I envy those who know how to use (and enjoy) hand crank machines. I have a couple of them but could never warm up to the idea (or the reality) of engaging one hand with the crank and manipulating my work with the other; too often I need both hands to ease, navigate sharp curves or other fine work. I do like the idea of human-powered machines, so I've found pleasure in working on treadles; a Singer 31-15 (the "tailor's" machine) from 1916 is now my go-to.