You might know that the thickness of steel is measured in terms of gauge, rather than inches or millimeters, but do you know why? And do you know how gauge works?
Standard gauge sizes, typically ranging between 3 and 30, were developed based on the weight of a sheet of a given material. But they don’t actually indicate a specific dimensional value and there isn’t a consistent difference between each gauge measurement. The decimal equivalent between gauge numbers depends on the type of metal, so to ensure your steel drum meets the appropriate thickness and dimensional requirements for its intended use, you must use the right gauge chart for the right steel.
As for why we measure steel in terms of gauge, that takes us back to the 19th century British iron wire industry. At this point in time, there was no universal unit for thickness. The iron wire industry adopted gauge as the unit of measure and, at the time, gauges were measured and described in fractions of an inch numbered based on the process of wire drawing. Craftsmen found the new universal unit to be convenient and so it was adopted and caught on.
The etymology, however, is French, derived from the word ‘jauge,’ which literally means ‘result of measurement.’