Next we sawed out the wheels of our car. From a board of hardwood 3/4 of an inch thick four disks, 12 inches in diameter, were sawed out. Then from a board 1 inch thick four 9-inch disks were sawed out. We cut these disks in the same way as we had made the disks for our surveying rod (see page 78), by making cuts across corners and finally smoothing off the angles with a draw-knife. A half-inch hole was now drilled in the center of each disk. Then on each large disk a smaller one was placed, with the center holes of the two coinciding and the grain of one lying across the grain of the other. In this position they were firmly nailed together, making a wheel like those used on a railway car, with the small disc forming the tread of the wheel and the large disk serving as a flange.