The dust floor is at the top of the mill on the fourth floor, directly beneath the cap (the top part that looks like an upside-down boat). This floor helps to prevent dust and dirt from falling on the mill floors below. It’s also the powerhouse of the mill.
The sails outside turned the windshaft inside – a large horizontal shaft. This is attached to the brake wheel (a big vertical wheel), which turned the wallower (a big horizontal wheel), which then turned the main spindle (a big vertical beam) which drove the millstones two floors below.
The bin floor is the floor where the sacks of grain (wheat, barley and oats) were stored in bins (containers) before milling. Today, we still store grain on this floor and use it for demonstrations.
On this floor and throughout the mill there are trap doors for the sack hoist – a clever mechanism that used wind power to pull the sacks of grain up from the ground flour (avoiding the back-breaking work of having to carry them up by hand!)
The stone floor is where the wheat was ground.
The millstones are inside a wooden vat (see photo) and our stones are made of Derbyshire grit. Originally a spout led from the bin floor above into the hopper, a wooden container that fed the grain to the stones below.
There are two stones: the top stone (called the runner stone) would spin round on top of the bottom stone (called the bed stone) which stayed still.
The grain went into the centre of the stones through a hole in the top stone, and was gradually pushed to the outside edges of the stones by the spinning force. As it moved it was ground into flour by the grooves on the inside faces of both stones.
A paddle on the outer edge of the top stone collected the flour and swept it into a hole in the floor.
Traditionally, the meal floor is where the meal (the name for grindings of any grain) was collected. The wheat flour ground by the stones travelled down a spout to this floor to be collected in a sack.
On this floor if you look up you can see the bed stone – the underneath of the bottom stone. You can also see the centrifugal governor made of cast iron which would have controlled the distance between the stones and kept the millstones at a constant speed as the speed of the wind changed.