Glossary of mill machinery

Last updated June 07, 2023

Diagram showing an underdrift windmill MeophamGreen.svg — Diagram showing an underdrift windmill

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.^[1]^[2]

Watermill machinery

A Waterwheel Waterwheel.jpg — A Waterwheel

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.

Windmill machinery

Overdrift millstones Overdrift.jpg — *Overdrift* millstones

Bedstone: The Bedstone is the bottom of a pair of millstones. It does not move. The upper stone is called the Runner Stone.

Brake Wheel: The Brake Wheel is the main driving wheel in a Smock or Tower mill, and in some post mills. It is carried on the Windshaft and drives the Wallower on the Upright Shaft

Buck: The Buck is an East-Anglian term for the body of a post-mill.

Centrifugal governors: Governors are used to regulate the distance and pressure between millstones in windmills in the 17th century.^[3]

Crown Tree: The Crown Tree is the central, single baulk of timber, usually oak, that rests on top of the post in a post mill. Attached to it are the side-girts and the rest of the frame of the buck.

Crown wheel: In a windmill, a Crown Wheel is an auxiliary gear on the Upright Shaft.

Fantail: A fantail is a small windmill which is used to keep a windmill facing into the wind automatically.

Great Spur Wheel: The Great Spur Wheel is carried on the Upright Shaft. It drives the Stone Nuts. Millstones driven by the Great Spur Wheel can be either Overdrift or Underdrift.

Head Wheel: The Head Wheel is carried on the Windshaft in a Post Mill and has a brake around its circumference. It drives a Stone Nut, Millstones driven by the Head Wheel are always Overdrift stones.

Middling

See Stock

Overdrift: Millstones driven from above are known as Overdrift stones.

Pintle: The pivot centering a post mill on top of the main post.

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.

Sails: The Sails are the source of power in a windmill. They are carried on the Windshaft. Most windmills had four sails, although some had five (Boston), six (Waltham, Lincs) or eight sails Heckington, Lincs and there is one recorded twelve sailed windmill (Cottenham, Cambs).

Common Sails have a lattice framework over which a sailcloth is spread. These were the earliest type of sails in northern European windmills.

Spring Sails, invented in 1772 by Andrew Meikle, have shutters adjusted by a spring. Each sail is adjusted individually and, as with Common Sails the mill has to be stopped to enable an adjustment to be made.

Roller Reefing Sails, invented in 1789 by Stephen Hooper, use a canvas strip wound around a roller in the place of shutters. The mill does not have to be stopped in order to adjust the sails.

Patent Sails, invented in 1819 by William Cubitt, combine the shutters of the Spring Sail with the automatic adjustment of the Roller Reefing Sail. Single Patents have shutters on the trailing side of the sail, Double Patents have shutters on both sides of the sail for its whole length.

Samson Head: An iron collar and plate bearing that fits over the pintle of a post-mill's post, that supports the weight of the crown tree, around which the buck of the mill is constructed. An example is visible at High Salvington windmill.

Stock: The beam that passes through the canister of the windshaft, which the sails are bolted onto.

Stone Nut: The Stone Nut is a small gear driven by the Great Spur Wheel, Head Wheel, or Tail Wheel. It drives the Runner Stone either from above (Overdrift) or below (Underdrift).

Tail Wheel: The Tail Wheel is carried on the Windshaft in a Post Mill and drives a Stone Nut. Millstones driven by the Tail Wheel are always Overdrift stones.

Trestle: The Trestle is the substructure of a Post Mill, usually enclosed in a protective structure called a roundhouse, which also serves as a storage facility. Post mills without a roundhouse are called Open Trestle Post Mills.

Underdrift: Millstones driven from beneath are known as Underdrift stones.

Upright Shaft: The Upright Shaft is the main vertical shaft found in Smock and Tower mills. It is also found in some Post mills. It carries the Wallower at its top end, and a Great Spur Wheel at the bottom end. The Great Spur Wheel drives two or more Stone nuts.

Wallower: The Wallower is a driven gear at the top of the Upright Shaft in Smock, Tower and some Post mills. It is driven by the Brake Wheel

Windshaft: The Windshaft carries the Sails and also the Brake Wheel (Smock and Tower mills, and in some Post mills) or the Head Wheel and Tail Wheel in a Post Mill. Windshafts can be wholly made of wood, or wood with a cast iron Poll End (where the Sails are mounted) or entirely of cast iron.

