Herefordshire Through Time
Herefordshire Through Time
The iron industry of the 18th century was made up of several component parts. Pig iron was made at the furnaces and then refined into wrought iron at the forges. One of the most important iron-making regions in Britain at this time was the West Midlands. In the early 18th century the West Midlands produced over 40% of the national pig iron output and nearly 60% of bar iron. The forges in the Birmingham area also consumed about 50% of the pig iron produced in the Forest of Dean. An important position in the West Midlands iron industry was occupied by the Bringewood interests of the Knight family of Herefordshire.
The River Teme produced enough water power to sustain the working of both a furnace and a forge at Bringewood, so pig iron could be produced and refined into wrought iron on the same site, so keeping down transport costs. The origin of iron-making activities at Bringewood dates back as far as the 16th century, when in 1584 a lease of Bringewood Forge was granted by Lord Craven to Francis Walker.
In 1698 Richard Knight took a 21-year lease on Bringewood. However, one problem stood in the way of the successful operation of the Bringewood ironworks - the difficulty of acquiring the vast amounts of charcoal needed as fuel. The possible output of iron from the furnace in 1717 was assessed as 340 tons each year, but it had not reached this figure because of the shortage of wood.
In 1723 Richard Knight purchased the freehold of Leintwardine, the Chase of Bringewood and the Forest of Mochtree, possibly to secure more wood supplies. However, the fuel cannot have been enough (or perhaps it was the water supply that was lacking) for up until the mid-1750s the furnace at Bringewood was only in blast on alternate years.
In order to supply his forges at Bringewood and Morton with pig iron Richard Knight built a furnace at Charlcotte. Ironstone for the Bringewood furnace was obtained mainly from the Coal Measure deposits of the Clee Hills in Shropshire. In 1742 Richard Knight actually bought Clee Hill.
In 1733 Richard Knight retired and leased his investments to his sons Edward and Ralph (who lived locally to Bringewood). On his death in 1745 the landed estates passed to his eldest son Richard, who purchased Croft Castle in 1746. On Richard's death in 1765 the estates passed to his nephew Richard Payne Knight. The Bringewood Ironworks remained with Edward Knight but the operation of the ironworks and the land that it stood on had diverged.
During the period of 1734-50 the greatest output of pig iron in a year was 941.5 tons and the lowest was 123 tons. Most of the forge output at this time was purchased by the Midland's scythesmiths and ironmongers.
In the 1730s Edward Knight began to build a rolling mill at Bringewood in order to enter the tinplate trade. Tinplate consists of a thin sheet of iron covered with a thin layer of tin, which makes the sheet durable and protects it from rust. The making of tinplate needed large amounts of water for cleaning and driving the rolling mills, cheap fuel, and a proximity to a supply of wrought iron.
All the tinplate manufactured at Bringewood would have to be transported overland along rough tracks to Bewdley and then on the River Severn for sale or transhipment. Any damage to the tin layer would render the sheet un-saleable as the iron layer would be exposed to the elements and thus at risk from rust. Needless to say, the transport of tinplate resulted in a considerable number of rejects. For this reason, Edward Knight decided to produce only the iron backplate at Bringewood. The backplate would be transported in tallow and soft soap to prevent it rusting. The main markets for tinplate were the London and Bristol merchants and the Black Country.
At this time, Bringewood was still operating on alternate years, and profits rose and dipped accordingly. Ralph Knight died in 1754 and the management of Bringewood and Charlcotte fell to Edward Knight.
The 1750s were an important time for the iron trade with an increase in demand fuelled by the hostilities of the Seven Years War. Edward Knight decided to rebuild the chafery and fire it with coal, which he could obtain from Clee Hill. The charcoal could then be reserved for the furnace and from 1756-1776 the Bringewood furnace was in blast each year.
During the 1750s Bringewood operated totally with iron produced at its own furnace and from Charlcotte. In the 1760s it suffered as ironstone and charcoal prices rose. In 1774-75 tinplate manufacture at the site ceased.
In 1779 the furnace at Bringewood was blown out, although the forge continued to work. In 1780 Edward Knight, the last tenant for life on the lease, died and his sons James and John were undecided about the lease renewal. This indecision was of great concern to Richard Payne Knight, the owner of the Downton Castle Estate on which the works were situated.
Richard Payne Knight was the cousin of James and John and the MP for Leominster at the time of Edward's death. He had spent much of his youth abroad. The stopping of work at Bringewood would have hit his income considerably. He tried to entice James and John into taking a further lease with a view to putting the furnace back into blast. James Knight argued that the ironstone would be too expensive and difficult to get hold of.
In 1783 Richard Payne Knight took over the possession of the land and ironworks. A lot of restoration to the site was needed and the bill for repairs came to £311. On completion Richard Payne Knight negotiated to lease the forge to William Downing of Strangeworth Forge at Pembridge, Benjamin Giles of Hope in Shropshire and John Longmore of Cleobury Mortimer. In the end it was leased to Downing and Giles in 1784 for 31 years with a yearly rent of £114. There was also a clause that £20 had to be paid for every pheasant or partridge killed on the land.
Furnaces took the form of a truncated pyramid approximately 25ft in height. The external shape was square but the interior was round. Bringewood had the second highest output of all the furnaces owned by the Knight family.
The manufacture of pig iron needs iron ore, a fuel, a flux and a blast of air to raise the temperature. The charcoal-fired furnace of the 18th century was usually fired through a single hole called a tuyere, which was normally found in the side. The blast of air was produced by a pair of large bellows activated by the cogs of a waterwheel.
