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Campbells and Hunter of Dolphin Foundry, Leeds were makers of machine tools.
Previously Thomas Campbell, Son and Co were at Dolphin Foundry in East Street, Leeds.
1874 Patent application by Thomas Campbell, John William Campbell, and John Hunter, all of the Dolphin Foundry, Hunslet, near Leeds, in the county of York, in respect of the invention of "a combined horizontal drilling and planing machine for circular work."
1878 Patent application by Thomas Campbell, John William Campbell, and John Hunter, all of the Dolphin Foundry, Saynor-road, Hunslet, Leeds, in the county of York, in respect of the invention of "improvements in machinery for forging and shaping metals."
1889 Company incorporated
1897 Various boiler-making machines featured in 'The Engineer', 20th August 1897 (for plate bending, boiler end finishing, and a combined circular planing/slotting/drilling machine)
1911 Heavy duty drilling machine for boiler shells
1911 Machines for drilling marine boilers. 
1917 Advert for gear cutting and hobbing
1922 Drilling and Boring machinery
1927 Advert for gears of all types
1938 Acquired by R. W. Crabtree and Sons.