Earlier this week, adjustable props were inserted on the ground and first floor of the mill to take up the weight of the main millstones on the second floor. This meant that the jib for lifting the provender millstones could be freed.
The upper runner stone (the one that actually turns) was removed, leaving the lower, stationary bedstone in place. Now that the stones are separated, you can see the grooves in the runner stone that provide a cutting edge, and how the bedstone is made up of different sections of quartz bound together with plaster of Paris.
On top of the runner stone is the name of the ‘millstone builder’, Bryan Corcoran (see photo, left). This advert from 1878 shows that the price of French stones was at least twice as much as Derbyshire Peak stones.