This Sunday, February 14, is the 50th anniversary of decimal currency's introduction in Australia.

Former Goulburn coin dealer Richard Cudaj explained to the Post the complete range of currency in Australia prior to 1966.

"We had one, 10, five and 20-pound notes," he said. "In coins, we had threepence, sixpence, shillings and two-shillings, pennies and ha'pennys.

"There were 12 pennies to one shilling and 20 shillings to one pound. A shilling was worth 10 cents.

"Decimal currency made it easier because we were now working in multiples of 10."

Uh-huh. Much easier.

Mr Cudaj continued: "We only ever had a 1937 and 1938 crown, which was worth five shillings (50 cents). There was an ounce of silver in them.

"Until 1945, all coins were made from sterling silver; from 1946, they were made from 50 per cent silver. Sterling silver is 99 percent pure silver. We no longer use silver, we use nickel, copper and tin, so we got cheaper in making coins as we went along. Before 1934, we also had gold sovereigns and half sovereigns."

Mr Cudaj has a rare 1930 penny in his collection, which is safely secured in a bank.

A 1930 penny is worth more than $250,000 today and is a rare find because only 1200 were minted at the height of that decade's Depression: few coins were.

John Saxton is also a Goulburn local and another interesting connection to the 1966 currency changeover.

He was part of the team that worked in secrecy to design the notes and coins that replaced the old currency.

Mr Saxton now lives on a farm near Goulburn and, aged 83, still remembers those days clearly.

"It was all secret squirrel stuff," he said. "I had been a creative designer working in Sydney at the time and I was quite busy. I had a lot of clients.

"In 1963, I received an invitation in the post requesting my presence at a meeting of the newly formed Decimal Currency Board, set up by the Commonwealth Government.

"On arrival at that meeting of the full board, I was informed I was one of six professional artist-designers who had been shortlisted with a view that all six would be commissioned to design the proposed new coinage, the deadline for which had already been set at February 14, 1966.

"We had been chosen by three well-known professionals - graphic designer Douglas Annand; head of the NSW Art Gallery Hal Missingham; and graphic designer/writer Alister Morrison - who had been appointed by the Federal government to act as the decimal currency design advisory panel."

Mr Saxton said he and his five colleagues were sworn to secrecy about the designs as a security measure against counterfeiting of the new notes before their release.

"I still feel like I can't go into the details of the entire operation due to the secrecy of it all, which we all took very seriously," Mr Saxton said.

"Suffice to say that we were surrounded by men with guns when we were designing the new coins. It was a very strange deal indeed.

"I was one of six designers - there are only two of us left now, me and Stuart Debnam - and rather than being responsible for the five cent or the 20 cent individually, we all contributed to the design of all the new currency.

"The amount of work involved in changing the currency was enormous. We had to hand-carve these designs into plaster casts of the coins, and the size of the five and 20 cent pieces we were working on were about as big as [dinner] plates."

Fifty years on, Mr Saxton was philosophical about it all.

"These stories keep popping up, don't they, every 10 years or so. As a society we seem obsessed with milestones," he said.

"Today we have Bitcoin to buy things over the internet and mints use lasers to make coins. It is extraordinary, really, when you stop and think about it."

See the official 1966 animation introducing decimal currency here.