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Engineers, of Stafford. London offices: St Bride's House, Salisbury Square, Fleet Street, London EC
1870 William Henry Dorman started in business.
1882 Subsequently it was converted into a limited liability company W. H. Dorman and Co
1897 The company was incorporated to develop and extend the business
For some years the firm specialised in the production of boot and shoe-making machinery and parts, first for the English and American Shoe Machinery Co.
1910 A special printing press was being made by the firm.
1911 William Henry Dorman retired from the business.
1912 Began making internal combustion engines
1913 "Engineers to the (Motor) Trade; contractors to the Admiralty and War Office".
1914 Claimed to be "internal combustion engine specialists"
1913-1917 For a list of the models and prices of Marine Motors see the 1917 Red Book
1914 Offered to cooperate with British firms to make and market any machine or machine tool of German origin
1919 Walter Haddon was chairman and managing director
1920 At the Darlington Royal Agricultural Show they exhibited petrol driven lighting sets ranging from 5 - 20 kW.
1921 Flexstel expansible and flexible piping in steel
1922 Delivered rock-drilling equipment using the wave-transmission of power to the Bombay Municipality (consisting of three generators and rock drills and piping)
1925 Took over production rights to small single cylinder oil-cooled engines designed by Granville Bradshaw and previously made by James Walmsley and Co (Preston). The engines continued to bear the name 'The Bradshaw' 
1926 29th January - Founder, Mr William Henry Dorman died at the age of 93.
1932 Introduced the Ricardo-Dorman Diesel engine in a six-cylinder and four types of four-cylinder versions.
1934 Orders for petrol engines continued to decline but those for diesels had increased
1939 After a series of court cases when it looked like the company might go into bankruptcy, the company was turned round and paid its first dividend since 1919
1944 Producing the DW and DL engines for marine use.
1987 The Dorman Diesels business was bought by Broadcrown
1993 Perkins of Peterborough acquired Dorman Diesels.
Dorman Diesels Ltd, part of the Diesel and Marine Group, now provide spares and service. See Dorman Diesels website.
1914 Caledon a distributor for Commer found problems with supply and decided to set up its own production using Dorman engines
1920s Lacre Motor Car Co made three-wheel roadsweepers using a Dorman engine
1913 Pagefield produced the N model, a subsidy 4ton lorry using a 42hp Dorman engine and supplied 519 to the Forces. It remained in production until 1931
1919 Ruston and Hornsby attempted to diversify and one outcome was the Ruston-Hornsby car. Two versions were made, a 15.9 hp with a Dorman 2,614 cc engine and a larger 20hp model with 3,308 cc engine of their own manufacture. The cars were expensive and never reached the hoped for production volumes. About 1,500 were made between 1919 and 1924.