Cut the plywood into a rectangular piece that is 3 feet long and 2 feet wide.
Place one set of the skate dolly wheels on the plywood board. Adjust the position of the wheel set until the center is 3 inches from the side of the board and 3 inches from the top of the board. Trace the four holes in the wheel set onto the plywood board in order to mark its position for drilling. Repeat this step on all four corners of the plywood board.
Drill 16 holes into the plywood board, using the traced hole markings as guides.
Align one set of skate dolly wheels onto a corner with four drilled holes. Insert four bolts through the wheel set and through the plywood. Place a washer, then a nut, on each bolt sticking through the plywood. Repeat this step for each corner of the plywood.
Tighten each nut on every bolt of the dolly.
Lay the two PVC pipes parallel to each other with a distance of 18 inches between them. Set the plywood on the PVC "track," wheels down. Place the tripod on top of the platform.