ieces found in a scrap
pile that usually occupies a fence corner on almost every farm.
The cylinder consists of

[Illustration: Complete Homemade Gasoline Engine]

an old pump cylinder, 3/8 in. thick, 1-3/4 in. inside diameter and
about 5 in. long. This was fastened between some wooden blocks
which were bolted on the tool carriage of a lathe and then bored
out to a diameter of about 2 in. The boring bar, Fig. 1, consisted
of an old shaft with a hole bored through the center and a tool
inserted and held for each cut by a setscrew. A wood mandrel with
a metal shaft to turn in the centers of a lathe was made to fit
the bored-out cylinder. The cylinder was then placed on the
mandrel, fastened with a pin, and threaded on both ends. Flanges
were next made from couplings discarded from an old horsepower
tumbling rod, to fit on the threaded ends of the cylinder casting.
When these flanges were tightly screwed on the casting and faced
off smooth the whole presented the appearance of a large spool.

The back cylinder head was made from a piece of cast iron, about
1/2 in. thick, turned to the same diameter as the flanges, and
with a small projection to fit snugly inside the cylinder bore.
Two holes were then drilled in this head and tapped for 3/4-in.
pipe. Two pieces of 3/4 -in. pipe were fitted to these holes so
that, when they were turned in, a small part of the end of each
pipe projected on the inside of the cylinder head. These pieces of
pipe serve as valve cages and are reamed out on the inside ends to
form a valve seat. The outlet for the exhaust and the inlet for
the gas and air are through holes drilled in the side of each pipe
respectively and tapped for 1/2-in. pipe. Two heads were then made
to fit over the outer ends of the valve cages. These heads looked
similar to a thread spool with one flange cut off, the remaining
flange fitting on the

[Illustration: Steps in Making the Home-Made Gasoline Engine]

end of the valve cage and the center extending down inside to make
a long guide for the valve stems. These heads are held in place by
a wrought-iron plate and two bolts, one of which is plainly shown
in the picture. This plate also supports the rocker arms, Fig. 2,
and the guides for the rods that operate the valves. Both valves
are mechanically operated by one cam attached to a shaft running
one turn to two of the crankshaft. The gears to run this shaft
were cut from solid pieces on a small home-made gear-cuttin