The casing for the disk is made of two enameled-iron saucers, Fig. 2, bolted together with a thin piece of asbestos between them to make a tight joint. A 3/4-in. hole is cut near the edge of one of the saucers for the exhaust. If it is desired to carry the exhaust beyond the casing, a thin pipe can be inserted 1/4 in. into the hole. Holes are drilled through the pipe on both inside and outside of the casing, and pins inserted, as shown in Fig. 5. Solder is run around the outside pin to keep the steam from escaping. At the lowest point of the saucer or casing a 1/8-in. hole is drilled to run off the water. A wood plug will answer for a stopcock.
If metal dishes, shaped from thick material with a good coating of tin, can be procured, it will be much easier to construct the casing than if enameled ware is used. The holes can be easily drilled and the parts fitted together closely. All seams and surfaces around fittings can be soldered.
Nozzles are made of two stopcocks having a 1/8-in. hole. These are connected to a 3/8-in. supply pipe. The nozzles should be set at an angle of 20 deg. with the face of the disk. The nozzle or stopcock will give better results if the discharge end is filed parallel to the face of the disk when at an angle of 20 deg. There should be a space of 1/16 in. between the nozzle and the blades to allow for sufficient play, Fig. 3.
The bearings are made of 1/4-in. brass and bolted to the casing, as shown, with 1/8-in. machine screws and nuts. Two nuts should be placed on each screw. The pulley is made by sliding a piece of steel pipe on the engine shaft and fastening it with machine screws and nuts as shown in Fig. 6. If the shaft is square, lead should be run into the segments.
The driven shaft should have a long bearing. The pulley on this shaft is made of pieces of wood nailed together, and its circumference cut out with a scroll saw. Flanges are screwed to the pulley and fastened to the shaft as shown in Fig. 7.
The bearings are made of oak blocks lined with heavy tin or sheet iron for the running surface. Motion is transmitted from the engine to the large pulley by a thin but very good leather belt.
A simple and easily constructed telegraph key may be made in the following manner: Procure a piece of sheet brass, about 1/32 in. thick, and cut out a strip 3-1/2 in. long by 3/4 in. wide. Bend as shown in Fig. 1 and drill a hole for the knob in one end and a hole for a screw in the other. Procure a small wood knob and fasten it in place with a small screw. Cut a strip of the same brass 2-3/4 in. long and 5/16 in. wide and bend as shown in Fig. 2. Drill two holes in the feet for screws to fasten it to the base, and one hole in the top part for a machine screw, and solder a small nut on the under side of the metal over the hole.