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story:Rational manufacture

scene:The Portsmouth blockmaking machinery

The Portsmouth blockmaking machinery
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Diagram showing the rigging of a merchant ship. Plate taken from The Art of Rigging by Captain George Biddlecombe, 1848.
The Portsmouth blockmaking machinery
In 1805, Britain's Admiral Nelson won his famous naval victory at Trafalgar. As his ships outmanoeuvred the opposing French fleet they relied on pulley blocks to raise and lower their sails and to help with countless tasks on board.
In the same year the manufacture of these pulley blocks was taken over by the first ever suite of single-purpose machines working as a 'production line'. This machinery played a major role in manufacturing history.
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Interior of Portsmouth block mill, c.1900.
Diagram showing the rigging of a merchant ship with pulley blocks. Plate taken from The Art of Rigging by Captain George Biddlecombe, 1848.
A ship's pulley block, made on the Portsmouth blockmaking machinery, 1819. As many as 922 of these blocks were needed on a single 74-gun naval vessel.
New processes:
At the end of the eighteenth century, blockmaking, like other manufacturing, was largely done by hand. Some simple machines were used but a skilled workman using hand tools completed most of the work.
Some industries had already been partially mechanised. What was remarkable in British blockmaking was the almost 'complete' move to mechanisation.
Separate operations were performed using single-purpose machines with the number of each type built in proportion to the duration of the operation. This created a steady flow of production.
The development of the blockmaking process came at a time when Britain's war with France created a high demand for ship blocks. By 1800 the Royal Navy needed 100,000 every year.
The Navy was under pressure to embrace new production methods.
Sir Samuel Bentham, the Inspector-General of the Navy Works appointed in 1796, had already introduced some power-driven machinery. His re-organisation of Portsmouth dockyard showed that up-to-date methods were taken increasingly seriously.
It was against this background that in 1801 Marc Isambard Brunel approached Bentham with a scheme for making blocks with a suite of special machines. Brunel had already offered his inventions to the main suppliers of blocks to the Admiralty, Taylors of Southampton. However they had refused them, considering their own methods good enough.
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Sir Samuel Bentham (1757-1831). It is unlikely that Bentham contributed to any major element of the machinery's design, and arguments tend to focus on Brunel and Maudslay's contributions.
Marc Isambard Brunel. Brunel discussed the idea of blockmaking machinery with Henry Maudslay. However, how detailed those plans were is unknown. Brunel also made extensive drawings in a notebook but it is unclear whether these were design records or records of what was finally made. Arguments continue today about the degree of credit due to Brunel.
Engraving of blockmaking at Taylors of Southampton, 1794, showing a horse-driven saw and lathe.
From plans to machines:
Brunel's plans needed development and a skilled mechanic was needed to make the machines. Through a friend, Brunel contacted Henry Maudslay.
Initially Brunel showed him plans without explaining the machine's use in order to maintain secrecy. However after Maudslay had seen a couple of drawings he cried: 'Ah! Now I see what you are thinking of; you want machinery for making blocks.'
Not only had Maudslay understood the drawings themselves, a rare enough skill at that time, but he showed that he grasped their significance.
From this point the two collaborated. With help from Bentham the mechanical process of making ship's blocks had become a reality. By 1805 machinery took over production of the Navy's entire block supply.
However because all three men played such an important role in the development of the plant it has always been arguable as to who was the real inventor of the machinery.
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Shaping machine from the Portsmouth blockmaking machinery, 1804. In many respects the machinery represented the shape of things to come for the design of machine tools.
Henry Maudslay (1771-1831). Lithograph by H. Grevedon, 1827. Some historians consider it highly likely that Maudslay 'filled in the gaps' in Marc Brunel's blockmaking plans and made the machines truly viable.
The machines
The machines are of major historical importance. They were purpose-built, producing standard components in large quantities. This production came at a time when most products were manufactured individually with every component being different from the next.
The machines were made in three sets to make a range of different sized blocks. The first set (for medium-sized blocks) started work in 1803.
Each machine carried out a single process. In total, 45 machines were needed to carry out 22 different processes.
The designs for the machines were highly innovative. Until this time machine tools were usually made of wood, these were nearly all made entirely of metal. As a result the machines and their products were exceptionally accurate.
The machines also introduced the use of markings on the wood. The markings were impressed into the wooden shells by the boring machine at the beginning of the process. In all the following machines these indentations were registered on corresponding projections to ensure proper alignment.
Among the many advantages to these machines was that they allowed production methods to become far less labour intensive, being carried out mainly by machine operators. As Richard Beamish wrote in his book 'Life of Sir Isambard Brunel: '...So that ten men, by the aid of this machinery, can accomplish with uniformity, celerity and ease, what formerly required the uncertain labour of one hundred and ten.'
The Portsmouth blockmaking machinery proved to be exceptionally reliable and enduring. They met the Royal Navy's entire requirement for blocks and some were still in operation as late as the mid-twentieth century.
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Circular saw from the Portsmouth blockmaking machinery, 1804
