Exactly – How Precision Engineers Created the Modern World by Simon Winchester

Publisher:        William Collins

Published:       2018

ISBN-10:         0008241767

ISBN-13:         9780008241766

Pages:             416 (2018 hardback edition)

Words:            152,000 approx.

Simon Winchester OBE is a British-born journalist with a long record of covering key news events (including Bloody Sunday and Watergate) and a series of well-researched factual books behind him.  His previous books include Krakatoa and The Surgeon of Crowthorne (about contributions made to the original Oxford English Dictionary by an inmate at Broadmoor Hospital).

This book describes the history of mechanical precision, starting from the application of John ‘iron mad’ Wilkinson’s canon-boring technique to the cylinders for James Watt’s steam engines.  The account does not restrict itself to mechanical precision for purely mechanical systems.  Later chapters cover the techniques used to achieve the extreme and finely detailed dimensional accuracy needed for the manufacture of modern digital chips, and the issues of optical precision which confronted the initially ill-fated Hubble Space Telescope. 

An early chapter explains that precision manufacture is essential to make mechanical parts freely interchangeable, even in something as simple as a musket. This point is made using the experiences of a fictitious American soldier fighting the British in the war of 1812, who’s contribution is slight because his musket has a broken trigger which cannot be replaced (because a new trigger must be made by a blacksmith) for some days. 

The story continues by way of Joseph Bramah’s challenge to all-comers to attempt to pick his allegedly unpickable lock.  The contributions made by Bramah’s one-time apprentice Henry Maudslay (the bench micrometer and the screw-cutting lathe) are covered, together with Maudslay’s work on Marc Isambard Brunel’s system for mass-producing pulley blocks for the Royal Navy – possibly the first instance of automated mass production.  Much emphasis is put on the idea of a machine tool as a machine which makes other machines and as an idea which is essential to mass production and to reproducible mechanical precision.

The different manufacturing philosophies of Rolls-Royce and Henry Ford are discussed by way of some lengthy anecdotes about the author’s experiences of driving Roll-Royces during his days as a journalist.  It becomes clear from this part of the book that the two companies used precision in quite different ways; in the former case to ensure ultimate quality, and in the latter to ensure that each part delivered to the production line would fit exactly as required without ever any need for fettling or adjustment.

The shear spectacle of the Great Exhibition of 1851 is described, together with the relevance of the new ideas of precision to the prestigious products and inventions displayed there.  The slightly-scary sight of massive steam-driven machinery at the Exhibition is described – a spectacle made more alarming by the fact that the boilers providing steam to those exhibits were housed outside the Crystal Palace itself.

Turning to precision in optics, the author again uses some of his own experiences of high-quality equipment to explain just how the development of modern cameras occurred.  This account goes right back to Niepce in the 1820s with his hours-long exposures and includes clear explanations of the advantages of multi-element and aspheric lenses. 

Some almost unbelievable statistics relating to the manufacture of chips are given.  One of the most amazing of these is an estimate of the number of transistors in the world – thought to be more than the number of leaves on all the world’s trees.  Another is the confident prediction (attributed to an Intel executive) that by 2020 there will be a chip containing more transistors than there are neurons in a human brain.  The chapter about chip manufacture also contains a section on the LIGO gravitational wave observatory, described early in the book as the most precise instrument yet made by man.  It is explained that the successful operation of that instrument depends on the detection of changes in the length of a kilometres-long tunnel which are small compared to the diameter of a proton.

Finally (if one ignores the Afterword), there is a chapter about the respectful attitudes in Japanese culture to extreme precision, on the one hand, and traditional craft modes of production on the other.  The author describes a visit to the Seiko factory, where both types of attitude can be seen side-by-side.  There, quartz watches are being made by the thousands per day in one part of the building while mechanical watches are being made by a small team of craftsmen. There is no hint that anyone in Japan would see any incongruity.

There is a fascinating account in the Afterword of the development of the modern system of measurement units (the Systeme International), explaining the forces which have driven that system to eventually adopt standards based on universally-available references sources (such as the wavelengths of particular spectral lines emitted by particular atoms) provided by nature herself.

This is an entertaining account of the development of mechanical precision with a clear explanation of the historical drivers responsible.  Apt and entertaining illustrations of some of the key steps in the process are given, in several cases based on the author’s own experiences.