centreless precision grinding

n (BrE)

MECH, MECH ENG rectificado de precisión sin puntos m

(AmE) see centreless precision grinding BrE

SUBJECT AREA: Mechanical, pneumatic and hydraulic engineering

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Hans Renold was educated at the cantonal school of his native town and at the Polytechnic in Zurich. He worked in two or three small workshops during the polytechnic vacations and served an apprenticeship of eighteen months in an engineering works at Neuchâtel, Switzerland. After a short period of military service he found employment as a draughtsman in an engineering firm at Saint-Denis, near Paris, from 1871 to 1873. In 1873 Renold moved first to London and then to Manchester as a draughtsman and inspector with a firm of machinery exporters. From 1877 to 1879 he was a partner in his own firm of machine exporters. In 1879 he purchased a small firm in Salford making chain for the textile industry. At about this time J.K.Starley introduced the "safety" bicycle, which, however, lacked a satisfactory drive chain. Renold met this need with the invention of the bush roller chain, which he patented in 1880. The new chain formed the basis of the precision chain industry: the business expanded and new premises were acquired in Brook Street, Manchester, in 1881. In the same year Renold became a naturalized British subject.

Continued expansion of the business necessitated the opening of a new factory in Brook Street in 1889. The factory was extended in 1895, but by 1906 more accommodation was needed and a site of 11 ½ acres was acquired in the Manchester suburb of Burnage: the move to the new building was finally completed in 1914. Over the years, further developments in the techniques of chain manufacture were made, including the invention in 1895 of the inverted tooth or silent chain. Renold made his first visit to America in 1891 to study machine-tool developments and designed for his own works special machine tools, including centreless grinding machines for dealing with wire rods up to 10 ft (3 m) in length.

The business was established as a private limited company in 1903 and merged with the Coventry Chain Company Ltd in 1930. Good industrial relations were always of concern to Renold and he established a 48-hour week as early as 1896, in which year a works canteen was opened. Joint consultation with shop stewards date2 from 1917. Renold was elected a Member of the Institution of Mechanical Engineers in 1902 and in 1917 he was made a magistrate of the City of Manchester.

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