Iron Manufacture and Milling Technology
Compiled by Brigitte Weinsteiger

Early Middle Ages

• New iron mines and smelting sites are established
• The first literature on mining and metallurgy appears.
• The furnace gains a small chimney of clay and sandstone; gas exit and two openings, one for introduction of the ore and one aperture near the bottom to allow extraction of the "bloom" of iron.
• The introduction of a draft supplied by a pair of bellows.
• The hinged flail, although invented in the fourth century, slowly begins to displace the simple stick for threshing grain.
• Iron use increases (plowshares, harrows, sickles, billhooks, church bells, long swords, battle axes, chain mail).
• The lathe is diffused more widely (2 types, pole lathe and bow lathe)
• Swords, axes, agricultural and household implements are sharpened with a rotary grindstone, as opposed to the earlier whetstone. The rotary grindstone employs a crank.
• The Roman Vitruvian mill and windmill, not generally used in the Mediterranean world, are widely disseminated throughout the medieval world and technologically developed, advancing from a mere 3 horsepower yield to 40-60 horsepower.

10th century

• The shortage of charcoal begins as a result of deforestation; laws limiting its production appear. Efforts to adapt coal for metallurgical purposes are intensified.
• Invention of the drawplate aids blacksmiths in fabricating wire for chain mail, until then painstakingly hammered out at the forge.

11th century

• Water-driven bellows and hammers appear in the eastern Alps and Silesia.

12th century

Early 12th century
• Guilds of craftsmen, including metalworkers, join guilds of merchants.
• The blacksmith's work is in higher demand as building and commerce increase. Carpenters required nails, saws and hammers; masons, mallets, picks, wedges and chisels; carters and wagoners, iron axles and parts; millers, iron components of mill machinery; shipbuilders, nails and fittings.
• Surface deposits or iron ore no longer suffice; pits, trenches and tunnels are driven into the earth.
• The long-handled scythe, developed in the Roman Empire, gains a short bar-handle projecting from its long haft.
• Theophilus Presbyter writes De diversis artibus.
Mid 12th century
• The blacksmith moves from the castle as armorer to the village, as the demand for his services to agriculture grow.
• The earliest surviving written record of a postmill is a rental note in Weedly, Yorkshire.
• postmills become popular enough to have the Pope levy a tithe on them.

13th century

Early 13th century
• The windmill becomes the prime-mover on the plains of eastern England, the Low Countries and northern Germany.
Mid 13th century
• Coal is used for the primary stages of iron smelting, although charcoal still predominates.
• Water mill construction rapidly increases, as mill function becomes more specialized.
• The combination of mills and weirs appears, to measure the flow of water to the millrace.
• The technique of raising the carbon content of iron to produce cast iron is discovered
• Threshing begins to be done under cover, far into the winter in great barns, usually on monastic estates.
Late 13th century
• The use of the wheelbarrow reduces the number of necessary laborers by half, particularly for mining ore.

14th century

Early 14th century
• Water-powered stamping mills appear in the Saar.
• Forged iron firearms appear in Germany.
• The first cast iron cannons appear.
• The earliest known blast furnace is built in Europe, at Lapphytten, Sweden.
• The application of waterpower to wiredrawing in Augsburg.
Late 14th century
• The shortage of labor leads to a severe decline in the production of metals.
• The price of iron and charcoal rises.
• Iron needles (with no eye but a closed hook) are produced at Nuremberg.

15th century

Early 15th century
• Casting directly from the furnace into the mould is achieved.
• The Dutch invent the "wipmolen" or hollow postmill.
Mid 15th century
• Eyed iron needles are produced in Low Countries.
• More attention is paid to the legal aspects of mining, smelting and raw material consumption, because the manufacture of bronze and iron contributed powerfully to a state's warlike potential. Wars subsequently increase the demand for and price of iron.
• The scythe replaces the sickle as the primary tool for harvesting grain.
• Attempts are made to make milling simpler and more efficient.
• postmills begin to be built to drive two pairs of stones placed fore-and-aft in the mill, rather than only one pair of stones, as before.
• Saigerhuetten are first erected.
• The iron industry booms.
Late 15th century
Kriegsbuecher and Ruestungsbuecher, describing metalworking in terms of warfare and armament, and Bergwerkbuechlein and Probierbuechlein, essays on mining and assaying, become widespread with the use of the printing press
• The most agriculturally advanced region in Europe, Flanders, develops a scythe with a small half-circle of bent withy attached near the base of the handle, to gather together the cut grain stems.
• Dürer paints his watercolor of a wire mill.

