Thwaites and Reed
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.
Sources of Information
- The Times, Mar 22, 1977
-  Company website