Earnshaw set up a business, Reilax Engineering, which specialised in production-line problems.
He invented a number of machines for filling metal and glass containers for the food, cosmetics, chemical and pharmaceutical manufacturing industries.
His oil-free compressor was widely used on tractors, graders, road rollers and similar earthmoving equipment.
Earnshaw's spare time was filled with research into forgotten aspects of Australian history, uncovering new information about the Scottish Martyrs,[3] judge-advocate David Collins, early Sydney cabinetmakers,[4] and John George Lang – the first Australian short story writer.
Thomas Muir: Scottish martyr [Studies in Australian and Pacific History, no 1 (W. W. Stone, editor)].