Cut a sheet of 3/4-inch plywood into a rectangle the size you want for the tabletop using a saw. Skip this step if you want to use the entire sheet for the tabletop.
Cut the plywood in two, creating two equal panels. For example, a 3-by-8-foot table top would become two 3-by-4-foot panels.
Lay the panels on the floor with the cut ends butted up against each other.
Place two 3-inch hinges on the cut, with one wing on each piece.
Screw the hinges to the plywood with 3/4-inch wood screws. The thickness of the wings will prevent the screws from penetrating the table surface.
Place a 1-inch threaded flange on each corner of the table, positioned an inch in from the corner.
Attach the flanges to the table with 3/4-inch wood screws.
Screw four threaded pipes into the four flanges. The pipes should be as long as you want the table to be tall.
Set the table on its legs. Unscrew the legs and fold the table in two to transport it.