d cylinder block is soldered in place. The cylinder can
then be mounted. It will be seen that the pivot goes through both the
second cylinder block and the engine standard. A small spring is placed
over the protruding end of the pivot and a nut put in place. By turning
this nut the pressure on the face of the two cylinder blocks can be
adjusted, and the model engineer must always remember that the pressure
on these springs must be greater than the steam pressure in the
feed-pipe. Otherwise the steam pressure will force the cylinder-block
faces apart and steam leakage will result. On the other hand, the
pressure of the spring should not be too great, since that would
interfere with the free movement of the engine cylinder.

Nothing now remains to be made except the crank and the flywheel. The
crank revolves in a small brass bearing which is soldered in place on
the engine standard. It will be seen that the sheet brass that makes up
the engine standard is not thick enough to offer a good bearing for the
crank. The crank is bent to shape from a piece of 1/8-inch brass rod,
and the author advises the builder to heat the brass rod red-hot while
the bending is done. This will prevent it from fracturing, and will also
permit a sharp bend to be made.

The flywheel is a circular piece of brass 1 inch in diameter. Its center
is drilled out and it is soldered to the crank as illustrated in Fig.
54. Two other holes 1/8 inch in diameter are drilled in the flywheel as
illustrated, and two small brass pins are cut out from 1/8-inch brass
rod and forced into these holes and then soldered. These provide a
method of driving the propeller-shaft that is shown very clearly at Fig.
57.

The steam feed-pipe that runs from the boiler to the engine can be of
small copper tubing. It may be necessary to mount the engine on a small
block, as shown in Fig. 53. After the steam in the boiler has reached a
sufficient pressure the engine crank should be given a couple of twists
in order to start it. Before operating the engine a little lubricating
oil should be run into the cylinder through the inlet or exhaust ports.
The cylinder should always be kept well lubricated. The contacting faces
of the cylinder blocks should also be kept lubricated.

_Caution._ Always keep water in the boiler. Never permit it to run dry,
as this would cause a boiler explosion. When the engine is started and
cannot be made to run, take the burner from under the boiler so t