Grace's Guide is the leading source of historical information on industry and manufacturing in Britain. This web publication contains 148,159 pages of information and 233,681 images on early companies, their products and the people who designed and built them.
of Clerkenwell, London.
Scientific instrument and Clockmakers.
1740 Founded by Aynsworth Thwaites who made the Horse Guards Parade clock which was still working 200+ years later
1856 Mr Buggins joined the firm and his descendants continued to be associated with the business for >100 years
The firm continues in business 
The book 'London's Industrial Heritage' by Aubrey Wilson (David & Charles, 1967) features a description and illustration of a gear cutting machine in use in the 1960s, having been made by the company over 100 years earlier.