Millstone

For other uses, see Millstone (disambiguation).
"Grinding stone" redirects here. For the metalworking tools, see grindstone and grinding wheel. For the album by the Gary Moore Band, see Grinding Stone (album).
This article is about stones used to grind grains. For roadside distance markers, see Milestone.

The basic anatomy of a millstone. This is a runner stone; a bedstone would not have the "Spanish Cross" into which the supporting millrind fits.

Millstones or mill stones are stones used in gristmills, used for triturating, crushing or, more specifically, grinding wheat or other grains. They are sometimes referred to as grindstones or grinding stones.

Millstones come in pairs: a stationary base with a convex rim known as the bedstone[1] (or nether millstone)[2] and a concave-rimmed runner stone[3] that rotates. The movement of the runner on top of the bedstone creates a "scissoring" action that grinds grain trapped between the stones. Millstones are constructed so that their shape and configuration help to channel ground flour to the outer edges of the mechanism for collection.

The runner stone is supported by a cross-shaped metal piece (millrind or rynd) fixed to a "mace head" topping the main shaft or spindle leading to the driving mechanism of the mill (wind, water (including tide), or other means).

  1. ^ "bed-stone". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
  2. ^ Emblematic of hardness in (for example) Job 41:24 - "His heart is as firm as a stone; yea, as hard as a piece of the nether millstone."
  3. ^ "cock-eye". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)