How London's Crystal Palace was built quickly (2024)
arstechnica.com
arstechnica.com
Whitworth sizing made no sense. Only decades later did I realise that Whitworth is a measurement of the bolt diameter, while the distance across the flats of the bolt heads and nuts were some standardised mathematical multiple of that; and that AF wasn't an acronym for "American Fine" it was simply "across flats" which made finding the spanner to match the bolt much, much easier.