The slitting mill was a watermill

Watermill

A watermill is a structure that uses a water wheel or turbine to drive a mechanical process such as flour, lumber or textile production, or metal shaping .- History :...

 for slitting bars of iron

Iron

Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 into rods. The rods then were passed to nailers who made the rods into nails, by giving them a point and head.

The slitting mill was probably invented near Liège

Liège

Liège is a major city and municipality of Belgium located in the province of Liège, of which it is the economic capital, in Wallonia, the French-speaking region of Belgium....

 in what is now Belgium

Belgium

Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...

. The first slitting mill in England

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 was built at Dartford

Dartford

Dartford is the principal town in the borough of Dartford. It is situated in the northwest corner of Kent, England, east south-east of central London....

, Kent in 1590. This was followed by one on Cannock Chase

Cannock Chase

Cannock Chase is a mixed area of countryside in the county of Staffordshire, England. The area has been designated as the Cannock Chase Area of Outstanding Natural Beauty. The Chase gives its name to the Cannock Chase local government district....

 by about 1611, and then Hyde Mill in Kinver

Kinver

Kinver is a large village in South Staffordshire district, Staffordshire, England. It is in the far south-west of the county, at the end of the narrow finger of land surrounded by the counties of Shropshire, Worcestershire and the West Midlands. The nearest towns are Stourbridge in the West...

 in 1627. Others followed in various parts of the England where iron was made. However there was a particular concentration of them on the River Stour

River Stour, Worcestershire

The Stour is a river flowing through the counties of Worcestershire, the West Midlands and Staffordshire in the West Midlands region of England. The Stour is a major tributary of the River Severn, and it is about in length...

 between Stourbridge

Stourbridge

Stourbridge is a town within the Metropolitan Borough of Dudley, in the West Midlands of England. Historically part of Worcestershire, Stourbridge was a centre of glass making, and today includes the suburbs of Amblecote, Lye, Norton, Oldswinford, Pedmore, Wollaston, Wollescote and Wordsley The...

 and Stourport, where they were conveniently placed to slit iron that was brought up (or down) the River Severn

River Severn

The River Severn is the longest river in Great Britain, at about , but the second longest on the British Isles, behind the River Shannon. It rises at an altitude of on Plynlimon, Ceredigion near Llanidloes, Powys, in the Cambrian Mountains of mid Wales...

 before it reached nail

Nail (engineering)

In woodworking and construction, a nail is a pin-shaped, sharp object of hard metal or alloy used as a fastener. Formerly wrought iron, today's nails are typically made of steel, often dipped or coated to prevent corrosion in harsh conditions or improve adhesion...

ers in the Black Country

Black Country

The Black Country is a loosely defined area of the English West Midlands conurbation, to the north and west of Birmingham, and to the south and east of Wolverhampton. During the industrial revolution in the 19th century this area had become one of the most intensely industrialised in the nation...

.

The slitting mill consisted of two pairs of rolls turned by water wheel

Water wheel

A water wheel is a machine for converting the energy of free-flowing or falling water into useful forms of power. A water wheel consists of a large wooden or metal wheel, with a number of blades or buckets arranged on the outside rim forming the driving surface...

s. Mill bars were flat bars of iron about three inches wide and half an inch thick. A piece was cut off the end of the bar with shears powered by one of the water wheels and heated in a furnace. This was then passed between flat rolls which made it into a thick plate. it was then passed through the second rolls (known as cutters), which slit it into rods. The cutters had intersecting grooves, which sheared the iron lengthways.

Further reading

• H. R. Schubert, History of the British Iron and Steel Industry ... to 1775 AD (Routledge, London, 1957) 304-12.
• W. K. V. Gale, The Black Country Iron Industry: a technical history (Iron and Steel Institute, London, 1966), 14-15.
• P. W. King, 'The Development of the Iron Industry in South Staffordshire in the 17th century: history and myth' Trans. Staffs. Arch. & Hist. Soc. XXXVIII (1999 for 1996-7), 62-4.