No.1810
It depends on your definition of «tech». If you mean computer tech, I read old 1987 magazine which had printouts of their own OS CP/M rip-off in hexadecimal format. Readers were supposed to solder their own chip programmator (there was schematic), then input a few pages of hex. That seemed pretty hardcore for me.
If you mean tech in general, I read early XX century book of household «hacks» - how to drill window glass, anneal glassware, treat wood, make paints and so on.