The fastener head engages the mating non-tapered counterbore located in the parent material, the counterbore being slightly larger than the outside diameter of the tapered head portion of the fastener closest to the threads and slightly smaller than the outside diameter of the outward taper of the fastener at the farthest position away from the threads. As the male fastener engages the female threads, the taper of the head of the male fastener abuts against the non-tapered counterbore of the parent material. An interference condition occurs and the mechanical advantage of the threads rotationally pull the tapered head into the counterbore. The counterbore material then begins to yield and deform slightly to conform to a precise matching taper fit with the head of the male fastener.