[jasonwatkinspdx]

Once they got going, liberty ships took an average of like 40 days. As a stunt they built one in 5 days.

The scale of WW2 manufacturing boggles the mind. The numbers from Russian tank factories are pretty astounding too.

[astrodust]

All of that with virtually no automation as well. Just sheer brute force of labour: Machinists, welders, forge operators and their tools.

[flukus]

Kind of depends on your definition of automation, I suspect many of those jobs were using much more advanced tools than their grandparents would have. If I were to build a fence tomorrow I'd be using a nail gun and bench saw to automate most of the hard work, as little as a few decades ago I wouldn't have had those tools.