Flip the table over so the tabletop faces down and the legs stick up in the air.
Measure the width of the tabletop between the apron.
Cut a piece of 2-by-2-inch lumber to fit the width measurement within the apron.
Apply a bead of wood glue to one edge of the 2-by-2 and set it in place in the center of the table. Tap the board in place with a hammer if the fit is tight.
Allow the glue to dry according to the manufacturer's instructions.
Drive 2-1/2-inch wood screws through the 2-by-2 to secure it to the tabletop; space screws about 3 inches apart. Drive an additional screw at an angle through the 2-by-2 and into the table apron on each end.
Measure the space between the 2-by-2-inch board and the table apron; the measurement runs perpendicular with the previous measurement, along the length of the table.
Cut two 2-by-2-inch boards to fit the space between the existing 2-by-2 and the table aprons.
Apply glue to one side of each board and glue in place, centered on the existing 2-by-2. When finished, the three 2-by-2-inch boards form a t-shape.
Allow the glue to dry.
Screw the 2-by-2-inch boards to the table top with 2-1/2-inch wood screws spaced 3 inches apart. Drive a screw in at an angle at each end of the 2-by-2s to secure them to the table apron and to the existing 2-by-2.