16th century

• Boller proposes using mill-power to shake sieves, thus beginning the mechanization of bolting in milling.
• J.A. Pantheus writes Voarchadumia contra alchimiam, a book of alchemical nature, concerned with the metallurgy of the more precious metals and materials.
• Italian metallurgical engineer, Vanoccio Biringuccio, writes about water-powered wire-drawing mills in his Pirotechnia.
• Wooden box-bellows are invented by Hans Lobsinger of Nuremberg, displacing the older leather ones.
• Blast furnaces reach sizes of around twelve to sixteen feet high and four-and-a-half feet wide.
• Georgius Agricola (Georg Bauer) writes the De re metallica, the great textbook on every aspect of mining.
Late 16th century
• The production of iron by the indirect process, using moulds, or pigs, comes into widespread use, particularly in northern Europe, in the Low Countries, in Sweden and in Britain.
• Lazarus Ecker writes his Treatise describing the foremost kinds of Metallic Ores and Minerals, adding to the previous printed knowledge on assaying.
• Giambattista della Porta is the first to mention the use of the trompe bellows, invented in Italy.
• Agostino Ramelli writes his book on machines, including milling devices, Le diverse et artificiose machine, in Paris.
• Verantius writes Machinae novae in Venice.

17th century

Early 17th century
• Massive deforestation provides a pressing incentive to find a means of smelting iron with coal.
• Sir Hugh Platt supplies a recipe to the brewing industry for making briquettes of raw coal, known as 'coke;' it would later be applied to metallurgical practices.
• Simon Sturtevant and John Rovenzon publish treatises advocating the adoption of coal-burning blast furnaces.
• Georg Engelhard Löhneiss writes on the organization of mining and its employees in the Bericht von Bergwercken.
• Mathurin Jousse describes the sequence of colors on tempering of steel. He also discusses the recognition of good iron or steel, on the basis of fracture.
• Mersenne writes the first serious tests of tensile properties of gold, silver, copper and iron.
• In the Arte de los Metales, Alvaro Alonzo Barba discusses smelting operations as practiced in the gold and silver mines of the New World, but also contains information on European metallurgy.
• Use of the chimney stack to enhance the draught spreads throughout Europe.
• Biringuccio mentions a solar furnace, a German mirror capable of melting a gold ducat.
• Robert Hooke develops a theory of the hardening of steel based on the colors it turns during tempering and relates it to the hardening of other materials by cold working.
Late 17th century
• Blast furnaces double in size.
• The invention of the reverberatory furnace makes it possible to substitute raw coal for charcoal in the process of smelting.

18th century

Early 18th century
• New methods of producing iron and steel are introduced.
• Swedish scientists, Emanuel Swedenborg and Christopher Polhem, improve Swedish metallurgical and mining methods, almost doubling their country's iron production.
• The volume of the Stückofen triples in size from that of 1500.
• Mathurin Jousse writes the first publication, actually one on carpentry, that included viable instructions for the construction of a windmill.
• The first recorded successful experiment in using coke for smelting iron ore, at Bosley, in Shropshire.
• The first reliable treatise on iron metallurgy, Réaumur's essay on the art of converting iron into steel, is written.
• By this time, there are six blast-furnaces and nineteen hammer-forges, besides numerous bloomeries, in the British colonies of North America.
Mid 18th century
• The first known round-house postmills are constructed.
• By employing a continuous process of feeding ore and fuel into the furnace as the pig iron is tapped, furnaces are producing twice the amount of pig iron per day as the first blast furnaces of 1500, while consuming less fuel.
• Cast iron is applied to uses where stone, wood and other metals had formerly served.
• Cast iron gears are used in the mill, allowing for improvements in turning.
• Schlüter's metallurgical handbook is written.
• Edmund Lee patents the automatic fantail, keeping a windmill facing directly into the eye of the wind.
• Good sheet iron is produced by rolling-and slitting-mills.
• John Smeaton presents to the Royal Society the first scientific study of windmill sails.
Late 18th century
• The role of carbon is finally recognized as the essential difference between wrought and cast iron and steel.
• In England, Andrew Meikle invents the spring-sail for windmills, solving the problem of setting and shortening the sail-cloths in poor weather.
• Henry Cort invents the puddling process, in which the evolved heat of coal fuel was transmitted by reverberation to make pig iron into bar iron, ensuring the triumph of coal in iron metallurgy.
• Stephen Hooper invents the roller-reefing sail, allowing all blinds in the windmill sails to be opened and closed simultaneously without stopping the mill.
• The American Oliver Evans designs the first automatic mill for the mass-production of flour, using power-driven roller-mills and cylindrical bolters.