that is a nice picture of a burr stone's segments, and the steel band that held everything together--thanks for taking the time to post it here, for everyone to see
it is hard to explain the texture of the stone but when it is furrowed and trued, it produced the finest of flour, of course you needed a top notch miller to utilize the operate the mill--needless to say--my father used to say--"you can have the best tools, but if you can't use them properly, the outcome is for naught"
Getting back to the second part of your question concerning the suspension of the rotating upper stone and maintaining its tolerances--this is how that was achieved-----
you have to visualize the setup, the grinding stones sit atop a husking frame, which is a network of timbers, which sits within the mill structure, and is independent of the mill's structure--which means it cannot touch any part of the mill itself, this is important because the vibration of the grinding stones at work would eventually destruct the structure
This husking frame in a mill using a turbine would sit astride the turbine in the basement, with it right in the centre of the framework, and rising from the turbine would be the driveshaft, usually about 4" in diameter, this shafting would rise from floor to floor right up into the attic, and at this point would with the help of bevel gearing redirect the shaft's rotation horizontally usually right across the total attic area
it is up in here that many wooden pulleys of varying sizes would be rotating sending down power to the various floor's equipment using leather belting also of varying widths, depending on the amount of power being expended from the shafting, and of course needed
also up in here would be situated the sack hoisting equipment, a very crude but also very workable and necessary setup---needed to quickly move bags of grain to the top story beginning its eventual movement downwards towards the grinding stones