Related Research Articles

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.

Union Mill is a Grade I listed smock mill in Cranbrook, Kent, England, which has been restored to working order. It is the tallest smock mill in the United Kingdom.

Black Mill, or Borstal Hill Mill is a smock mill in Whitstable, Kent, England that was built in 1815. It is now a part of a private residence at the end of Millers Court.

Blackdown Mill or Cherry Clack Mill is a grade II listed smock mill at Punnetts Town, East Sussex, England, which has been restored.

<span class="mw-page-title-main">Shiremark Mill, Capel</span>

Shiremark Mill, also known as Kingsfold Mill or Capel Mill was a listed Smock mill at Capel, Surrey, England, which was burnt down in 1972.

South Ockendon Windmill was a Smock mill at South Ockendon, Essex, England which collapsed on 2 November 1977.

Stock Windmill is a grade II* listed tower mill at Stock, Essex, which has been restored.

Upthorpe Mill is a Grade II* listed post mill and scheduled monument at Stanton, Suffolk, England, which has been restored to working order.

Cromer Windmill, restored in four stages between 1967 and 1998, is a Grade II* listed post mill at Cromer, Ardeley, Hertfordshire, England.

De Berk is a smock mill in Barger-Compascuum, Netherlands. It was built in 1983.

De Bente is a smock mill in Dalen, Netherlands. It was built in 1814. The mill has been restored to full working order. It is listed as a Rijksmonument, number 44563

<span class="mw-page-title-main">De Sterrenberg, Nijeveen</span> Windmill in Drenthe, the Netherlands

De Sterrenberg is a smock mill in Nijeveen, Drenthe the Netherlands. It was built in 1977. The mill is listed as a Rijksmonument, number 30957.

De Zwaluw is a smock mill in Burdaard, Friesland, Netherlands which is working commercially. The mill is listed as a Rijksmonument, number 15585.

De Zwaluw is a smock mill in Oudemolen, Drenthe, the Netherlands. It was built in 1837 and is listed as a Rijksmonument, number 38148.

De Verwachting is a smock mill in Hollum, Friesland, Netherlands which was built in 1991 and is in working order.

De Sweachmermolen is a smock mill between Langweer and Boornzwaag, Friesland, Netherlands which was built in 1782. The mill has two functions: it is a drainage mill and a corn mill. It has been restored to working order as a drainage mill and is listed as a Rijksmonument, number 13241.

<span class="mw-page-title-main">Munnekezijlstermolen, Munnekezijl</span>

The Munnekezijlstermolen is a smock mill in Munnekezijl, Friesland, Netherlands which was built in 1856 and is in working order. The mill is listed as a Rijksmonument.

Veldkamps Meuln is a 19th-century tower mill in the village of Bellingwolde in the Netherlands.

Windlust is a smock mill in Wolvega, Friesland, Netherlands which was built in 1888 and is in working order. The mill is listed as a Rijksmonument.

Johanna, De Korenbloem or De Molen van Schennink is a tower mill in Culemborg, Gelderland, Netherlands which was built in 1888 and has been restored to working order. The mill is listed as a Rijksmonument.

References

↑
- Reynolds, John (1974). Windmills and Watermills. London: Hugh Evelyn Ltd. ISBN 0-238-78943-8. covers most entries
↑
- Freese, Stanley (1957). Windmills & Millwrighting. Newton Abbot: David & Charles. ISBN 0-7153-5365-9. covers Buck, Crown Tree, Pintle, Samson Head
↑ Hills, Richard L (1996), Power From the Wind, Cambridge University Press

External links

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[Book-1] 
Reynolds, John (1974). Windmills and Watermills. London: Hugh Evelyn Ltd. ISBN 0-238-78943-8. covers most entries

[mwAXU] Reynolds, John (1974). Windmills and Watermills. London: Hugh Evelyn Ltd. ISBN 0-238-78943-8. covers most entries

[Freese-2] 
Freese, Stanley (1957). Windmills & Millwrighting. Newton Abbot: David & Charles. ISBN 0-7153-5365-9. covers Buck, Crown Tree, Pintle, Samson Head

[mwAYA] Freese, Stanley (1957). Windmills & Millwrighting. Newton Abbot: David & Charles. ISBN 0-7153-5365-9. covers Buck, Crown Tree, Pintle, Samson Head

[3] Hills, Richard L (1996), Power From the Wind, Cambridge University Press

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