Abstract: An internally expanding and locking apparatus for installing inside the pipe stub of a typical outdoor lighting pole and expanding with locking teeth to grasp the inner walls of the pipe stub, the apparatus including a swivel base, a clamp screw inserted through the swivel base, a ramp nut passing over the clamp screw so as to be positioned offset from the swivel base, and a mounting nut threadably installed on the clamp screw and configured to engage the ramp nut so as to control the position of the ramp nut relative to the swivel base as the clamp screw is rotated during use of the pipe mounting apparatus.