page_title: Glossary of mill machinery
section_title: Watermill machinery
hierarchical_section_title: Glossary of mill machinery / Watermill machinery
caption_attribution_description: English: Crown wheel in a watermill at Coleshill, Oxfordshire (formerly Berkshire)
context_page_description: This glossary of mill machinery covers the major pieces of machinery to be found in windmills, watermills and horse mills. It does not cover machinery found in modern factories.
context_section_description: Axle
  The axle carries the waterwheel. It can also carry the Pit Wheel at its opposite end.
  Bedstone
  The Bedstone is the bottom of a pair of millstones. It does not move. The upper stone is called the Runner Stone.
  Crown Wheel
  The Crown Wheel is a driving wheel located at the top of the Upright Shaft
  Great Spur Wheel
  The Great Spur Wheel is a large gear attached to the Upright Shaft. It drives one or more Stone Nuts in a corn mill. If mounted on a Layshaft it is called a Spur Wheel and only drives one Stone Nut
  Hurst Frame
  An internal framework supporting the gears and millstones. This isolation prevents damage to the building from the vibrations of the workings.
  Layshaft
  A Layshaft in a watermill is a horizontal shaft, carrying a Wallower and one or more Spur Wheels. The term can also refer to a minor shaft driving machinery by pulleys and belts.
  Overdrift
  Millstones driven from above are known as Overdrift stones.
  Pit Wheel
  The Pit Wheel is mounted on the opposite end of the axle to the waterwheel. It drives the Wallower on the Upright Shaft or Layshaft.
  Rim Drive
  Some waterwheels have a rack attached to the circumference, which drives the mill via a pinion mounted on a separate axle, which has a Pit Wheel at its opposite end. This is known as Rim Drive.
  Runner Stone
  The Runner Stone is the topmost of a pair of millstones. It is driven by the Stone Nut. The lower stone is called a Bedstone.
  Stone Nut
  A Stone Nut is a small gear driven by the Great Spur Wheel or Spur Wheel. It drives the Runner Stone. In most watermills, the stones are driven from below. These are called Underdrift stones. A few watermills drove the stones from above, known as Overdrift stones.
  Turbine
  In some watermills, a Turbine was used as a source of power instead of a Waterwheel. In many cases, the Turbine was installed when a watermill was modernised, although a few mills were built new with Turbines.
  Underdrift
  Millstones driven from beneath are known as Underdrift stones.
  Upright Shaft
  The Upright Shaft in the main driven shaft in a watermill. It carries the wallower, Great Spur Wheel and sometimes a Crown Wheel.
  Wallower
  The Wallower is a small gear at the base of the upright shaft in a watermill, it is driven by the Pit Wheel.
  Waterwheel
  A waterwheel is a source of power for a watermill. It is mounted on the axle and drives the mill by a Pit Wheel or Rim Drive. In some watermills, the Waterwheel was replaced by a Turbine.
caption: Crown Wheel and Upright Shaft
exif: {"Image Make": "Panasonic", "Image Model": "DMC-FZ7", "Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Ver.1.0", "Image DateTime": "2007:04:08 14:53:45", "Image YCbCrPositioning": "Co-sited", "Image ExifOffset": "418", "Image PrintIM": "[80, 114, 105, 110, 116, 73, 77, 0, 48, 50, 53, 48, 0, 0, 14, 0, 1, 0, 22, 0, ... ]", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail Orientation": "Horizontal (normal)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "7060", "Thumbnail JPEGInterchangeFormatLength": "8545", "Thumbnail YCbCrPositioning": "Co-sited", "EXIF ExposureTime": "1/30", "EXIF FNumber": "14/5", "EXIF ExposureProgram": "Program Normal", "EXIF ISOSpeedRatings": "100", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2007:04:08 14:53:45", "EXIF DateTimeDigitized": "2007:04:08 14:53:45", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "4", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "3", "EXIF MeteringMode": "Pattern", "EXIF LightSource": "Flash", "EXIF Flash": "Flash fired, auto mode, red-eye reduction mode", "EXIF FocalLength": "6", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "2048", "EXIF ExifImageLength": "1536", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "EXIF InteroperabilityOffset": "6908", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF SceneType": "Directly Photographed", "EXIF CustomRendered": "Custom", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "0", "EXIF FocalLengthIn35mmFilm": "36", "EXIF SceneCaptureType": "Standard", "EXIF GainControl": "None", "EXIF Contrast": "Hard", "EXIF Saturation": "Hard", "EXIF Sharpness": "Hard"}