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Pitstone Green Windmill
Pitstone Green, Ivinghoe, Buckinghamshire, UK
Pitstone Green Windmill
associated engineer
Not known
date  1627, 1749
UK era  Stuart  |  category  Windmill  |  reference  SP944157
ICE reference number  HEW 1768
photo  © Ashley Dace (cc-by-sa/2.0)
Pitstone Green Windmill, sometimes known as Ivinghoe Windmill, is the oldest dated post mill in England. The timber structure is not typical of early post mills as it has a roundhouse, thought to be a later addition. Now extensively restored, the Grade II* listed mill is not in operation but is open to the public.
Pitstone Green Windmill is situated part way up the scarp of the Chiltern Hills above the Vale of Aylesbury. It stands on a small plateau between the upper and lower Icknield ways, with the ground rising behind it for about another 90m. The mill was used to grind locally-grown grain for flour and animal feed.
The first records of a windmill here are dated 1624-8, and held in the Buckinghamshire Record Office. The documents cite tenants of the "Windmill at Ivinghoe" and payments to carpenters working on a pre-existing structure, described as "old". The date 1627 is carved on a lower side timber beam inside the windmill, though dendrochronology (tree ring dating) shows some of the framing timbers were felled between 1590 and 1597. It is also possible the timbers could have been recycled from an earlier building.
The mill consists of a black-painted buck, or body, with a curved gabled roof. The timber frame is clad in horizontal timber weatherboards. Access to the interior is via double doors above a rear step ladder. A small door in the gable opens into the loft, or breast, of the building and was used to reach and maintain the machinery.
The buck is fitted with four 8.2m long anticlockwise common sails, mounted on the opposite side of the body to the doors. The sails are carried on two perpendicular stocks passing through the poll end, a cast iron shoe at the end of the windshaft. As the sails catch the wind, they rotate the windshaft and, through the gear wheels, turn the millstones. The mill does not have a fantail and is luffed by a timber tailpole and wheel, exiting the structure at the top of the ladder.
The buck sits on a 6.7m diameter roundhouse of yellow brick (now whitewashed) with a conical roof of metal sheets and four doorways, originally left open. It protects the mill’s post and trestle, which were open to the weather until the roundhouse was constructed.
Having a roundhouse makes this windmill a 'turret' post mill. Another date carved into its timbers is 1749, presumably added at the time of a rebuilding or perhaps when the roundhouse was added. However, the state of the timbers would indicate that the roundhouse is a later addition, probably 19th century. A date of 1895 low on the wall of the roundhouse may refer to its construction date.
The most important element of the mill is its massive central post, which takes all the load. It is 5.2m long, 838mm in diameter at the base and cut from a single tree, probably felled in the spring of 1597. The crown tree, a large horizontal timber at the top of the main post, transfers the full weight of the buck to the main post and acts as a bearing, allowing the buck to rotate to face the wind.
Below the main post are large horizontal cross trees, or timber beams. The main post does not rest on the cross trees — its base sits about 25mm above them — but is supported on four quarter bars: large diagonally inclined timber braces mounted on piers inside the roundhouse. The cross trees and their iron strapping prevent the weight of the mill spreading the quarter bars. Thus the quarter bars are in compression and the cross trees in tension.
The buck has two floors. The lower level contains the spur wheel and the governor drive mechanism, the meal spouts and bins, and a staircase to the loft. The upper level houses the millstones, brake wheel, brake lever, wallower (horizontal gear driven by the brake wheel), windshaft, breast beam and sack hoist. The hoist is driven by a chain from the windshaft.
The millstones are 1.2m in diameter, under driven by the spur wheel — one pair of coarse Peak stones and one pair of French Burr stones. A single governor controls both pairs. Hoppers above the stones fed them with grain. Milled wholemeal was graded into white flour, middlings and bran as it passed through a series of wire meshes, before being directed into the meal bins on the lower floor.
The heaviest machinery is original, and the other machinery is from other mills. The windshaft and brake wheel are of timber, other gearing is made of iron.
The earliest person known to be connected with the mill was John Burt. In 1770, he owned the windmill and Ford End Watermill (SP940165) to the north north west. They passed to his son James Burt in 1786, and were sold at auction in 1810, probably to the Grand Junction Canal Company. In 1823, the miller is listed as Benjamin Anstee.
In 1842, the Grand Junction Canal Company sold the mill to Francis Beesley who worked it for 32 years. In 1874, Beesley sold the mill for £400 to Adelbert Wellington Brownlow-Cust (1844-1921, 3rd Earl Brownlow), owner of Ashridge Estate. Lord Brownlow let it to the Hawkins family, tenant farmers of Pitstone Green Farm, who employed Jim Horn as miller. Horn worked the mill until around 1894, followed by Charles Simmons.
In 1894-5, major repairs were carried out including the reboarding of the buck. In 1902, the mill was badly damaged when a squall caught the sails before they could be turned to the wind. The gale unseated the windshaft from its tail bearing, the bearing crashed through the roof, the sails collided with the roundhouse walls and two sails were blown away.
In 1924, the Hawkins family bought the mill. Repairs proved too expensive and the mill fell into disrepair. In 1937, the family gave the building to the National Trust. Some conservation work was done to prevent further deterioration, and two of the roundhouse’s four doorways were bricked up. In 1938, one of the remaining doorways was fitted with "a beautiful iron-studded oak door".
In September 1951, the mill was Grade II* listed (listing amended October 1984). In 1954, an inspection by mill historian Stanley Harman Freese (1902-72) revealed the main post was not vertical, owing to decay in the quarter bars. Two 4.9m pitch pine baulk timbers were used to support the main post temporarily, tenoned into the 'dummy’ erection mortises of the post and wedged against timber plates at the base of the roundhouse wall. Freese recommended the baulks be replaced in oak as a permanent solution.
It was not until 1963, and the formation of the Pitstone Mill reconstruction committee, that the building was restored to operational condition. Funds to pay for materials were raised from donations and grants, labour was provided by volunteers. In 1970, the mill once again ground grain.
The National Trust now maintains Pitstone Green Windmill as a non-working exhibit. Though the mill is capable of grinding flour, the sails cause too much shaking for it to be undertaken safely (perhaps the main post is still not quite vertical). The building is kept in good repair by annual maintenance.
Research: ECPK
"Gone with the Wind: Windmills, and those around Tring" by Ian Petticrew and Wendy Austin, ebook at tringlocalhistory.org.uk, Tring, 2010
reference sources   CEH E&C

Pitstone Green Windmill