Measure and cut four sheets of 1-inch thick plywood 28 inches long by 13 inches wide, using a tape measure and a circular saw. Cut one sheet of 1-inch thick plywood 27 inches long by 13 inches wide. Cut one sheet of 1-inch thick plywood 13 inches long by 13 inches wide.
Set the 1 inch pilot bearing in the router. Measure 14 inches along two of the 28-inch long sheets. Draw a line parallel with the 13-inch long edges on both sheets at this point, using a pencil and ruler. Cut a 1/2-inch deep groove in both sheets using the router with one edge of the groove running along the pencil line.
Set the 1/2 inch pilot bearing in the router. Cut a 1/2-inch deep groove along each 13-inch edge of the four 28-by-13-inch pieces, using the router. Each 28-by-13-inch sheet will each have one 28-by-13-inch face and one 27-by-13-inch face with a 1/2-inch wide, 1/2-inch deep groove along each 13-inch long side.
Apply wood glue to the 13-inch long ends of the 27-by-13-inch plywood sheet. Slide the glued sheet into the grooves on the two 28-by-13 inch sheets with grooves cut in their middles, to form an “H” shape. Apply wood glue to the notched ends of the 28-by-13-inch sheets.
Stick the remaining notched 28-by-13-inch sheets to the ends of the “H” so the notches meet, forming the cabinet frame. Measure 13 inches along the bottom of the frame from the bottom-left inside corner of the cabinet. Mark this point with a pencil. Glue the 13-inch long ends of the 13-by-13-inch sheet. Slide the sheet into the frame at the pencil mark point.
Reinforce each joint in the frame using a hammer drill with screwdriver drill bit to countersink three long screws in each joint. Paint or varnish the cabinet using a paintbrush, so it blends in with the colors of the furniture in the room where the cabinet is to stand. When the paint or varnish is dry, slide the record player into the shelf at the top of the cabinet.