Dressing the Millstones
Dressing the Millstones refers to the work required to ensure the milling surface is as near flat as possible. It is required because with use the Millstones wear away and due to different densities in the rock this wear isn't even. Every so often the miller would be required to remove a set of stones from use to take off the Stone Case and Grain feed and pull the stones apart.
The stones were lifted apart using a wood wedge to separate the two stone then a block and tackle was used to lift them apart. Once the two stones were laid flat with the milling surface uppermost the miller would take a proof staff (which was a piece of wood or metal with a flat surface) and lay in on the stone. This would identify any bumps.
The miller would than take a tool called a Thrift and use it to chip away at the raise portion of the stone. The Thrift is a specialised pick consisting of a wooden handle into which a doubled ended metal blade (called a Mill Bill) is placed. This tool was used in a tapping motion to flatten the stone surface and re-cut the groves in the stone. The picture above shows two of the original Thrifts used in Wheatley mill.