An intramedullary device to repair a bone in a mammalian body and comprising an elongate nail having a stem and a head. The head is provided with a transverse aperture adapted to receive a fastener. An adjustment mechanism is carried by the head for pivoting the fastener from a first angled position relative to the head to a second angled position relative to the head. A set screw is carried by the head. The distal end of the set screw is movable relative to the proximal end of the set screw from a first position for lockably engaging the fastener in the first angled position and a second position for lockably engaging the fastener in the second angled position. A sealing cap and an apparatus having a cap and a set screw are additionally provided.