A typical ironworks' bellows was wedge shaped with top and bottom boards made of ash wood lined with tin or iron. The sides were made up of around 18 bull's hides. The bellows were 18½ft long, 2¼ ft deep and 4½ ft wide at the back. The leather of the bellows needed a lot of lubrication while working, and butter and tallow were used.
During the 1750s some ironmasters began to use iron cylinders or cylinders and pistons. In 1762 James Knight patented a method of blowing a furnace with pistons working in square blowing tubs. The pistons were powered through a system of chains and levers from a waterwheel. However, it is thought that this invention was never used in the furnace.
Bringewood took its iron ore from Clee Hill, and at Bringewood the price of iron ore from 1734 to 1754 increased from the equivalent of £0.875 to £1.02 and in 1756/7 it rose to £1.22, but after the initial period of the seven years it dropped back to £1.07 in 1758/9.
The smelting of iron would require the furnace to be in blast for several days, and a large supply of charcoal would be needed on site before the furnace was lit. The charcoal would be kept in a special store and treated with great care. The soft charcoal was easily damaged, and small pieces and dust could not be used in the smelting process.
In the early days wood for charcoal was cut down haphazardly but it did not take long for the landowners to realise that wood could be specifically cultivated for the iron industry. Trees could be grown and then cut at ground level to re-grow for further re-cutting in 12-20 years' time. This coppicing allowed the landowner to conserve and re-use the roots of his trees. The cutting of the wood took place between 1st November and 30th March.
Bringewood was fairly well served in its local area for wood, and during 1733-40 all the charcoal it used came from no further than eight miles away. By 1771-73 charcoal was coming from up to 14 miles away.
The great disadvantage of charcoal as fuel was that supply was never in direct relation to demand. Boom conditions in the industry might encourage landowners to increase their coppice acreage, but on average it would take 16 years for these trees to mature for cutting, by which time demand may have fallen. In times of recession there would often be a glut of wood.
In 1736, the woodmasters of the English Midlands petitioned Parliament asking for a duty to be imposed on foreign iron. They blamed the import of foreign iron for the closure of some English ironworks. In 1737 Edward Knight gave evidence to a Parliamentary Commission on this subject.
At Bringewood in 1750 a ton of pig iron was valued at £6, in 1754 it had risen to £6.75 and £8 in 1758. The mid-1760s saw a rise in the price of charcoal at Bringewood which continued into the 1770s and helped make it uncompetitive compared to other furnaces.
The pig iron produced by a furnace was converted into the more desirable wrought iron at a forge.
The conversion of the pig iron into wrought iron was carried out in the finery. A typical finery measured 5ft 3in by 6ft 3in and was topped by a chimney. The heat was increased by means of a blast of air directed through a tuyere on to the burning material. The back and tuyere side were closed in but the two remaining sides were left open for the finer to work the hearth. The hearth had sides of 2ft 3in and 1ft 11in, and was lined with cast iron plates.
The work at the finery was carried out in several stages. First the hearth was lined with fine charcoal dust and the fireplace filled with charcoal, and a pig of iron put in a suitable place for melting. The fire was lit and a blast of air from water-powered bellows was introduced. The pig iron was then gradually pushed forward over wooden rollers into the hearth. The iron would melt and trickle down in drops. The finer would then begin to stir and work the iron with a long iron bar called a ringer. During melting the iron would decarburise. The metal ran to the bottom of the hearth, which was cooler, and then turned into a semi-solid state. The slag, which separated during this process, remained in a slag bath until it reached the level of the slag hole where it was tapped off.
After this first fusion another period of refining took place. The semi-solid iron was broken up and, using an iron bar called a furgon or furgeon, those parts that were not sufficiently decarburised were raised towards the tuyere. All sides of the iron were exposed to the blast and this was repeated until all parts of the iron were sufficiently refined.
During the last stage of the process the mass of iron was raised and held again in front of the blast of air from the tuyere. The iron melted for a third time and formed pasty lumps at the bottom of the hearth. The finer gathered these lumps together into a ball which was called a bloom or loop. The bloom was a spongy mass of malleable iron whose cracks were filled with slag. The whole process of refining and balling took about an hour.
The bloom was then placed on an iron plate and beaten with a large hammer to remove surface charcoal and slag. The bloom was then shingled or hammered by a water-driven hammer to force out some more of the slag and to consolidate it into a 2ft sq mass of iron.
The bloom was then returned to the finery where it was raised to welding temperature to sweat out any impurities. The bloom was then taken back to the water-driven hammer to be forged into an ancony. This was an elongated piece of iron, the middle of which was around 3ft long and bar shaped with each end as a thick knob, one larger than the other. The slag was now in the ends.
The process was then completed at the other hearth, which was called the chafery. The chafery was similar to the finery except for being slightly larger. In the chafery the smaller of the two unfinished ends was heated for 15 minutes and then consolidated and forged under the power hammer into the shape of the middle bar. The thicker end required two heatings. In the chafery a higher temperature was required to sweat out carbonaceous particles still in the iron. The hot iron was finally forged under the hammer into the shape of the bar and the rough ends cut by chisels. The chafery could be fired with charcoal or coal. In 1755/6 the charcoal-fired chafery at Bringewood ironworks was turned over to coal firing.
Bringewood was one of the largest forges owned by the Knight family, and it was made up of three fineries and one chafery. At the end of the 1870s Bringewood forge had three bellows, each powered by a waterwheel. There was also a waterwheel to power a hammer and another waterwheel to power the chafery hammer. This was in addition to the large waterwheel powering the blowing tubs at the furnace and five waterwheels at the rolling and slitting mills.
[Original author: Miranda Greene, 2005]