Siam first used a coin machine to produce flat standard coins in the reign of King Mongkut or King Rama IV when Queen Victoria presented a small operating minting machine as a state gift to King Rama IV. This machine was made by the firm that is new Taylor and Challen Ltd. However, the machine was a manual one and consequently had a limited capacity to produce adequate coins to meet the market need. King Rama IV then ordered a complete minting plant from Taylor & Challen at 3,000 Pound Sterling. This plant was used to produced Thai coinage for several decades.
In the early reign of King Chulalongkorn or King Rama V, the machine deteriorated and was in such bad condition that is could not produce sufficient coins to meet demand in the market. At the same time, the forgery of copper and tin coins were widespread. King Rama V then ordered copper coinage from abroad for the first time in 1875. The coin bears on the obverse, the monogram under the coronet with the inscription "Krung Siam” on the left and "the Fifth Reign” on the right. On the reverse, it shows the denomination and year. It was struck in 3 denominations; Sieo, Att and Solos. In 1877, additional ordered were placed for the copper of Siek, Sieo and Att and in 1833 for Siek, Sieo, Att and Solos. It is assumed that these early sets were minted in England probably by James Watt & Co. However it was not until 1890 that an order was made to Birmingham Mint.
Birmingham Mint is the oldest private mint still in operation nowadays. Its history traces back to the year 1850 when Mr. Ralph Heaton II, a diesinker and brassfounder bought at auction the minting equipment of Matthew Boulton’s defunct Soho Mint. It was first operated as Messrs. Ralph Heaton & Sons and since then has struck coins for most of the countries of the British Empire and for other nations in all continents. It became the Birmingham Mint on 22 March 1881. Coinage issues of the Birmingham Mint have different mint marks. However, the most frequently used type style has been the Roman "H” for Heaton.
A Late 19th Century view of The Birmingham mint
The first Thai coin series produced at Birmingham Mint was copper coin of Sieo, Att and Solos which were struck in 1890. The coin bears the effigy of King Chulalongkorn on the obverse and "Phra Siam Devathiraj” or the Diety of the City on the reverse with the year of Rattanakosin - Soc inscribed at the bottom. This was the first issue which was dated in the Rattanakosin – Soc era. This series was also struck in the later year from the mint. Concomitantly, some were also minted in Siam.
In 1898, Siam first adopted the decimal system. As a consequence, the order for nickel 20, 10, 5, and 2 ½ Satang was placed on Birmingham Mint dated 16 February 1898 for the entire issue. The series bore on the obverse, three headed elephant with the inscription in Thai for "Siam Kingdom” above and RS 116 below. The reverse shows a denomination in Thai Numeral in the centre with denomination in Thai letters above and Laurel leaves with the mint mark "H” below. The series, however, was not popular and was then withdrawn from circulation in 1909.
In 1900, the Thai government purchased from Birmingham Mint a minting machine which had the capacity of producing 100,000 coins a day together with a dies for silver of Feung, Saleung and Baht. The coins struck from these dies shows the effigy of King Rama V on the obverse and State Coat of Arms on the reverse. This series was also struck at Birmingham Mint and Hamburg Mint. Those early issues being minted in Siam had no year of issue inscribed on the coins. Later in 1903, a new die was ordered from Birmingham Mint. This time with the year of issue.
Heaton presses newly installed at the Royal Mint, Bangkok, 1903
When the government adapted the decimal system again in 1908, a satang coin of copper 1 Satang, Nickel 5 and 10 Satang were ordered from the Birmingham Mint for many consecutive years with some were minted from Belgium. These coins have a hole in the middle. On the obverse shows the inscriptions "Siam State” and denomination. On reverse is the Chakra with RS year in the inner ring.
In the reign of King Rama VI, the 10, 5, and 1 Satang coins of the same design were struck at the Birmingham mint from 1951 to 1922. The 1922 issue was the last set of Thai coins being struck at the Birmingham Mint. However, the Birmingham Mint and the Royal Thai Mint has continued their good relationship up to the present with many series of blank coins being ordered from the Mint.
James O.Sweeny, A Numismatic History of the BIRMINGHAM mint,Birmingham, England, 1981
Treasury Department, Coinage of Rattanakosin, United Producing, 1982