How did C.H. Norton's grinding machine reduce the time needed to grind an automobile crankshaft?

C.H. Norton of Massachusetts demonstrated the significant potential of grinding machines by developing a model capable of grinding an automobile crankshaft in just 15 minutes. This represented a dramatic improvement in efficiency, as the same process had previously required five hours to complete.1

This advancement was made possible by the late 19th-century production of artificial abrasives, which opened a new field of machine tool technology. By utilizing these abrasive systems, manufacturers could achieve high rates of production, maintain tight dimensional tolerances, and process materials that were otherwise too hard to be machined by conventional cutting tools.12