The ports were not easy to make, as

[Illustration:  The Engine Is About 20 Inches High]

they had to be drilled and chipped out.  The steam chest is round, as it had to be made to fit the round tee connection.  The crosshead runs in guides made from a piece of gas pipe with the sides cut out and threads cut on both ends.  One end is screwed into a rim turned on the cylinder head and the other is fitted into an oblong plate.  Both ends of this plate were drilled and tapped to receive 1-1/2-in. pipe.

The main frame consists of one 1-1/2in. pipe 10 in. long and one made up from two pieces of pipe and a cross to make the whole length 10 in.  These pipes were then screwed into pipe flanges that served as a base.  The open part of the cross was babbitted to receive the main shaft.  The end of the shaft has a pillow block to take a part of the strain from the main bearing.  The eccentric is constructed of washers.  While this engine does not give much power, it is easily built, inexpensive, and anyone with a little mechanical ability can make one by closely following out the construction as shown in the illustration.  —­Contributed by W. H. Kutscher, Springfield, Ill.

** How to Make a Copper Bowl [185]

To make a copper bowl, such as is shown in the illustration, secure a piece of No. 21 gauge sheet copper of a size sufficient to make a circular disk 6-1/2 in. in diameter.

Cut the copper to the circular form and size just mentioned, and file the edge so that it will be smooth and free from sharp places.  With a pencil compass put on a series of concentric rings about 1/2 in. apart.  These are to aid the eye in beating the bowl to form.

The tools are simple and can be made easily.  First make a round-nosed mallet of some hard wood, which should have a diameter of about 1-1/4 in, across the head.  If nothing better is at hand, saw off a section of a broom handle, round one end and insert a handle into a hole bored in its middle.  Next take a block of wood, about 3 by 3 by 6 in., and make in one end a hollow, about 2 in. across and 1/2 in. deep.  Fasten the block solidly, as in a vise, and while holding the copper on the hollowed end of the block, beat with the mallet along the concentric rings.

Begin at the center and work along the rings—­giving the copper a circular movement as the beating proceeds—­out toward the rim.  Continue the circular movement and work from the rim back toward the center.  This operation is to be continued until the bowl has the shape desired, when the bottom is flattened by placing the bowl, bottom side up, on a flat surface and beating the raised part flat.  Beating copper tends to harden it and, if continued too long without proper treatment, will cause the metal to break.  To overcome this hardness, heat the copper over a bed of coals or a Bunsen burner to a good heat.  This process is called annealing, as it softens the metal.