Millstone - Wikipedia
The runner stone is supported by the rind, a cross-shaped metal piece, on the spindle.The spindle is carried by the tentering gear, a set of beams forming a lever system, or a screw jack, with which the runner stone can be lifted or lowered slightly and the gap between the stones adjusted. The weight of the runner stone is significant (up to 1,500 kilograms (3,300 lb)) and it is this weight ...