Draw two circles on two plywood squares. One square should be 7.5 inches in diameter, while the other 15 inches in diameter. Use a measuring tape to get the exact measurements.
Cut the circles out of the plywood squares with a saw.
Put the circles in a vise one at a time. Apply wood edge banding around the edge of each circle using a clothes iron. Cut the banding with a utility knife when fully applied to the circle.
Place the small circle on a flat surface. This will serve as the base of your turntable. Place the bearing assembly in the center of the circle and attach it with screws.
Rotate the bearing assembly slightly. Make a mark on the wood through the bearing assembly hole.
Drill a 1/2f-inch hole through the mark on the circle.
Rotate the small circle until the hole lines up with one of the holes on the bearing assembly. Insert a screw through the hole. Continue to rotate your base and insert screws until all four have been attached properly.
Measure the location of the screws on the base carefully. Place the large circle on top of the base and mark where the screws are on the large circle. Remove the large circle and drill 1/2-inch holes where the marks are.
Attach the large circle to the base carefully.