[["The weight of the runner stone is significant (up to 1,500 kilograms (3,300 lb)) and it is this weight combined with the cutting action from the porous stone and the patterning that causes the milling process. Millstones for some water-powered mills (such as Peirce Mill) spin at about 125 rpm.", 27.0], ["2.205 poundstones. ", 7.0]]
how much does a millstone weigh
animals