From the 1730s onwards patentees were also obliged to file a specification which described their invention in technical detail.During the1850s the British patent system was subject to major reforms.
Razors made in USA often left the factory with serial numbers or date codes, which can be used to establish their manufacturing dates. May launch of New Improved razor with new serial number format, starting with 1A.
During certain periods some or all models were unmarked. The Old Type continues as "Brownie" and various other sets, but without serial numbers. In 1930 Gillette stopped using serial numbers on razors.
So razors made from 1930-49 can be difficult to date precisely.
In this year only De Luxe models were numbered, starting with 1-D, and often the final D was omitted.
English patents granted before October 1852 were first printed and published in a numbered sequence in the mid-1850s.
The numbered sequence runs from GB1 of 1617 to GB14359 of September 1852.
Before October 1852, details of granted English patents were simply recorded (enrolled) in the Patent Rolls at the end of a long, cumbersome and costly application process. The details recorded in the Rolls usually included the name, rank and address of the patentee, the title of the invention, a formal recitation of the terms of the monopoly (patent) granted and the date of grant.
However, blades made in those years were stamped with a date code: A for 1930, B for 1931, etc., plus 1-4 for the year quarter. In 1950 this system was expanded to include razors, too (see below).
If a vintage razor is found with its original blades, the blade codes can be used to establish a rough date for the razor.