cylinder-end cover can then be placed inside the cylinder, and the
piston-end cover is soldered in place. Before final assembling the
piston should be made to fit nicely into the cylinder. This can be
brought about by applying emery cloth to the piston-head until it slips
nicely into the cylinder with little or no play. Thus a steam-tight fit
is made, and this contributes greatly to the efficiency and power of the
engine.

[Illustration: FIG. 56]

[Illustration: FIG. 57]

The cylinder blocks are shown in Fig. 55. These are cut and brought to
shape with a hacksaw and file. With a half-round file one side of one of
the blocks is filed slightly concave, so that it will fit on the outside
of the cylinder. Two 1/8-inch holes are drilled in this piece as shown
in the drawing. The hole at the top is the steam entrance and exhaust
for the engine; that is, when the cylinder is at one side steam enters
this hole, and when the crank throws the cylinder over to the other side
steam leaves through the same hole after having expanded in the
cylinder. This cylinder block is soldered to the piston as shown in
Fig. 56. The pivot upon which the cylinder swings is then put in place
in the hole at the bottom of the block. Solder is flowed around the
pivot to hold it securely in place.

The second cylinder block is now finished according to the drawing. This
has two holes 1/8 inch in diameter bored in it. One of these holes is
the steam inlet and the other the exhaust. When the cylinder is at one
side of its stroke the hole that was bored in the top of the steam block
which was soldered on the cylinder is in line with the inlet hole in the
block under consideration. Steam then enters the cylinder and forces the
piston down. This turns the crank around, and the crank in turn pulls
the piston over to the opposite side, so that the hole in the first
piston block of the cylinder now comes in line with the exhaust hole on
the second cylinder block. The steam in the cylinder escapes and the
same operation is repeated over again. Of course, it must be understood
that this steam admission and exhaust takes place very rapidly. The hole
in the second cylinder block, which goes over the pivot, must be made a
trifle more than 1/8 inch in diameter, so that it will slide freely over
the pivot.

The engine is mounted on a very simple frame, which is a piece of
1/16-inch brass cut and bent as illustrated. After it is cut and bent to
shape the secon