Portsmouth Block Mills

The Portsmouth Block Mills form part of the Portsmouth Dockyard at Portsmouth, Hampshire, England, and were built during the Napoleonic Wars to supply the British Royal Navy with pulley blocks. They started the age of mass-production using all-metal machine tools and are regarded as one of the seminal buildings of the British Industrial Revolution. They are also the site of the first stationary steam engines used by the Admiralty.

Significant features

These machines utilised several features for the first time which have since become commonplace in machine design.

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• The boring operation indented gauging points in the wooden blocks which the clamps of the later machines used to locate the blocks precicely. This meant that positioning of the block in later processes ensured accurate location in relation to the tool working on it.
• Several of the machines had cone clutches.
• Brunel used detachable tool bits held in tool holders very similar to those use now on general purpose lathes.
• Expanding collet chucks were used to locate the sheaves by gripping the internal bore, during certain operations.
• Two-jaw gripping chucks were used on some machines.These were the precursoir of the three-jaw chucks used on lathes today.
• The morticing machines could be set so the operation was stopped automatically once the operation finished.
• Interchangeability of the sheaves and pins was possible, since they were not married to a particular shell.
• The work-flow is perhaps best described as batch production, because of the range of block sizes demanded. But it was basically a production-line system, nevertheless. This methods of working did not catch on in general manufacturing in Britain for many decades, and when it did it was imported from America.
• The entire system was designed to be worked by labourers and not apprentice-trained craftsmen. Each man was trained to operate two or more machines and could be moved round the plant as required.