This type of mill is supported and pivoted on a single stout upright post, so that the whole “buck” or body of the mill is rotated in order that the sails could be faced square into the wind at all times.
The post-mill spread rapidly throughout Western Europe, as far south as the river Loire.
Across the top of the main post is a stout horizontal beam, the ‘crown tree’, which carries the entire weight of the buck and rotates on a gudgeon at the top of the main post.
Access to the buck is by a flight of wooden steps which are hinged and could be lifted clear of the ground. A heavy beam, the ‘tail pole’, projected through the steps, and when the miller wished to turn the buck into the wind he lifted the steps and pushed the tail-pole, thus rotating the buck into the desired position. The steps are then lowered and the tail-pole anchored to a post