In this way you may continue to saw off the triangular corners until you reduce the wheel to a condition where it only needs the application of a sharp knife to round the edge until it corresponds with the pencil circle. [Illustration: FIGS. 123-126.--The Wheel.] What is called The Flange of the wheel is practically another wheel, made of thinner material (Fig. 124), which is securely nailed to the first wheel (Figs. 125 and 126), with the grain of the wood of the flange crossing the grain of the wood of the wheel proper at right angles. The flange is made of one-inch board, and to prevent its splitting is reënforced by a strip of wood fastened on across the grain, with screws, as shown in Fig. 124. When the four wheels are finished, and a hole large enough for a good strong axle is bored in the exact centre of each, you will be ready to begin work upon the car. Set the Car-Bed Low. The smallest boy will understand that the lower the bed of the car is put the less the danger of an upset, so instead of putting the axle, under the car, run them through the bed, as shown by Fig. 128. [Illustration: FIGS. 127 and 128.] Build the Axles of four-by-four timber, and by the aid of a drawing-knife or a good, strong, sharp jack-knife, trim off the ends of the timber to the form shown in the diagram. When the ends are small enough to allow the wheels to revolve freely, saw out places in the side-boards of the car (Figs. 127 and 128), into which the square part of the axle will snugly fit. The Bottom of the Car may be made of half-inch boards, which can be joined and nailed on to the car, with their irregular ends protruding, after which, with a hand-saw, cut off the ends even with the side-boards, as in Fig. 129. Then nail in place the head and tail-boards, and in the same manner saw off their protruding ends, even with the side-boards (Fig. 129). To finish your car it is only necessary to slip the wheels upon the axles. The wheels may be held in place by pegs of hard-wood driven through holes in the hub, made for that purpose, as shown in Fig. 130. You will then have a car, but no track to run it upon. However, if you build the toboggan slide which is described in the next chapter, you may lay rails, made of two-by-four timber, down your toboggan slide and thus transform it into a back-yard “switchback.” [Illustration: FIG. 129 and 130.] But if you have no toboggan slide you will have to build a tramway for your car against the back fence, wood-shed, or any other suitable place. In the diagram (Fig. 135) here given, the slide is shown as it would be if built against the back fence, extending forward through the middle of the yard. But you must have a Starting Platform.