Ok, I proved it possible to make polished slabs of substantial size (ca. 50 cm2) without any machine, purely by hand, in an acceptable time and of good quality and with things I already had, especially flat plates. Grinding and polishing media had to be bought, of course. All of this can be done on a desk in an apartment, no serious noise or dust production involved, just some sludge . Only one problem remains - you need an as flat as possible surface to start with. Such flat surfaces are u