Chromium plating

Background:
Although chromium was used in electroplating as far back as the mid 1800s, it took a breakthrough in 1924 by Fink and Eldridge of Columbia University (based on a George Sargent paper of 1920) to make it viable for widespread commercial application. Even then, it probably took the best part of a further decade for the new technique to become widely available and cheap enough to compete with alternatives such as nickel. This slow introduction is borne out by Birmingham Trade directories, which show no chromium plating companies in 1927, then one each in 1928/9, five in 1930 and twelve in 1931. As far as buttons are concerned, a Firmin catalogue from as late as 1933 only offers this finish at a 25% premium over gilt, silver plate and brass, and then only for livery buttons. [Many thanks to Rex Butler for this information].

Badges:

I am currently aware of only six badges that are definitely from the tramway era (i.e., they include 'tramway' in the title) and which are unequivocally chromium plated. I’ve listed these together with the closure dates of the respective systems:
  • Brighton Corporations Tramways cap badge - 1939 - see link
  • Halifax Corporation Tramways - 1939 - see link
  • Manchester Corporation Tramways - 1949 - see link
  • Nottingham Corporation Tramways - 1936 - see link
  • Oldham Corporation Tramways - 1946 - see link
  • Wallasey Corporation Tramways - 1933 - see link (lugs chromium plated as well)
These dates tentatively suggest that chrome badges were first introduced in the early 1930s.

Buttons:
I have examples of several buttons that have almost certainly been finished/manufactured in nickel or brass and have at some point subsequent to this been subjected to ‘chroming’, very probably by a collector. The tell-tale signs are heavy chroming of the front, back and shank, and/or a very heavy shiny finish that obscures the design or even covers what was evidently an already worn front. The following can therefore safely be discounted as genuine:
  • Accrington Corporation Tramways
  • Blackburn Corporation Tramways
  • Lincoln Corporation Tramways
  • Nottingham Corporation Tramways
  • Salford Corporation Tramways
  • Sheffield Corporation Tramways

Buttons which appear genuine, ie, have a chrome front, but a brass back and shank, are listed below, together with the respective closure dates for the systems:
  • Blackpool Corporation Tramways - still open
  • Bolton Corporation Tramways - 1947
  • County Borough of Newport Tramways - 1937
  • Coventry Corporation Tramways - 1940
  • Edinburgh Corporation tramways - 1956 (2-piece blazer style button with chrome shank)
  • Exeter Corporation Tramways - 1931
  • Great Yarmouth Corporation Tramways - 1933
  • Grimsby Corporation Tramways - 1937
  • Huddersfield Corporation Tramways - 1940
  • Leicester City Tramways - 1949
  • Lowestoft Corporation Tramways - 1931
  • Norwich Electric Tramways - 1935
  • Portsmouth Corporation Tramways - 1936
  • Rotherham Corporation Tramways - 1949
  • Stockport Corporation Electric Tramways - 1951
  • Warrington Corporation Tramways - 1935
  • Wigan Corporation Tramways - 1931
  • Yorkshire (West Riding) Electric Tramways - 1932

Perhaps the most interesting of these are Wigan, due to its early closure date, and Stockport. Although the latter closed as late as 1951, the corporation actually changed it’s armorial device in 1932, and all known chrome buttons bear the old device, strongly suggesting that they were manufactured before 1932. Wigan also changed its armorial device, but in 1922, which is clearly too early for chroming, yet all known buttons bearing the newer device are chrome. One explanation for this may be that the corporation waited until it had issued/exhausted stocks of the older buttons before ordering replacements with the newer design, but in chrome.

Taken together, the above suggests that chrome-plated buttons first made their appearance in the very late 1920s and early 1930s, only becoming more widespread as that decade wore on. This still leaves certain puzzles, for example, why on earth operators like the Yorkshire (West Riding) Electric Tramways and Exeter Corporation Tramways would have gone to the extra expense of chrome when closure was probably imminent.