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A grindstone, also known as grinding stone, is a
Aboriginal grinding grooves, or axe-grinding grooves, have been found across the Australian continent. The working edge of the hatchet or axe was sharpened by rubbing it against an abrasive stone, eventually leading to the creation of a shallow
A grindstone, also known as grinding stone, is a sharpening stone
Sharpening stones, or whetstones, are used to sharpening, sharpen the edges of steel tools such as knife, knives through grinding and Honing (metalworking), honing.
Such stones come in a wide range of shapes, sizes, and material compositions. ...
used for grinding or sharpening ferrous
In chemistry, iron(II) refers to the chemical element, element iron in its +2 oxidation number, oxidation state. The adjective ''ferrous'' or the prefix ''ferro-'' is often used to specify such compounds, as in ''ferrous chloride'' for iron(II ...
tools, used since ancient times. Tools are sharpened by the stone's abrasive qualities that remove material from the tool through friction in order to create a fine edge. Similar to sandpaper
upright=1.35, Sheets of sandpaper with different grit sizes (40 (coarse), 80, 150, 240, 600 (fine))
Sandpaper, also known as coated abrasive or emery paper, is a type of material that consists of sheets of paper or cloth with an abrasive substa ...
, each stone has a different grit that will result in sharper or duller tools. In Australia, Aboriginal peoples created grinding grooves by repeated shaping of stone axe
Stone tools have been used throughout human history but are most closely associated with prehistoric cultures and in particular those of the Stone Age. Stone tools may be made of either ground stone or knapped stone, the latter fashioned by a c ...
s against outcrop
An outcrop or rocky outcrop is a visible exposure of bedrock or ancient superficial deposits on the surface of the Earth and other terrestrial planets.
Features
Outcrops do not cover the majority of the Earth's land surface because in most p ...
s of sandstone
Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
.
History and description
Grindstones have been used since ancient times, to sharpen tools made of metal. They are usually made fromsandstone
Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
.
Grinding grooves
Aboriginal grinding grooves, or axe-grinding grooves, have been found across the Australian continent. The working edge of the hatchet or axe was sharpened by rubbing it against an abrasive stone, eventually leading to the creation of a shallow oval
An oval () is a closed curve in a plane which resembles the outline of an egg. The term is not very specific, but in some areas of mathematics (projective geometry, technical drawing, etc.), it is given a more precise definition, which may inc ...
-shaped groove over time, The grooves vary in length from up to , and can be up to wide and deep. They are often found near water, which was sprinkled on the stone during grinding to reduce dust.
Machines
Grindstone machines work by spinning a circular piece of stone around its center point. These machines usually have pedals for speeding up and slowing down the stone to control the sharpening process. The earliest known representation of a rotary grindstone, operated by a crank handle, is found in theCarolingian
The Carolingian dynasty ( ; known variously as the Carlovingians, Carolingus, Carolings, Karolinger or Karlings) was a Frankish noble family named after Charles Martel and his grandson Charlemagne, descendants of the Arnulfing and Pippinid c ...
manuscript known as the Utrecht Psalter
The Utrecht Psalter (Utrecht, Universiteitsbibliotheek, MS Bibl. Rhenotraiectinae I Nr 32.) is a ninth-century illuminated manuscript, illuminated psalter which is a key masterpiece of Carolingian art; it is probably the most valuable manuscript ...
. This pen drawing from about 830 goes back to a late antique original. The Luttrell Psalter
The Luttrell Psalter (British Library, Add MS 42130) is an illuminated manuscript, illuminated psalter commissioned by Sir Geoffrey Luttrell (1276–1345), lord of the manor of Irnham in Lincolnshire, written and illustrated on parchment ''circa'' ...
, dating to around 1340, describes a grindstone rotated by two cranks, one at each end of its axle. Around 1480, the early medieval rotary grindstone was improved with a treadle and crank mechanism.
See also
*Lathe
A lathe () is a machine tool that rotates a workpiece about an axis of rotation to perform various operations such as cutting, sanding, knurling, drilling, deformation, facing, threading and turning, with tools that are applied to the w ...
*Millstone
Millstones or mill stones are stones used in gristmills, used for triturating, crushing or, more specifically, grinding wheat or other grains. They are sometimes referred to as grindstones or grinding stones.
Millstones come in pairs: a s ...
*Punch (tool)
A punch is a tool used to indent or create a hole through a hard surface. They usually consist of a hard metal rod with a narrow tip at one end and a broad flat "butt" at the other. When used, the narrower end is pointed against a target surf ...
* Grindstone City Historic District
References
Sources
* * Woodworking Grinding and lapping Knives {{metalworking-stub