=The Crank= is that part of an engine by which the effect of the steam
acting against the piston is converted into work. There are two kinds,
Side and Center crank. The term Side crank refers to a disc plate or
a crank attached to one end of a shaft and in which is placed the
crank-pin. When the shaft extends to the right the engine is called a
right hand engine, and when it extends to the left it is called a left
hand engine.
The term Center crank refers to a shaft with the crank in the center,
the shaft extending equally both ways and so constructed as to be very
well balanced. It is optional as to which gives the best results as
both kinds are used upon all sizes of engines.