It utilizes the cylinder bores and engine deck to provide accurate surfaces.

This required the cylinder bore to be wider in the cool centre than at the hot ends.

They had 1 -inch exhaust valves, which required the cylinder bores to be notched for clearance.

Watt tried having cylinders bored from cast iron, but they were too out of round.

The cylinders bore rings of smaller tubes at one end while the other was blunt-nosed.

A second smaller cylinder bored a plug from the rock, and worked on it.

An exception is in cylinder bores where oil is retained in the surface profile and a minimum roughness is required.

In May 1951, five locomotives had liners fitted to their cylinders to reduce the cylinder bore from 20 in to 18 in.

It was the first "over-square" engine - with a cylinder bore greater than its stroke - that the manufacturer installed in a production car.

The cylinders could not be bored out further so the stroke was lengthened from 72.8mm to 79.3mm, resulting in a capacity of 646cc.