Futons are great because they can be a couch or a bed. Here is a simple futon design to make your own platform futon frame out of wood.
Step 1 - Layout
Begin with a full sheet of plywood. Lay it out on saw horses and snap a chalk line dividing out a 27x75-inch piece. With the other half, lay out a 21x63-inch piece. This should leave a 21x33-inch piece and a 21x27-inch piece.
Using the 21x27-inch piece, draw a center line creating two, 13.5x21-inch pieces. Begin at one end of your center line and lay out a groove, one inch wide and eleven inches long.
Using the 27x75-inch piece, draw rounded corners on the two corners on the same 75-inch side, using a pencil and a jar lid. Along the opposite 75-inch side, mark the center point, and the points 12-inches from each end.
Repeat this exact layout with the second sheet of plywood. Lay out 4 21-inch long pieces out of the 2x2-inch lumber.
Step 2 - Cut Out
Cut out all the straight cuts with a skill saw and round the corners with a jig saw. Tune up the edges with a file and sand paper. Make multiple passes with the skill saw to create the 1-inch groove.
Step 3 - Assemble the Base
Begin with the two 21x63-inch pieces, and the 21x33-inch pieces of plywood. Using corner butt joints, assemble a frame 21-inches tall, 33-inches wide, and 63-inches long. Secure the corners with the 2x2-inch blocks and screws.
Step 4 - Assemble an X
Use the 21x27-inch pieces. Insert a groove into the other, creating an X with the 2 pieces of plywood. Place the X, face up, in the center of the base. The X should be 21-inches tall.
Step 5 - Assemble the Platform
Create a 54x75-inch platform by screwing the two remaining pieces of plywood together with door hinges. Center the hinges over the center mark and the marks 12-inches in from the edge. Place the platform either flat over the base, or folded with the back leaning against a wall.
This platform futon frame is low cost, light weight and portable. It can be used as a bed or a couch.