Abstract: A pin mounts a plurality of expandable and contractable bushings that upon expansion engage the bore of workpieces to hold the latter together. A ball lock expands behind the workpieces to present a positive lock against axial pullout of the fastener. The bushings are alternate male and female, split ring bushings that have complementary contiguous surfaces that act as wedges. Upon axial compressive loading the female bushings expand and the male bushings contract. The ball lock includes a pair of diametrically opposed balls radially displaceable in the pin. A slide has an annular recess for receiving the balls in a withdrawn position within the pin. A spring normally biases a land of the slide into a position radially inside the balls to rigidly hold the balls in their extended position.