British mechanical engineer Henry Maudslay (1771-1831), known as the father of the machine-tool industry, laid an important foundation for the Industrial Revolution by improving interchangeability and precision in tool-making. Maudslay also made many other advancements in engine design.

Maudslay was born in Woolwich, Kent, in the southeastern part of England, on August 22, 1771. His father was a mechanic at the Royal Arsenal in Woolwich, and by the age of 12 Maudslay was also working at the arsenal as a "powder monkey." His task was to fill cartridges with gunpowder. In just two years, he was promoted to the joiner's shop and then apprenticed as blacksmith in the metalworking shop.

At the age of 18, Maudslay, who had developed extraordinary skills, left the arsenal to work with Joseph Bramah, a pioneer in hydraulics and locksmith work. Bramah, the inventor of the first unpickable lock, soon noted Maudslay's talent and within a short time promoted him to foreman. Maudslay worked with Bramah from 1789 to 1798, then left after a dispute over wages to form his own business.

Building Blocks

At 27, Maudslay opened his first engineering shop off Oxford Street in London, relocating four years later to a facility on Margaret Street. His first big job was a commission from Marc Isambard Brunel and Samuel Bentham for the production of 43 machines that could manufacture wooden blocks, or pulleys, for the British Admiralty to use at the Royal Dockyards in Portsmouth. The block-making machinery consisted of metal tooling machines that cut wood and were organized in an assembly line fashion. Reciprocating saws, circular saws, boring tools, milling machines, and lathes, run on power from a 30-horsepower steam engine, were used to build blocks in three sizes.

Built at Portsmouth over almost six years, the machine factory produced more than 130,000 new blocks every year. Ten unskilled workers could operate the machinery and accomplish the work done by 110 skilled workers prior to mechanization. Some of the blocks produced by the machinery invented by Maudslay were used in Portsmouth until the 1940s.

Developed Screw-Cutting Lathe

Maudslay's most influential invention came early in his career. In 1799 and 1800, he developed a screw-cutting lathe. The machine, which created uniformity in screws, was a revolutionary development necessary for the Industrial Revolution. Although others, including Jesse Ramsden and David Wilkinson, had constructed lathes prior to Maudslay, Maudslay's instrument offered improvements in durability, functionality, and precision by including a slide-rest, lead-screw, changeable gears, and an all-metal design. According to Great Engineers and Pioneers in Technology, "Maudslay's screw-cutting lathe consisted of a spindle, on which the work was mounted, connected by a series of gears to the lead screw, which propelled the sliding tool carriage." A knife-edged steel instrument that could be set at any angle determined the pitch of the screw or the angle at which the grooves were cut. A softer metal bar was revolved while being cut by the sliding tool bar that held the cutting tool. Because the lathe operated on a spindle, it could advance at a constant rate, thus creating grooves that were uniform in depth, angle, and spacing.

Before the development of Maudslay's lathe, which became the first to be used widely in manufacturing, each screw or bolt was a unique item that had to be matched with a unique nut. Every bolt and every nut had to be marked as a matching pair. The process of matching bolts and nuts in the construction of complicated machinery proved to be time-consuming, frustrating, and expensive. Any machine that needed repair and thus required disassembly could easily become a nightmare of mismatched screws and nuts. In his autobiography, James Nasmyth, a talented engineer who worked from 1828 to 1830 as an assistant in Maudslay's shop, noted: "None but those who lived in the comparatively early days of machine manufacture can form an adequate idea of the annoyance, delay, and cost of this utter want of system, or can appreciate the vast services rendered to mechanical engineering by Mr. Maudslay, who was the first to introduce the practical measures necessary for its remedy. In his system of screw-cutting machinery, and in his taps and dies, and screw-tackle generally, he set the example, and in fact laid the foundation, of all that has since been done in this most essential branch of machine construction."

To prove the perfection of his device, Maudslay used his screw-cutting lathe to create a screw that was five feet in length and two inches in diameter, with 50 thread cuts per inch. The accompanying nut was 12 inches long and contained 600 thread cuts. Although Maudslay's early version of his lathe required a machinist to take the lathe apart to change settings, later he added design improvements that allowed the operator to alter settings by simply switching removable gears. Maudslay's original lathe is housed at the Science Museum in London.

The lathe is one of the oldest machine tools, and its use went back many centuries. Early lathes were all used to cut and form wood. Maudslay's mechanical advances were important because he developed a machine that could be used to build other machines. Because his lathe could cut and form tool steel, engineers who later improved upon his work were able to supply greatly needed consistency and precision in a wide array of industrial machine parts. Those who specialized in precision were also aided by Maudslay's advancements, including clockmakers, builders of scientific instruments such as telescopes and navigational equipment, and gunmakers.

