=The Steam Cylinder= is that part of an engine in which the piston
travels; it also contains the steam and exhaust ports and is one of the
most expensive, as well as essential, parts of an engine. The cylinder
should be made of the best quality of cast iron, and the greatest care
taken in boring it perfectly true and round. It should be counter-bored
at each end to allow the piston in its travel to overlap at the end of
each stroke. Without the counter-bore, a shoulder would be formed at
both ends of the cylinder as it became worn by the piston rings, which
in time would cause a knock or pound at the end of every stroke; the
only remedy being to have the cylinder re-bored.
Special attention should be paid to keeping the cylinder well oiled
with the best quality of cylinder oil to prevent it from being cut by
the piston rings. If allowed to run dry and cut, it will cause no end
of trouble.
The size of cylinder is not always the measure of the power of the
engine. The power depends upon the heating surface of the boiler and
steam pressure; as the piston speed can always be increased, by running
the engine faster, until the maximum evaporating capacity of the boiler
is reached.