A fastener includes a nut having an anterior portion, a posterior portion and a threaded bore with a center axis extending from the anterior portion to the posterior portion, the outer surface of the posterior portion having an annular camming surface concentric with the center axis, the camming surface having a radius that decreases along the direction of the center axis away from the anterior portion toward the posterior portion; and a sleeve having a first end having an internal annular camming surface that engages the nut camming surface concentrically with the center axis and a second end having a thrusting surface. Tightening the fastener on an externally threaded member applies a force to the thrusting surface parallel to the center axis resulting in the nut camming surface and the sleeve camming surface cooperating to compress a portion of the threaded bore toward the threaded member.