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of Odlham, maker of textile machinery
The Platt family began to manufacture machinery for the woollen industry from a small workshop at Nicker Brow, Dobcross, Saddleworth, Lancashire, before moving to Oldham.
By 1821 Henry Platt had established himself in Oldham as a manufacturer of cotton spinning machinery, the formation of the company.
1822 Henry Platt entered a partnership with Elijah Hibbert as Hibbert and Platt and later as Hibbert, Platt and Sons which developed from an assembler of parts manufactured by others, to a fully integrated manufacturer in its own right.
1829–30 Opened Hartford works at Greenacres Moor
1834 William Richardson started work for the company
1837 John Platt became a partner in the company
1840 Employing 200 to 300 men.
1843 'FALL OF A BEAM IN A FOUNDRY.-An alarming and serious accident occurred at the iron foundry of Messrs. Hibbert and Platt, Greenacres Moor, on Thursday evening. The iron beam of one of the foundry roofs gave way, and fell down with a tremendous crash, when several of the workmen were more or less injured by the fall of materials, and one was considered in extreme danger, but is now in course of recovery. It is wonderful that such an affair should have occurred without any loss of life.'
1845 Opened the Hartford New works at Oldham's new railhead
1846 John Platt became the senior partner in the firm after the death of his father in 1842, of his elder brother Joseph (1815–1845), and of Elijah Hibbert in 1846
1851 Employing 1,070 men and 239 boys. 
1851 Award at the 1851 Great Exhibition. See details at 1851 Great Exhibition: Reports of the Juries: Class VI.