Avoncroft’s much-loved windmill is a typical west midlands post mill: the entire upper structure, called the buck, pivots on a huge central post. This means that it can be turned around so that its sails always face into the wind and generate the maximum possible power. Each pair of sails has an18m-wide span and is attached to the windshaft. As this rotates it powers a giant cog wheel that turns the millstones inside the mill. The windshaft also powers a winding mechanism to help workers lift the bags of grain to the top of the mill (through trap doors) so they could feed it between the grinding stones to make flour.