Stone mill, also called rolling mill, is a kind of agricultural tool used to grind wheat. Most of them are carved from bluestone, which is half a foot long and about a foot in diameter, and varies in size. It stands like a frustum, with long ribs around it, two flat ends, and a round belly button in the center of the plane. The stone mill must have a roller frame and a stone pull.
The roller frame is a wooden frame with upturned ends to enclose the stone roller. The stone grate is a triangular stone with a round hole on its side. Its function is friction, which makes it easier to separate the wheat grains squeezed by the stone mill from the wheat ears (photo source: Siyuan Garden, No.58 Middle School, Zhengzhou City).