Convert from microinch to ridge

Unit Definition (microinch)
The microinch is a common imperial unit of distance equal to one millionth of an inch, or 25.4 nanometers (nm). The microinch is used for precise machining tolerances and also to describe the roughness of surfaces.

Unit Definition (ridge)
The ridge is a traditional Welsh unit of distance equal to 3 leaps or 20 feet 3 inches (6.1722 meters).