Perfection and Precision

Maudslay, not surprisingly, was a perfectionist. He maintained careful order in his manufacturing shop, with tools, prototypes, and inventions neatly arranged. With his business growing and gaining notice, he eventually employed several hundred workers at his factory in Lambeth. Each craftsperson was supplied with standard plane surfaces, taps, and dies so that all work could be checked for accuracy and consistency. In his desire to measure his perfection, Maudslay made another advancement in mechanical science by inventing a bench micrometer with an accuracy range to 0.0001 inches, or 0.0025 millimeters.

Considered a brilliant and kind man, Maudslay took note of those with particular talent who entered his workforce. Several important mechanical engineers apprenticed under and worked with Maudslay, including Richard Roberts, Joseph Clement, James Nasmyth, and Sir Joseph Whitworth. Joshua Field, a noted designer of marine steam engines, eventually became a partner in the business. Along with Maudslay's two sons, Thomas Henry and Joseph, the business became known as Maudslay, Sons, and Field.

Engine Work

Deeply interested in engines himself, Maudslay worked closely with Field in engine design. In 1807 he was awarded a patent on the first table engine, which became a main source for compact power for years. The table engine replaced the traditional walking beam and became widely used in machine shops and aboard ships.

With the assistance of Field, Maudslay manufactured marine steam engines. The initial engines were small, with only 17-horsepower capacity, but later Maudslay's factory produced engines as large as 56 horsepower. Late in his life, Maudslay directed his craftsmen to construct two 200-horsepower engines. Both his sons and Field were quite skeptical of the directive, considering the endeavor too expensive when no customer was at hand to buy them. Nonetheless, the engines were built, and the Royal Admiralty was pursued to purchase them for the steamship, the Dee, then under construction. Maudslay was so pleased with the outcome that he commissioned Nasmyth, who had the skills of an artist, to draft a memorial portrait drawing. Seven years after Maudslay's death, his firm, which was continued for over a quarter of a century by his sons, built a 750-horsepower steam engine to power the transatlantic ship, the Great Western.

Continuous Curiosity

Besides machine tooling and steam engines, Maudslay had a vast creative interest spanning many other areas. According to Nasmyth, "Mr. Maudslay was a man of a wide range of mechanical abilities. He was always ready to enter upon any new work requiring the exercise of special skill. It did not matter whether it was machine tools, engraving dies, block machinery, or astronomical instruments." He held patents on numerous inventions, including a method of printing calico, a process of differential motion for raising weights and turning lathes (with Bryan Donkin), a process for water purification (with Robert Dickinson), and methods of removing the salt and regulating the water flow of marine boilers (with Fields).

During the final part of his life, Maudslay developed a strong interest in designing a powerful telescope after a trip to Germany offered him the chance to visit the Berlin Observatory and see powerful images of Jupiter, Saturn, and the moon. At Lambeth, he began to study the problems and difficulties in distortion associated with glass telescopes. His desire was to build a grand telescope no less than 24 inches in diameter. However, in January 1831, after visiting a sick friend in Boulogne, France, he caught a severe cold during the trip back across the English Channel. Upon arriving home, he remained bedridden for almost a month and never recovered his health. He died on February 14, 1831. Following his written instructions, he was buried in a cast iron tomb of his own design in a Woolwich churchyard. In memory of his great contributions, a statue was erected near the ferry dock in Woolwich.

Along with the many toolmaking contributions Maudslay offered to the development of mechanical science, he also influenced his generation and those that followed with his unrelenting expectations of precision and accuracy. Clearly he benefited from the work of those before him, but in many ways Maudslay's genius marked a new direction in the industrial world that opened the doors to innumerable possibilities.

Further Reading

• The Cambridge Biographical Encyclopedia, 2nd edition, edited by David Crystal, Cambridge University Press, 1998.
• Chambers Biographical Dictionary, 6th edition, edited by Melanie Parry, Chambers, 1997.
• Daintith, John; Sarah Mitchell; and Elizabeth Tootill, A Biographical Encyclopedia of Scientists, Volume 2, Facts on File, 1981.
• Great Engineers and Pioneers in Technology, Volume 1, edited by Roland Turner and Steven L. Goulden, St. Martin's Press, 1981.
• Williams, Trevor I., A Biographical Dictionary of Scientists, 3rd edition, Adam and Charles Black, 1982.
• "Henry Maudslay," Merriam-Webster's Biographical Dictionary, http://www.galenet.com (February 7, 2001).
• "Henry Maudslay," World of Invention, http://www.galenet.com (February 7, 2001).
• Nasmyth, James, The Autobiography of James Nasmyth, http://www.naesmyth.com/bio (February 7, 2001).