Production of UK transport tokens

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Materials used

Early transport tokens were issued in a variety of metals - white metal, copper, brass and cupronickel. Later metallic tokens are mostly aluminium or brass. Non-metallic tokens are often cellulose nitrate (up to around 1940), cellulose acetate (around 1920 to 1960) and polystyrene (around 1960 to date).

The earliest plastic transport tokens are made of cellulose nitrate, often called celluloid. An early dateable issue is that by the Glasgow Tramway and Omnibus Company in 1889. Following the taking over of private tramway companies by Town Corporations, the Corporations started to issue plastic tokens with earliest indicated as being shortly before 1900.

Celluloid sheet was skived off a block (like making wooden veneer) and you can sometimes find parallel fine lines across the token surface - that's a giveaway and indicates pre 1940 and probably 1920s. Blank discs were cut out of the sheet and then stamped in matching dies. The very early tokens are cruder in design than those of later issues.

Towards the end of the First World War it became difficult to obtain celluloid for token manufacture, so 'vulcanised fibre' was resorted to. This was produced by compressing cellulose fibre with zinc chloride to make a sheet material from which the tokens could be made. These tokens loosely resemble hardboard with the faces looking fibrous and the edge tending to showing evidence of splitting. Token design are known to have been issued in both celluloid and vulcanised fibre.

Cellulose nitrate is incredibly inflammable and dangerous to use. When cellulose acetate sheet became available in the 20s it gradually replaced the cellulose nitrate but was still referred to as 'celluloid'. Cellulose nitrate and cellulose acetate look very similar. The main difference is that cellulose nitrate gives off a camphor smell when heated and cellulose acetate gives off a vinegar smell when heated. Few tokens were made from the original Bakelite material, phenol formaldehyde, because of colour restrictions but the colourable urea formaldehyde was extensively used in the 1930s-50s

Some softer tokens were injection moulded in cellulose acetate from the 30's to the 50's but most modern tokens are made from polystyrene. The trouble is that between the two world wars other plastic sheet materials were used with various stamping technologies.

An FTIR spectrophotometer with a good database is useful but not infallible.

Production methods

Production methods leave traces, which are something of an additional guide to dating of the tokens. Metallic tokens and early plastic tokens were struck like coins.

Token die.jpg

The die is a Leeds Corporation Transport canteen token die made by Ardill of Leeds in 1943.

From around 1930, plastic tokens were injection moulded, which leaves a tell-tale edge mark where the molten material was injected into the closed mould - the sprue mark. At first, the moulds would make one token at a time. Such a mould is shown below (©Figleaf).

Mould-top.jpg
Mould-side.jpg

There would have been a number of 'other halves' showing the value on what would be the reverse. The reverse part would have a similar 'gate' which, when the two halves were held together, would provide the means of injecting the syrupy molten plastic into the mould. The plastic would have been injected at about 200 degrees C and would set and shrink as it cooled. There is no provision for removing the heat from the steel mould which would consequently get hotter and hotter which would mean a longer cycle time and very slow production. No cooling channels have been drilled through the mould to allow cold water to keep the mould from getting too hot. So we have a mould giving production rates which were very slow and typical of the 1930s being used to make the new injection moulded tokens.


By the 1950s, multi-impression, cooled moulds offered much lower unit costs and were soon normal.


Incuse tokens.jpg

As with metal coins and tokens, the dies and moulds for plastic tokens wear out and need replaced. There can also be increased production with multiple moulds. Often a master die is made that is in relief (i.e. pattern raised out the same as the final coin/token). This is hardened and used to strike the working dies/moulds. There are some surviving incuse strike tramway tokens that indicate that they were trial strikes using the master die. The examples here show two incuse strikes of Glasgow tramway tokens, a 1/2d and a two stage, with their respective issued tokens. The two stage one is quite distorted, not flat, indicating that master dies may also have been used to tune the production process.

Producers

Known [1] major producers of UK transport tokens include

  • The Birmingham Mint ltd. The company produced all aluminium National Transport Tokens and their forerunner, North West Public Transport until 1992. They received part of the 1994 order for 10 pence tokens The company went into receivership in 2003.
  • Crystalate ltd. Tonbridge. This company has produced celluloid tokens from 1915. At first, brass dies of the various corporation tramway departments were used. In later years Crystalate had their own die sinkers cut dies from steel. Until 1938, the company used hand-operated presses of standard design and pre-punched flans of cellulose acetate sheet. In 1938, Crystalate experimented with an early type of hand-operated injection moulding machine. It still used cellulose acetate, but in a powdered form suitable for pre-heating and injecting into the cold dies. This method was used for over thirty years.
  • Koninklijke Nederlandse Munt, Utrecht, The Netherlands was a state-owned company. It made the National Transport Token £1 pieces dated 2005 and some of the 2003 dated issues, the only UK transport token with a mint mark.
  • Reliance nameplates ltd. Twickenham. In the 1920s this company was the third largest producer of celluloid acetate tokens. These were manufactured from pre-punched blanks of cellulose acetate strip on standard hand-fed presses. In 1948 a fire destroyed the factory and the company had to find new premises. Some unusual tokens were produced prior to the fire but the production method is unknown as all reference to them was lost in the blaze. The unusual tokens had a cardboard centre piece on to which the obverse and reverse sides were held in position by a steel or celluloid ring. The company continued to use the original type of press until 1963 when the production of celluloid acetate tokens was discontinued.
  • H. B. Sale ltd., Birmingham. This company has manufactured metal tokens from the beginning of the century. Injection moulded celluloid tokens were first made in the 1950s.
  • A. Wheatley ltd., Stockport. This company produced tokens on a large injection moulding machine. The die plates hold up to sixteen sets of tokens at a time. The ejector pins which push the tokens out after impression leave marks on the reverse of the tokens.
  • Roger Williams Mint, Attleborugh, Massachusetts, USA. The company shared an order from National Transport Token for 10 pence aluminium tokens dated 1994 with The Birmingham Mint ltd. and won a follow-up order for the 1995 dated 10 pence tokens.
  • F. E. Wilson ltd. Sutton Coldfield. This company uses a semi-automatic machine which is basically of the same design as the standard hand-fed presses. The .070 in. thick cellulose acetate sheet for the pre-punched blanks was supplied by Xylonite Ltd. Tokens, in a standard range of colours. Later, cellulose nitrate acetate supplied by Bakelite Xylonite ltd, was used.
  • Woolen & Co. ltd. Sheffield. This company was a major producer of transport tokens from the 1920s. Their premises were bombed during the second world war and all old records, early dies and samples were lost. The original presses were hand-operated. They used pre-punched blanks of either cellulose acetate or vulcanized fibre. The blanks were heated before being hand-fed into the press. Woolen also made non-round tokens, such as those for Hull and Nottingham. In the late 1950s, it produced twelve-sided tokens for Sheffield and Northern General. In 1961, Woolen bought an automatic injection moulding press and produced dies for it.
  1. Aspects of Transport Tokens, by Priscilla Langridge in Coin Monthly, September 1972