Forgotten History – Mass Production and the Portsmouth Block Mills

Who invented  mass production? Surely it was Henry Ford in 1910 or thereabouts? Didn’t he invent the production line to produce the Model T motor car?

Well, no he did not.

A Frenchman called Marc Isambard Brunel [the father of Isambard Kingdom Brunel] has a better claim to being the father of the production line because he created such a line in the Naval Dockyard at Portsmouth at least a century before Ford.

The Royal Navy needed about 100,000 pulley blocks of various sizes each year.  They were  used in a variety of ways including hoisting sales and handling guns. A 74 gun  ship might use a thousand of various sizes.

These used to be made according to the ‘craftsman’ method of working with one person carrying out all the operations needed to produce a block. This was expensive and the quality  unreliable. Incidentally, Ford used the craftsman model to assemble his first cars. It was only later that he introduced production lines.

In 1795,  Sir Samuel Bentham was appointed  Inspector General of Naval Works with the task of modernising the Portsmouth Dockyard; including introducing steam power and mechanising the production processes in the dockyard. He was very receptive to innovations.

In 1802 Brunel put forward a system of making blocks using machinery he had designed. Bentham appreciated the superiority of Brunel’s system and in August 1802 he was authorised by the Admiralty to proceed.

Bentham and Brunel set up the Portsmouth Block Mills and commissioned Henry Maudslay to make its machines.  Their idea was that there would be a line of general purpose [e.g. saws] and specialised machines and a block would pass down the line with one operation being carried out at each stage.  Unskilled labour would be used. There is evidence that Maudslay made a significant contribution to the design of the machines. Brunel’s first plans show wooden framed machines and bear little resemblance to the final designs.

The Portsmouth Block Mills today

Some of the machines used are listed below.

  • Pendulum saw: This machine cut the wood for making the block shells from an elm log.
  • Boring machine: This machine bored out the shells One drill bored the hole for the pivot pin that passes through the shell on which the sheave runs. The other bored a larger initial hole at right angles that will be elongated by the mortising machine chisel to form the slot for the sheave.
  • Mortising machine:  The mortising machine chiseled out the slot in which the sheave  turned.
  • Corner Saw: The circular saw  cut away the angle required.
  • Shaping engine: . This machine cut the faces and sides of the block shells, creating a more rounded shape. Ten shells were mounted  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.
  • Scoring engine:  This formed 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 were then removed to receive some light finishing by hand.
  • Circular saw: This cut a segment from a log of Lignum Vitae – a resilient dense hardwood from the West Indies or South America – to form the sheave.
  • Crown saw: The wood segment for the sheave cut by the circular saw was trimmed by this machine into a circular disc of the required diameter while a hole was simultaneously drilled through the middle.
  • Coaking engine: This maked 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 acted as the sheaves bearing.
  • Riveting hammer: This riveted pins through the holes in the coak made by the drilling machine, holding the coak in position.
  • Broaching machine: This bored out the inside of the coak making it smooth, cylindrical and concentric with the sheave rim.
  • 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.

The specialised machines were almost entirely hand-made, the only machine tools used used by Maudsley being lathes to machine circular parts, and drilling machines for boring small holes. At that time there were no milling, planing or shaping machines, and all flat surfaces were made by hand chipping, filing and scraping.  Each nut was made to fit its matching bolt and were numbered to ensure they were replaced correctly. The materials used were cast and wrought iron, brass and gun-metal. The use of metal throughout their construction greatly improved their rigidity and accuracy which became the standard for later machine tool manufacture.

There were three series of block-making machines, each designed to make a range of block sizes. The production line  for medium blocks, was installed in January 1803. The line for  smaller blocks in May 1803, and the third line for large blocks in March 1805.  A total of 45 machines were installed. Machinery was modified and different techniques tried until  in September 1807 the plant was felt able to provide all the block needed by the Navy. By 1808 the forty-five machines were turning out 130,000 pulley blocks per year and ten unskilled men were able to equal the output of 100 skilled men working according to the craftsman model. The capital cost of the project was recovered in three years. Brunel was paid a sum equal to the annual saving; in 1810 he calculated this at £21174 12s 10d.

When the public learned of the Portsmouth block making mill it became a tourist attraction and a fence had to be erected to keep people out. Despite the public attention its mass-production principles were not widely applied in British manufacturing until the 1850s.  Given that the productivity gains were so dramatic it is hard to understand why the lessons of the Portsmouth Block Mills  were not applied elsewhere.

Block-making ceased  in 1965.

I visited the dockyard museum some years ago and it had an exhibition explaining what Bentham, Brunel and Maudlsay had achieved. They had some of  original machinery.  The Science Museum in London also has some of the machines in their Makers of the Modern World Gallery. Photographs of these machines are in this post.

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1 Comment

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One response to “Forgotten History – Mass Production and the Portsmouth Block Mills

  1. Mel Earley

    I served for 4 months in the Portsmouth Block Mills in 1963 as part of my 5 year Shipwright apprenticeship. At this time there were only 3 original block makers surviving all due for retirement. I was not allowed to use any machinery then because I was under 18 years old. My job was to shape the blocks with a spokes shave, rivet them together and make final assembly. After serving my apprenticeship I stayed at my trade until 1969 when I retrained in another field. The apprenticeship in Portsmouth Dockyard was second to none and I really enjoyed my time there.

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