page_title: Upminster Windmill
section_title: Machinery
hierarchical_section_title: Upminster Windmill / Description / Machinery
caption_attribution_description: English: The compass arm Great Spur Wheel, Upminster Windmill.
context_page_description: Upminster Windmill is a Grade II* listed smock mill located in Upminster in the London Borough of Havering, England. It was formerly known as Abraham's Mill and was in Essex when built. It has been restored and is a museum open to the public at selected times.
context_section_description: The Upright Shaft is wooden, in two sections for reasons noted above. It is twelve sided, 18 inches (460 mm) across the flats and 30 feet 4 inches (9.25 m) long in total. The Wallower is of compass arm construction, 5 feet 4 inches (1.63 m) diameter with 43 cogs. At the bottom of the Upright shaft the 10 feet (3.05 m) diameter compass arm Great Spur Wheel has 126 cogs. It drives four pairs of underdrift millstones via stone nuts with 24 cogs.
  The millstones are three pairs of French Burr stones and one pair of Peak stones. Two pairs of the French Burr stones are 4 feet 6 inches (1.37 m) diameter and the other two pairs of millstones are 4 feet (1.22 m) diameter.
caption: The Compass Arm Great Spur Wheel
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