OMT is believed to have been founded in 1939 or 1940 either by, or with the assistance of, Newall Engineering Ltd. to produce metrology (precision measuring) equipment to support their work manufacturing machine tools. The first move was to take over an existing (if small) optical company based at 414 Montrose Avenue in Slough, to the west of London - the site is now a small modern trading estate and OMT's original location occupied by a BMW Service Centre. The timing of OMT's birth was either fortunate or deliberate, for, with the start of WW2 in September 1939, supplies of high-class optical equipment from SIP in Switzerland and Zeiss in Germany would have stopped while demand was expanding exponentially. Consequently, a new factory, to meet the need for these vital items, was, opened in Maidenhead.
It was no accident that OMT's toolmakers' bench microscope appeared to be identical to that manufactured by Carl Zeiss in Germany for, why reinvent the wheel when you have, standing on the bench before you, an example of a world-class item ready to be cloned? The OMT version did have a few differences - the feed-screw micrometer dials were considerably larger (at least on those shown in later catalogues) and minor modifications were made to the major castings and some small fittings. However, as might be expected, the method of operation and accessory ranges were both identical - the OMT sales catalogue is reproduced below and the Zeiss here, as a PDF.
With the war concluded, the Company's first public display was at the British Industries Fair at the Olympia Exhibition Hall in 1947 - by 1962 the company had become part of the Newall group, an organisation specialising in jig borers, grinders, lapping machines measuring and setting gauges, large micrometers and other measuring tools. As an engineering and machine-tool company, Newall existed from 1900 to 1980, though Newall Electronics and Re-Newall continued to operate in Peterborough. Besides OMT, Newall also ran Keighley Grinders and Newall Precision Foundries of Bury (the later starting as James C. Kay & Co. Ltd.) and Machine Tool Electrics Ltd. (Leigh-on-Sea).
1968 saw a new OMT factory established at Helston, in Cornwall, this move being funded by one of the all-too-frequently misguided attempts to spread industry into remote areas - ask the car companies Alfa Romero (Alfasuds) and Rootes Group (Hillman Imp) about how such plans backfire, every time. Despite OMT's activities being recognised, in April 1968, by both the Queen's Award to Industry for Export Achievement and for Technological Innovation, by 1973 it was all over, the factory closed and the 140 staff made redundant. However, the story had not really finished for today the Company (after complex reorganisations and various acquisitions) - is now called Rotary Precision Instruments UK Ltd. and resident in Bath. It continues to manufacture a range of specialised calibration and "precision angular positioning" equipment that includes turbine rotor measurement tools, coordinate measurement and other machines to determine roundness, runout, flatness, parallelism, eccentricity and concentricity.
Early OMT products included a range of high-precision optical measuring and inspection instruments, tank telescope gun sights for the army, ordinary and inclinable circular tables with and without optical scales, a 30-inch automatic indexing rotary table, standard and major horizontal omtimeters, vertical omtimeter, bench-mounted microscopes for use in the toolroom, lathe-tool setting and thread-form inspecting microscopes, optical flats, large and small form of projectors to magnify and check manufactured parts, camera lenses, prisms and a range of precision boring heads. Items added in later years included a 35 mm motion picture projector, some 200 film cameras costing up to £8000 each for the rank organisation, a roundness measuring machine (in competition with the well-known and still-manufactured Taylor Hobson Talyrond), a bench measuring machine accurate to 0.0001" per foot (of an identical function to those also made by the American company of Pratt & Whitney and the Swiss Société Genevoise d'Instruemts de Physique), a projection pantometer for the inspection of parts with three-dimensional contours, specialised, universal and very large projectors (some of the latter weighing over 4 tons), equipment to inspect thread forms, surface-coated mirrors, anti-reflecting coatings, multi-layer films, neutral filters, metallic electrical conducting coatings, 35 mm film printers, cinéradiography cameras, Newall-branded 35 mm cameras for Technicolor Ltd. and even polyhedral prisms designed for experimental colour television in the United States. There was also a department devoted to producing items to meet customers' special requirements.
A fuller account of the OMT story can be found in the splendid website devoted to the Newall group at: http://www.newall.org.uk/omt