Next the shaft in Fig. 346 is made. K P is the same length as G H in Fig. 345 and about ¼ inch by ¼ inch; K M, L N, O J, P U are each 4¼ inches long, they are the same distances apart as C G, Q R, S T and E H in Fig. 345. They are held together by strips, V, W, X, Y, Z. These strips may be matches; in this case they must be inserted first, and then the whole of K M P U is glued to K P.
Fig. 345
Figs. 346 and 347
This shaft is fastened to the main ladder in Fig. 345 midway between A B and G H, so that when the shaft is horizontal the main ladder makes an angle of 72° with it.
Fig. 347 shows the shaft M K, P U, attached to the main ladder; it is supported in its place by four struts, two on each side (a and b in Fig. 347). Care must be taken to saw off the ends M, N, J, U (Fig. 346) so that they rest exactly against C D, R Q, S T, E F (Fig. 345), at about an angle of 72°. The ends of the struts must also be carefully bevelled to fit; the main ladder can then be glued to the shaft and the struts to the main ladder and shaft.
Small wheels of cardboard or wood are nailed (as for ship's cannon) at each end of G H.
An axle for the larger wheels must be made to be glued on K P (Fig. 347). Care must be taken in deciding on the size of the large wheels, the diameter must be such a length that the shaft, K M P U, is parallel to the ground.