[varjag]

Look, I have a lathe at home and can make an engine if I want to, thing is other people can't because they never were interested in that. And I used the simplest things possible as examples.

Realistically, where would you start with these in a typical deindustrialized town today? "A factory" is a poor answer, some towns have none really, and factories are not interchangeable anyway.

[rwmj]

There are small factories - everything from workshops to industrial estates - all over the place. If anything it's much better now because CNC machines and lathes are cheap, widely available and very versatile.

[throwanem]

Yes, they're cheap and widely available. That's because we import them from China.

If your plan for resilience against a long-term disruption of global trade has a critical dependency on global trade, you may need to rethink it somewhat.