. The cap has 22 threads per inch which is English Whitworth fine thread. The Brown cars were built by Brown Brothers Ltd in London between the years of 1901 and 1911. After 1909 they were marketed as the Albruna. Brown Brothers also built the Valveless between 1908 and 1915 and the Dodson between 1910 and 1913. The book “British Car Factories From 1896” shows that David Brown Gear Industries Ltd. Was “formed in 1860 as a manufacturer of wooden patterns for gears and soon developed into a gear manufacturer.” It goes on to say that “car production ended in 1915 as the company concentrated its efforts on the production of heavy gears for the Royal Navy”. This could explain why the gear motif was on the face of the hub cap as the company was always involved with gears.
