So how far back are we likely to go……………..

[NorthernRaider]

Its all a best or worst best guess I think, My own is we could not really get further back than about the 1850s.

So long as we can still make steel and machine it we can make boilers, if we can make boilers we can make trackers, ploughs, and locomotives and steam ships.
that would take us back to around the 1900s etc. And to begin with there is billions of tons of high quality steel and alloys laying around just waiting to be melted down and reused.

it would be the very delicate stuff we would struggle for so no microchips but probably yes to telephones and telegraphs, no to photo voltaics buy yes to solar water heaters, no to plastic disposable needles and syringes but yes to glass ones. No private cars but yes to trains and canal boats.

Like I say a guess is the best I can think of and it will certainly create full employment as all the mass produced disposable automatic manufacturing processes stop and we have to start over from basic but not medieval levels