Tonight we have dinner guests and will use a table on the patio. It normally seats six. We need to seat twelve at this table.
+one sheet 3/4 x 48 x 96 inch chipboard
+1/4 inch dowel rod
+two 1 x 2 x 51 inch pine connecting rails
+six 1/4 x 20 Tee nuts
+six 1/4 x 20 x 1 1/2 inch bevel head screws
dowel jig and dowel centers
drill and bit
Step 1: Our Better Table
What this Instructable demonstrates is usually used on this better table inside.
Step 2: The Pieces
The sheet of chipboard has been cut into three equal pieces. You can also see the two connecting rails from solid pine (1 x 2 x 51 inches).
Step 3: Rounding the Corners
Use a plate or a paint can to scribe an arc on each of the four outer corners and round them with a saber saw.
Step 4: Doweling Tools
I am fortunate to have a Stanley doweling jig. I also use some Craftsman dowel centers. The combination of these two allows me to get holes that align with each other and are true.
Step 5: Drill for Dowels
I placed a dowel about every five to six inches. I rounded the ends of the dowels so they mate more easily with their holes when it is time to set up the table extension. Glue the dowels into one section of the expansion. I marked the pieces with letters so there is no question about which piece mates to which piece. These markings will be hidden under the tablecloth.
Step 6: When Joined
After aligning the dowels with their holes, just lean over the table and pull the sections together. The surface of the table is very smooth when the pieces are joined together. No one's plate rocks when they cut their meat with a knife and fork.
Step 7: Mark Rails
Mark the rails so there is no question later which face contacts the underside of the table and which edge faces inward. This will make the setup faster and easier in the future.
Step 8: Drill and Mark Holes
Place a rail under one edge of the table. Align its center with the center of the middle piece of chipboard. Clamp the rail to the table. Drill a 1/4 inch hole through the chipboard and the rail. Countersink the hole in the chipboard for the screwhead. Add a Tee nut to the rail from below. Drill a hole near to each end of the rail. Countersink and add a Tee nut as before. This insures the screw holes align perfectly. Mark the holes with corresponding numbers further to assist with the setup in the future. The holes in the other rail may not exactly match the holes in the first rail, but this does not matter, since each rail is marked so you know on which side of the table it belongs.
Step 9: Tee Nuts
The Tee nuts are also useful for storing the screws and insuring none of the Tee nuts are lost.
Step 10: Ready for the Tablecloth
Here is the table with the expansion ready for use. You can see it will now seat twelve. Just add a nice tablecloth. When not in use, the pieces store nicely behind a cabinet in a small anteroom. Be careful if storing near to a potential source of water, like a washing machine. Chipboard swells badly when wet and you will need to do some work with a sander after it dries in order to restore the smooth fit on the table's top. (Guess how I know!)
This table expansion sets up in just a few minutes. Guests never suspect they are eating from the top of a home built table expansion.