section_path: Important technological developments/Machine tools
section_name: Machine tools
paragraph_text: Machine tools
  
  Pre-industrial machinery was built by various craftsmen — millwrights built watermills and windmills; carpenters made wooden framing; and smiths and turners made metal parts. Wooden components had the disadvantage of changing dimensions with temperature and humidity, and the various joints tended to rack (work loose) over time. As the Industrial Revolution progressed, machines with metal parts and frames became more common. Other important uses of metal parts were in firearms and threaded fasteners, such as machine screws, bolts, and nuts. There was also the need for precision in making parts. Precision would allow better working machinery, interchangeability of parts, and standardization of threaded fasteners.
  
  The demand for metal parts led to the development of several machine tools. They have their origins in the tools developed in the 18th century by makers of clocks and watches and scientific instrument makers to enable them to batch-produce small mechanisms. Before the advent of machine tools, metal was worked manually using the basic hand tools of hammers, files, scrapers, saws, and chisels. Consequently, the use of metal machine parts was kept to a minimum. Hand methods of production were laborious and costly, and precision was difficult to achieve.
  
  The first large precision machine tool was the cylinder boring machine invented by John Wilkinson in 1774. It was designed to bore the large cylinders on early steam engines. Wilkinson's machine was the first to use the principle of line-boring, where the tool is supported on both ends, unlike earlier designs used for boring cannon that relied on a less stable cantilevered boring bar.
  
  The planing machine, the milling machine and the shaping machine were developed in the early decades of the 19th century. Although the milling machine was invented at this time, it was not developed as a serious workshop tool until somewhat later in the 19th century. James Fox of Derby and Matthew Murray of Leeds were manufacturers of machine tools who found success in exporting from England and are also notable for having developed the planer around the same time as Richard Roberts of Manchester.
  
  Henry Maudslay, who trained a school of machine tool makers early in the 19th century, was a mechanic with superior ability who had been employed at the Royal Arsenal, Woolwich. He worked as an apprentice at the Royal Arsenal under Jan Verbruggen. In 1774 Verbruggen had installed a horizontal boring machine which was the first industrial size lathe in the UK. Maudslay was hired away by Joseph Bramah for the production of high-security metal locks that required precision craftsmanship. Bramah patented a lathe that had similarities to the slide rest lathe. Maudslay perfected the slide rest lathe, which could cut machine screws of different thread pitches by using changeable gears between the spindle and the lead screw. Before its invention, screws could not be cut to any precision using various earlier lathe designs, some of which copied from a template. The slide rest lathe was called one of history's most important inventions. Although it was not entirely Maudslay's idea, he was the first person to build a functional lathe using a combination of known innovations of the lead screw, slide rest, and change gears.
  
  Maudslay left Bramah's employment and set up his own shop. He was engaged to build the machinery for making ships' pulley blocks for the Royal Navy in the Portsmouth Block Mills. These machines were all-metal and were the first machines for mass production and making components with a degree of interchangeability. The lessons Maudslay learned about the need for stability and precision he adapted to the development of machine tools, and in his workshops, he trained a generation of men to build on his work, such as Richard Roberts, Joseph Clement and Joseph Whitworth.
  
  The techniques to make mass-produced metal parts of sufficient precision to be interchangeable is largely attributed to a program of the U.S. Department of War which perfected interchangeable parts for firearms in the early 19th century. In the half-century following the invention of the fundamental machine tools, the machine industry became the largest industrial sector of the U.S. economy, by value added.