1911 Encyclopædia Britannica/Whitworth, Sir Joseph

WHITWORTH, SIR JOSEPH, Bart. (1803-1887), English engineer, was born at Stockport, near Manchester, on the 21st of December 1803. On leaving school at the age of fourteen, he was placed with an uncle who was a cotton-spinner, with the view of becoming a partner in the business; but his mechanical tastes were not satisfied with this occupation, and in about four years he gave it up. He then spent some time with various machine manufacturers in the neighbourhood of Manchester, and in 1825 moved to London, where he gained more experience in machine shops, including those of Henry Maudslay. In 1833 he returned to Manchester and started in business as a toolmaker. In 1840 he attended the meeting of the British Association at Glasgow, and read a paper on the preparation and value of true planes, describing the method which he had successfully used for making them when at Maudslay's, and which depended on the principle that if any two of three surfaces exactly fit each other, all three must be true planes. The accuracy of workmanship thus indicated was far ahead of what was contemplated at the time as possible in mechanical engineering, but Whitworth not only proved that it could be attained in practice, but also showed how it could be measured. He found that if two true planes were arranged parallel to each other, an exceedingly small motion towards or from each other was sufficient to determine whether an object placed between them was held firmly or allowed to drop, and by mounting one of the planes on a screwed shaft provided with a comparatively large wheel bearing a scale on its periphery, he was able to obtain a very exact measurement of the amount, however minute, by which the distance between the planes was altered, by observing through what angular distance the wheel had been turned. In 1841, in a paper read before the Institution of Civil Engineers, he urged the necessity for the adoption of a uniform system of screw threads in place of the various heterogeneous pitches then employed. His system of standard gauges was also widely adopted. The principles of exact measurement and workmanship which he advocated were strictly observed in his own manufactory, with the result that in the Exhibition of 1851 he had a show of machine tools which were far ahead of those of any competitor. It was doubtless this superiority in machine construction that caused the government three years later to request him to design, and estimate for making, the machinery for producing rifled muskets at the new factory at Enfield. He did not see his way to agree to the proposition in this form, but it was ultimately settled that he should undertake the machinery for the barrels only. Finding that there was no established practice to guide him, he began a series of experiments to determine the best principles for the manufacture of rifle barrels and projectiles. He ultimately arrived at a weapon in which the necessary rotation of the projectile was obtained, not by means of grooving, but by making the barrel polygonal in form, with gently rounded angles, the bullets also being polygonal and thus travelling on broad bearing-surfaces along the rotating polygon. The projectile he favoured was 3 to 3½ calibres in length, and the bore he fixed on was 0.45 in., which was at first looked upon as too small. It is reported that at the trial in 1857 weapons made according to these principles excelled the Enfield weapons in accuracy of fire, penetration and range to a degree “which hardly leaves room for comparison.” He also constructed heavy guns on the same lines; these were tried in competition with Armstrong's ordnance in 1864 and 1865, and in their inventor's opinion gave the better results, but they were not adopted by the government. In constructing them Whitworth experienced difficulty in getting large steel castings of suitable soundness and ductility, and thus was led about 1870 to devise his compressed steel process, in which the metal is subjected to high pressure while still in the fluid state, and is afterwards forged in hydraulic presses, not by hammers. In 186S he founded the Whitworth scholarships, setting aside an annual sum of £3000 to be given for “intelligence and proficiency in the theory and practice of mechanics and its cognate sciences,” and in the following year he was created a baronet. He died at Monte Carlo, whither he had gone for the sake of his health, on the 22nd of January 1887. In addition to handing over £100,000 to the Science and Art Department for the permanent endowment of the thirty Whitworth scholarships, his residuary legatees, in pursuance of what they knew to be his intentions, expended over half a million on charitable and educational objects, mainly in Manchester and the neighbourhood.