[Illustration: Cross-head.]
=The Cross-head= is of cast iron and connects the piston rod to the
connecting rod, and is that part of an engine where the motion is
changed from vibrating to rotary. The piston rod is fastened securely
to it, while the connecting rod is attached by wrist-pin. On a V guide
or bored guide engine frame the cross-head is supplied with adjustable
shoe slides that can be adjusted to take up their wear and fit the
guides properly, also to keep the piston rod in line. On a bar or
locomotive guide engine the cross-head is adjusted by removing the
liners from between the bars.