Before making the tank it is most desirable to assemble the parts of the engine, and this may be done by first fitting the pistons into the cylinders as shown inFigure 1-b, after which the cylinders should be lapped one over the other and soldered as shown inFigure 1-a. When this has been done a hole one-fourth of an inch in diameter should be drilled half way between the ends of the cylinders, and into this hole should be soldered one end of the valve casing shown inFigure 4. For the inlet pipes as shown inFigure 1-csecure two pieces of ¹⁄₈″ brass tubing and after heating until soft,bend both to a shape similar to that shown inFigure 1-c. When this has been done solder one end to the end of the cylinder and the other in the second hole of the valve shaft casing. The valve shaft should now be inserted in the valve shaft casing and the connecting rods sprung onto the crank throw as shown inFigure 1-d. To loosen up the parts of the engine which have just been assembled it should be filled with oil and by tightly holding the crankshaft in the jaws of a drill the engine can be worked for a few minutes.
The tank is made from a sheet of brass or copper foil 15″ long by ¹⁄₁₀₀₀″ thick. This is made in the form of a cylinder, the edges of which are soldered together as shown inFigure 2. Sometimes this seam is riveted every one-half inch to increase its strength, but in most cases solder is all that is required to hold the edges together. For the caps, or ends, the tops of two small oil cans are used, each can measuring 2¹⁄₂″ in diameter. To complete the caps two discs of metal should besoldered over the ends of the cans where formerly the spouts were inserted, the bottoms of the cans having been removed. The bottom edges of the cans should be soldered to the ends of the tank as shown inFigure 2. Into one end of the completed tank a hole large enough to receive an ordinary bicycle air valve should be drilled.Figure 2. Another hole is drilled into the other end of the tank, into which is soldered a small gas cock to act as a valve.Figure 2. This should be filed down where necessary, to eliminate unnecessary weight. To connect the tank with the engine, a piece of ¹⁄₈″ brass tubing 3″ long is required, the ends of which are soldered into the holes in the valve shaft casing nearest the cylinders, as shown inFigure 1-ee. As shown inFigure 1-ee, a hole ¹⁄₈″ in diameter is drilled in one side of this piece, but not through, in the end nearest the tank. Another piece of brass tubing ¹⁄₈″ in diameter is required to connect the tank with the engine, one end of which is soldered to the cock in the tank, the other in the hole in thepipe which leads from the engine to the tank, illustrated inFigure 1-ee, thus completing the engine.
In conclusion it is suggested that the builder exercise careful judgment in both the making and assembling of the different parts of the engine in order to avoid unnecessary trouble and secure satisfactory results. After having constructed an engine as has just been described, the constructor may find it to his desire to construct a different type of engine for experimental purposes. The constructor therefore may find the descriptions of satisfactory compressed air engines in the following paragraphs of suggestive value.