Ajax Machine Tool was formed by George Carter and Donald Walker in Halifax in 1939. The company was named after the battle cruiser HMS Ajax which had been adopted by the town of Halifax. As the demand for machine tools began to fall off during the 1950s the demand for domestic equipment was increasing. The company developed a new type of washing machine sold under the brand name of ADA washing machines (Ajax Domestic Appliance)

Part of the factory which had been producing machine tools was given over to manufacturing washing machines. The success of the company resulted in it being acquired by Philips International in 1958. The company continued to flourish, Philips purchasing of the company allowed it to use the facilities and in turn increase its production of domestic appliances in the UK.

The company opened offices in Audenshaw, Manchester and later moved to larger premises in Bredbury, Stockport. The access to the European market allowed Ajax to further expand its sales of their machine tools. In 1979 the CEI Group was formed which consisted of around twenty former Philips Group Companies forming a specialist engineering sector. A little later it was transferred to Graseby Plc where the company became involved in Computer Numerical Control of machine tools which continued to grow, with its access to international markets.

The company was returned to private ownership with a management buyout from Graseby in 1992 and in November 2002 under its current owner was relocated to Hampshire.