A pioneer of law and order in the mechanical world, Sir Joseph Whitworth raised accuracy in engineering to a new standard. His name is universally associated with the Whitworth screw thread, and he made many other striking contributions to engineering science
A much-prized distinction peculiar to the engineer is the right to append the letters “Wh.Sc” to his name. This means that a Whitworth Scholarship has been gained by the man thus distinguished and indicates that he has had a thoroughly sound professional training. The scholarships were founded in 1869, by Sir Joseph Whitworth, who moreover left £100,000 to endow them so that the artisan and the student might be encouraged to pursue an organized engineering education. But the Whitworth Scholar is not the only reminder we have of this intensely practical engineer, for there can be few who have not heard of the “Whitworth thread”.
Joseph Whitworth, born in 1803 at Stockport, Cheshire, was the son of a schoolmaster and had a good education, though it ended at the age of 14, when he went to an uncle to learn the business of cotton spinning. Having found this occupation not to his taste, he ran away to Manchester in 1821 and started work at the bench of an engineer’s shop there. Four years in Manchester were enough to show him that mechanical development was gravely handicapped by the want of reliable tools.
London was then renowned for the excellence of its workmanship in this direction and thither he went, to work for a time with Henry Maudslay, as did James Nasmyth and some other young engineers afterwards to become famous. It was while Whitworth was at Maudslay’s that he worked out his first invention - the true surface plate, an instrument as vital to the engineer as the straight edge and square. The production of a true surface seems a simple matter but at that time it was one of considerable difficulty, and required an enormous amount of skill and patience.
At the age of 30 Whitworth returned to Manchester, setting up as a tool maker. From then until 1854 he designed and perfected a series of machine tools which found their way into the workshops of the world. When he started work every man had his own standards and his own ideas of how they should be worked to. Whitworth was the pioneer of law and order in the mechanical world. His measuring machine was an immense improvement on anything that had gone before. Most mechanics can detect by touch differences in size which are too minute to be read visually on an ordinary scale. Whitworth made a machine using this sense of touch and, by magnifying the readings by accurate screws and worm gear, made it possible to distinguish differences in size of as little as one-millionth part of an inch.
Though this extreme degree of accuracy was not really called for, the measuring machine was useful for less exacting degrees of precision. Its utility was, however, not nearly such a boon to engineering as was the introduction of the Whitworth thread. Before this event it would be only by the merest chance that an inch nut, say, from one firm would go on to an inch bolt from another firm. Whitworth investigated the subject of screw threads with characteristic thoroughness and finally decided on a constant proportion between the depth of a thread and the pitch whatever its diameter might be. This was a real advance and in 1842 the Whitworth thread was formally adopted by the Royal Dockyard, Woolwich. From this start the system spread rapidly, penetrating many foreign countries, and it is still perhaps the most important of the many engineering standards.
Whitworth concerned himself with tools exclusively up to 1854, but in that year, as he held the highest position as a maker of accurate machinery in Great Britain, he was called upon by the Government to set up factories for the manufacture of the Enfield rifle. Whitworth would not accept the task without finding out what was the reason for the want of uniformity in performance of this rifle.
Having set up a range and carried out numerous experiments, he arrived at a solution and produced a rifle which, in 1857, proved much superior to the Enfield. But he met with nothing but discouragement from official quarters, and the same thing happened with regard to Whitworth’s valuable work in connexion with heavy ordnance.
A notable contribution to engineering science was Whitworth’s development of compressed steel, that is, subjecting it to heavy pressure while it was still molten, with the object of getting rid of the sponginess which was then the bane of large steel castings. Other investigators had, however, been at work on this problem before him. Whitworth was a good business man and made large profits from his work as well as from training a number of good engineers.
In addition to his generosity in the matter of the scholarships, Whitworth bequeathed £500,000 for other educational and charitable objects. He was created a baronet in 1869, and had been elected a Fellow of the Royal Society in 1857, Dublin and Oxford Universities conferring Doctorates on him in the same year. He was honoured by Napoleon III in 1869.
Whitworth’s later years were spent in such pursuits as the breeding of shorthorn cattle, landscape gardening and so forth, in which he exercised the same thoroughness as he had done in his profession. These years were mainly spent at Stancliffe, near Matlock, Derbyshire. He died at Monte Carlo in 1887, having made many notable contributions to engineering history.