Cutting Millstones in Loranger Gristmill in Preparation for Summer, Greenfield Village, 1981

Gristmills use a pair of millstones to grind grain. An evenly balanced top stone, or runner stone, spins above a stationary bedstone. A precise pattern of grooves cut into both stones creates a scissoring action, shearing grain, channeling it across uncut grinding surfaces, and carrying it out from the stones. Millstones must be periodically dressed, or recut, to keep them clean and sharp.