Give an old table a new lease on life by fitting it with a new, round plywood top. You can also increase the size of a table by fitting it with a larger top. If you have an old round or square table with solid legs, you can replace the top with a new one, which you can then stain or paint to complement the legs. This technique won't work with a rectangular base as the base won't be central beneath the top. When making the new top, make sure that it's large enough to cover the legs and provide sufficient leg room.
Decide on the size for your new table top. The top should overhang the base by no more than 18 inches or it may become unstable. Measure the diameter required.
Tie a piece of twine to a pencil. Measure the sheet of plywood to find the exact center. Trim the length of twine to the same measurement as the radius of the round top, and stick a thumbtack through the end of the twine into the center of the plywood. Draw a circle.
Cut carefully cut out the circle with a jigsaw. Sand off any rough edges, and make any corrections to the shape.
Fit the table top to the base. You may be able to reuse the old screw holes, in which case you can just fit the new top to the base and screw it in position, making sure that it's centered. Otherwise, put the top in position and drill through the table top into the corner of the base. Put in a screw through the top and into the base. Repeat for the other corners.
Fill the screw holes with wood filler. Allow to harden, then sand down level with the table top. Paint or stain the table top or the whole table to give it a more attractive finish.