Fig. 5.
The next step is to cut out the side frames ([Fig. 4]), drilling holes at A B C for the axles to work in; you can finish both sides in the same way, and, turning the bed-plate upside down, fasten the frames on at a quarter of an inch from either side by small angle pieces, as in [Fig. 5], or by soldering, which is much quicker. Then fasten by the same means a piece across each end about half an inch deep, and the frame is ready for the wheels.
Fig. 6.
These can be had ready finished, but if you have the castings, they must be chucked in the lathe and the tires turned up to the form shown in [Fig. 6]. The small wheels should be about two and a half inches diameter and the driving wheels four inches. The rim B should project a little over one-sixteenth of an inch, and the rest of the edge should be bevelled off slightly as at A.
The spokes may then be filed up smooth, previously drilling out the centre hole for axle before removing it from the lathe.
Fig. 7.
Great care must be taken to turn both the driving-wheels to exactly the same diameter, or one wheel would travel farther in a revolution than the other, and as they ought to be both fixed rigidly on to the crank shaft, the engine would never travel in a straight line, but would always run in a circle. You will require some steel wire for the axles, and can fasten them to the wheels by soldering or by cutting a slot with a fine file in the centre of wheel, as at A, [Fig. 7]; then filing a small portion of the ends of the axle flat, drive in a brass wedge made from a piece of wire, which will hold them together firmly.
The crank shaft or axle must be hammered up to shape, making it hot occasionally in the gas flame whilst working it.