God forbid, but if there ever was a technology reset (nuclear, EMP, etc.), those of us who survive will really be dependent on those who were old enough to know, or those who were lucky enough to have been taught, those 19th and early 20th century skills.
I have no fine woodworking skills, but was lucky enough to grow up in a family of people who work with metal - machinists, fabricators and such. I picked up much of that. Comes in handy with firearms, too. If I can't find a part, I can usually make it - even without a computer controlling the process. Slow, but in a post-Apocalyptic world, slow will be the norm.
I think of my grandfather's shop equipment back in the Depression. Everything, including his metal lathe and vertical mill, ran on batteries charged by wind power. The small windmill was connected to an automotive generator which charged a group of 12 volt batteries that supplied the power. Also supplied lighting to work at night. Fitting, of course, was done entirely by hand.