Crush Mills

(Page created 24/10/10)

From an article by John Gavin in the CIHS Bulletin, January 1989)

Early technology provides examples of basic inventions applied to a wide range of tasks. My interest stems from papermaking and this paper is a brief study of one such invention – the edge runner or roller stone mill.

The traditional mill for grinding corn consists of two horizontal stones, a fixed bed-stone and the movable top-stone, or runner, which is vertically pivoted on the stone-axle The stone-axle both drives the runner and can be adjusted to give the correct clearance between the stones. These mills, and the edge-runners, trace their origins to the saddle and rotary quern. In effect the corn mill’s flat runner is rotated through 90 degrees to a vertical position, like a wheel, and its edge (sometimes dressed) becomes the working surface. (It is interesting to note that wind-mill sails and water-wheels underwent a similar rotation). The edge-runner’s axle is horizontal and is usually pivoted at a central point so that the stone follows a circular path on a hard floor or bed stone, or in a trough or trench. Ganged pairs of stones rotate about the centre of their axle, sometimes slightly offset to increase the effective working area. The stones both roll and slide because of the limited radius of the circle and the width of the roller. The small area of contact can exert great pressure. Rollers and beds were shaped to suit a particular purpose. For some tasks edge-runners were replaced by, or were used together with, other machines.

The earliest known roller-mill is the Roman ‘mole olearia’ used to extract olive oil. It consisted of a pair of cylindrical stones pivoted on a vertical post in the middle of a circular trough. The stones were given a clearance to avoid crushing the nut. Olive oil was used for medicine, soap and lamp-oil, as well as for culinary purposes.

Rotary horse power. Atkinson makes the point that horse power for such direct-action mills came into general use from the early 17th century in England, although he cites earlier examples. The power was calculated at 2/3 to 1/2 h.p. but was dependent on the diameter of the turning circle and the use of efficient harness. There are 40 to 50 horse-engine houses to be found in Cumbria. Many have left no architectural evidence. They were mainly used to drive threshing machines (indirectly via a crown wheel). But Brunskill refers to the multiplicity of farm tasks for cutting, crushing and  mixing machines.

Food preparation. Edge-runners could be used for grain like the more usual horizontal millstones (which also crush and grind). They were used for crushing barley for brewing. Horse-driven mills at Middleham Castle, Yorkshire and Knaresborough date from the 16th century. The ‘one crush milne’ at Castle Mills in Kendal in 1755 (JS) may well have been for malting, although it was a mill of many functions. Mike Davies-Shiel notes vertical ‘pearl-barley’ stone made of a hard, fine grit in a number of Cumbrian watermills. Not really edge-runners as they ran inside a wire-meshed drum husking the grain between the stones and the wire. Cider mills ‘for bruising apples’ and other fruit to make ‘pommage’ had single runners (examples in Jersey) or a pair. The 3-4ft stones of gritstone, (limestone would have been affected by the fruit acid), cost a guinea a foot. The crushed fruit was placed in hair bags which were squeezed in a press and the liquor fermented in casks.

Ore-dressing and stone-crushing. Bouch & Jones refer to the German miners at Keswick in the 16th century probably using stampers to crush the ore, as illustrated in Agricola’s De Re Metallica (1556). Yet the book does show horse operated rotary machines for other uses. Roller-mills elsewhere in the country were employed crushing lead ore, sandstone, limestone and chalk;  in the building trade to mix mortar and for brick-making; and for grinding clay for potters, and flint and other materials for glass-making. Pottery and clay-pipes were made at Dearham and Little Broughton in the 18th century, and there was a glass works at Cross Canonby.

Textiles and dyestuffs. Rollers were used for grinding colours including those from logwood and brazil (after rasping or chipping) by drysalters such as Mr Henry Scarisbrick of Kendal in the 18th century. Dockwray Hall Mills, Kendal, was a woollen and drysalter’s mill, and Scar Foot Mill, Mealbank, ground indigo (and pepper!). (JS). Indigo came from woad which was still being milled by portable machinery until the 1914-18 war in some areas of the country. Oil of rapeseed, coleseed and mustard seed provided preservative dressings for wool and leather. Linseed, hempseed and poppyseed oils were drying oils that were used for paints, artists’ varnishes and printers’ ink. These plants were grown very generally in this country, and certainly Yorkshire is noted by Rees for the production of oil. Linseed and rapeseed have very hard, smooth kernels, and a complex process, also using heat, was used to crush the seed and express the oil, leaving a residue of cattle-cake (AR). Edge runners were also used in hemp mills and for crushing bark for tanning leather.

Paper. The pair of rollers were up to 6ft in diameter, width 10in (usually dressed), weight c.3 tons each and running, off-set, on a stationery bed-stone. They were used, usually in a string, for treating waste paper, wood pulp, kraft pulp and grease-proof paper. The power requirement was high : 30hp at 10-15 rev/min with an output of 4-6 cwt/hour. They were economically viable only “where ample water-power was available”; although as their action defibred and fibrillated pulp, power was saved on the beating engines. Introduced in the 19th century they were still in use in the late 1960s. Now probably all replaced by more efficient machinery with greater output. One is preserved at the Burneside Mill. A set of stones is displayed in the village of Staveley.

Gunpowder. The full process is described and illustrated in JDM/MDS. Edge runners were used in the incorporating mills where the ‘green charge’ was mixed under pressure to the correct density. Pairs of limestone or cast-iron runners with a common axle ran above a bed-stone within a bowl-shaped ‘corbin’. Suspended runner gear gave a clearance of 2ins or more allowing a larger charge to be ground and avoiding the risk of explosion from friction

References

[FA] The horse as a source of rotary power : F.Atkinson, Newcomen Soc Trans, Vol XXXIII, 1960-1, pp31-56

[B&J] The Lake Counties 1500-1830 : C.M.L.Bouch & G.P.Jones, Manchester University Press, 1961, p119

Vernacular architecture of the Lake Counties : R.W.Brunskill, Faber, 1974,8

Modern papermaking : R.H.Clapperton & W.Henderson, 1929

[MDS] Watermills of Cumbria : M.Davies-Shiel, Dalesman, 1958

A handbook of papermaking : R.R.A.Higham, 1963,8

History of the county of Cumberland : W.Hutchinson, EP Publishing, 1974 rpt

[JDM/MDS] Industrial archaeology of the Lake Counties : J.D.Marshall & M.Davies-Shiel, David & Charles, 1969,77

[WHP] Microcosm : ….Arts, agriculture and manufactures : W.H.Pyne, 1808

[AR] Early trades and industries : A Rees, 1808, reprint 1974

[RWS] Paper technology : R.W.Sindall, 1910

[JS] Water-power mills of South Westmorland : J.Somervell, Titus Wilson, 1930