To build a wobble board, first decide on the shape of the base (square, round or clover-leaf). The square base is 18” on any side; the round base has a diameter of 2 feet. The clover-leaf base is made of overlapping circles whose centers are the corners of an 18” square. Cut the base out of 3/4” plywood. Sand all surfaces well, and sand or route all edges.
Next, cut the 4 rockers from 2” thick hard wood. Pine was used in this design. The rockers are 12” in length, flat on one side and rounded on the other, with a maximum depth of 3.5”. Carefully sand all surfaces, with special attention to the rocker surface, which
must be smooth if the wobble board is to operate smoothly.
Use a pencil, measuring tape and t-square as needed to locate the center point of the underside of the base. Draw a circle centered at this point with a diameter of 12”. The rockers will be mounted into this circle. Glue one rocker in place. Use a miter saw to remove the center 2” of the remaining rockers. Glue both sides of a second rocker to the base, forming an axis perpendicular to the first.
Use a miter saw to create 45 degree angles on the remaining rockers (two with “positive” angles, and two with “negative” angles). Glue the remaining rocks in place.. Weight and allow to fully dry.
Once the glue is dry, turn the wobble board upright and use a drill to screw a wood screw into each rocker. Make certain each screw is countersunk into the base. Sand the rockers again, if needed for smooth operation. Apply wood filler to the screw holes and allow to dry. Sand.
Paint with primer and at least two coats of non-toxic acrylic paint, sanding between coats.