Explore the machines
A pulley block comprises a pulley or sheave turning on a pin inside a shell. Its main use was in the management of the sails of the ship. The development of the pulley block was fundamental to the workings of a ship as it meant heavier loads could be carried with less power. Increasing the number of pulleys increased the weight that could be moved.
Here we explore two of the processes that the blockmaking machinery embodied: making the block shells and sheaves. Both of these processes took place simultaneously. A third simultaneous process made the pin that formed the sheave's axle, completing the finished block. We begin with shell-making.
Shell-makingSteps in the production of the shell:
'Pendulum' saw: This machine, essentially a circular saw on a pivoting frame, cut the wood for making the block shells from an elm log. The block is rectangular.
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'Pendulum' saw, 1803.
Block of wood.
Boring machine: This machine carries out the boring of the shells in two areas. One drill bores the hole for the pivot pin that passes through the shell on which the sheave runs. The other bores a larger initial hole at right angles that will be elongated by the mortising machine chisel to form the slot for the sheave.Images with this text:
Boring machine, 1803.
A wooden block with a small hole in the top and on the side and two larger holes in the front.
Mortising machine: Shells are taken from the boring machine into the mortising machine to lengthen the hole initially made by the boring machine. The mortising machine chisels out the slot in which the sheave will turn.
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Mortising machine, 1803.
A wooden block with two elongated holes in the front
Corner Saw: The block was placed on the inclined table and against the ledge set in a position appropriate to the size of the block. Thus supported the block was presented to the circular saw which cut away the angle required.
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Corner Saw, 1804.
A wooden block with the corners cut of.
Shaping engine, 1804. This machine cuts the faces and sides of the block shells, creating a more rounded shape. Ten shells are mounted at a time on a drum that rotates past the cutter. After cutting one side the shells are accurately rotated through 90o, presenting the next side to be cut.
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Shaping engine, 1804.
A wooden block with a more rounded shape.
Scoring engine, 1804. This forms a groove locating the fixed rope running around the outside of the pulley block to hold it in its required position during use. The shells are then removed to receive some light finishing by hand.
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Scoring engine, 1804.
A wooden block with long grooves round the edges.
Sheave-makingSteps in the production of the sheave:
Circular saw: This cuts a segment from a log of Lignum Vitae - a resilient dense hardwood from the West Indies or South America - to form the sheave.
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Circular saw, 1804.
A disc from a log.
Crown saw: The wood segment for the sheave cut by the circular saw is trimmed by this machine into a circular disc of the required diameter while a hole is simultaneously drilled through the middle.
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Crown saw, 1804.
A trimmed circular disc with a hole in the middle.
Coaking engine: This makes three recesses in the outside edges of the hole provided by the rounding saw in order to locate and secure the ears of the coak - a bronze fitting which acts as the sheaves' bearing.
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Coaking engine, 1804.
An animation showing a recess around a hole in the middle of a disc and a bronze coak slinding into the hole.
Riveting hammer: This rivetted pins through the holes in the coak made by the drilling machine, holding the coak in position.
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Riveting hammer, 1803. This image is reproduced from Rees' Cyclopedia.
An animation showing three pins going into the holes in the coak.
Broaching machine: This bored out the inside of the coak making it smooth, cylindrical and concentric with the sheave rim.
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Broaching machine: This image is reproduced from Marc Brunel's sketchbook.
A disc with a smooth hole.
Face-turning lathe: The lathe turned the faces of the sheave until they were smooth and cut a groove in the edge for the rope.
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Face-turning lathe, 1803. This image is reproduced from Rees' Cyclopedia.
A smooth disc with a groove round the edge.
Putting the block together
Two sheaves are places inside the two slots in the shell. The axel is put through the holes in the centre of the shell and the two sheaves. Now we have a finished block.
From the moment it took over block production in 1805, the Portsmouth blockmaking machinery caught the public imagination. Described in Rees' Cyclopedia in 1819 as 'the most ingenious and complete system of machinery for forming articles from wood, of any this kingdom can produce', it was a magnet for sightseers at Portsmouth - so much so, that in 1805 Marc Brunel urged Bentham to erect a fence around the block mill to keep visitors out.
But for all the public admiration it received, the mass-production principles the machinery embodied were not widely applied in British manufacturing until the 1850s.
Interestingly, Samuel Bentham (who sponsored the innovations in blockmaking) was the brother of Jeremy Bentham, the utilitarian philosopher.
Some see in the blockmaking machines a unique link between enlightenment belief in rationalism and emerging systems of mass production.
Images with this text:
Bust of Marc Brunel by the sculptor Sir Francis Chantrey. Such were Brunel's engineering achievements, including the Portsmouth blockmaking machinery, that he joined the pantheon of innovators immortalised by Chantrey in his work.
Window commemorating Henry Maudslay at Greenwich town hall, 1995. Maudslay's work on the Portsmouth blockmaking machinery, along with his other engineering achievements, assured him a place in the very top rank of engineers.

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