The family originally came from Whitfield, near Glossop.  John Dewsnap (1757-1844) was baptised at Sheffield, the son of Joshua (a cutler) and his wife, Sarah.  His brother was Joshua Dewsnap, a silver cutler at Trinity Street.  John was apprenticed to his father in 1774 and became a Freeman in 1779.  In 1787, he was listed as a maker of silver-plated table knives at Queen Street (whose trade mark was ‘FABRE’).  By 1797, he had relocated to Arundel Street, where he was silver cap and ferrule maker and haft presser.  In 1803, John registered a silver mark in Arundel Street as a plate worker.  He described himself as a merchant in Arundel Street by 1816.  In 1828, John Dewsnap & Son was listed as a merchant, Broomgrove.  John’s son, by his wife Bridget, was Thomas Dewsnap (bapt.1785-1864), who was Master Cutler in 1823.  

In 1841, John and Thomas lived at Clarke House, Clarkehouse Road.  John died on 23 December 1844, aged 87, and was buried at St George’s churchyard, Portobello.  By 1851, Thomas had retired from business and had in-vested in property and houses.  In his later years he moved to Grove Hall, Stockwell Road, Lambeth.  He died there on 16 May 1864, aged 80.  Apparently a bachelor, he willed his estate (worth under £12,000) to various charities, through his executors: Henry Elliot Hoole, George Norton, and Richard Vincent Ambler.  The will was contested by various kin, but validated in 1867, though the trustees later misappropriated most of the money (Sheffield Independent, 13 January 1866, 7 March 1891).