The Royal Australian Mint in Canberra can make 650 new Australian coins every minute and up to two million coins a day. Imagine having all those in your pocket or your bank account!
But making the very first of any new Australian coin is a long and delicate* process that can take months, or perhaps even years.
Here’s how it happens.
IDEAS AND DESIGNS
When a new coin is needed, a team of coin developers, designers and engineers* work together on how they would like the new coin to look.
Next time you get a coin, look at it and also close your eyes and feel it carefully, considering how many decisions need to be made. These decisions could include: what it is made out of and its size and shape, whether the Queen’s effigy* will stay the same on the heads side as for previous coins, what design will go on the tails side and what pattern will be around the edge.
Some features are to make different coins obviously different for vision-impaired people and for when machines sort them. The 10 cent coin, for instance, is a similar size to the $1, but the 10 cent has grooves all around the edges and the $1 has grooves and smooth areas alternating.
Once everyone has decided on how it will look, coin designers make and sculpt a large plaster model of the coin. Sometimes, instead of plaster, the designers use computers and 3D modelling software.
MAKING THE COIN-MAKING TOOLS
From the finished model a steel model is made called a master tool. A computer-controlled engraving* machine makes this steel model and this can take 24 hours.
The finished steel model is put into a strong press and, in a process called hobbing*, the design is pressed (using 100-400 tonnes of pressure!) into a softened steel block. The result is a negative coin, like a mould. Where there are raised features or bits that stick out on a real coin, on the negative this feature would be hollowed out. This process of making a model and then a negative is repeated a couple of times until a final negative is made of the right kind of steel. Finally, a working hob, which is a negative, like a mould, is made. This is called a production die*.
Machines cut coin-shaped pieces from sheets. The metals are a mixture of copper, nickel and aluminium. 5c, 10c, 20c and 50c coins are 75 per cent copper and 25 per cent nickel. The $1 and $2 coins are made from 92 per cent copper, six per cent aluminium and two per cent nickel.
These coin-shaped pieces are called blanks, because they don’t have a design on them. They are round, except for the 50 cent blanks, which have 12 sides, called a dodecagonal.
The blanks are rolled through a machine with a groove in it, which makes a raised edge. They then go through a press, with the design for both sides being pressed into the coin at once with the production die. They spread and stretch a little when they are pressed, which pushes them into the sides of the die, pushing little grooves into the edge.
Proof coins are made in manual presses that work quite slowly. Proof coins are test coins. Mint press operators look at these coins very carefully with magnifying glasses to check for imperfections*. Any that aren’t perfect are sent away to be melted down.
Once the proofs are perfect, circulating coins can be pressed quickly, then counted, packaged and weighed and stored in vaults* at the Mint until they are sent to banks and then out into circulation.
Each coin stays in circulation for about 30 years.
Source: Royal Australian Mint
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- delicate: fragile or detailed
- engineers: the person who works out how to make something
- effigy: sculpture or model of a person
- engraving: cut or carve a design
- hobbing: pressing and shaping steel to make a tool
- die: used to force a shape onto a hard surface
- imperfections: mistakes that stop it from being perfect
- vaults: safes
LISTEN TO TODAY’S STORY
- How many coins does the Mint make a day?
- What is the difference between the edge of a 10 cent and a $1?
- What material is used to sculpt a large model of the coin?
- What three metals mentioned are used in coins?
- How long do coins stay in circulation for?
The following dot points are the simplified steps of making and distributing a new coin but they are jumbled up. Use the article to help you put them back into the correct order.
- Machine cuts coin-shaped pieces of metal called blanks.
- Sculpt a large plaster model of the coin.
- Identify and fix imperfections in the proof coins.
- Make negative models to create a production die.
- Circulate new coins via banks.
- Decide on the design for the new coin.
- Roll blanks through a machine to create a raised edge.
- Make a steel model called a master tool.
- Machine press, count, package and weigh coins.
- Manually press proof coins.
Extra resources: Printed copies of the dot points to cut and paste into the correct order.
If Australia was to introduce a completely new coin:
- -What amount do you think it should be? Why would a coin of this amount be useful?
- -Draw what you think it should look like. (Think about the designs on existing coins and use this to guide you.)
- -Explain how you have made it easily identifiable for vision-impaired people.
Time: Allow 20 minutes
Curriculum links: English, Critical and Creative Thinking
With a partner see if you can you identify all the doing words/verbs in this text. Highlight them in yellow and then make a list of them all down your page. Now see if you and your partner can come up with a synonym for the chosen verb. Make sure it still makes sense in the context it was taken from.
Try to replace some of the original verbs with your synonyms and discuss if any are better and why.
HAVE YOUR SAY: What would you put on the tails side of a new coin? Use full sentences to explain your thinking. No one-word answers.