Things You'll Need
Instructions
Assemble a square frame from the beams. Attach them with the 3-in. wood screws. Connect the beams so that the frame is 4 in. deep. If your beams are not precut, cut them into four 14-1/2-in. pieces.
Make the bottom of the box by attaching the plywood board to the bottom of the frame, using the 1-3/4-in. wood screws. If your plywood is not pre-cut, cut it into a 16 in. by 16 in. piece before attaching it to the frame.
Set an L bracket against an end of the PVC pipe to measure drill hole placement. Mark the hole position with a pencil. Measure four holes at 90-degree intervals around the circumference of the pipe. Drill the holes.
Attach the L brackets to the PVC pipe using the nuts and bolts. If necessary, tighten the bolts with pliers.
Find the center of the box using the measuring tape, and mark it with a pencil. Set the PVC pipe in the box bracket side down so that the center of the box is at the center of the circle. Attach the L brackets to the plywood base with four 3/4-in. wood screws.