How are coins made?

1. Ravi wonders how the owl got onto his coin. Coins begin as a long strip of metal, rolled out until it is exactly as thick as a coin.
2. A press punches round discs out of the strip, just as a cookie cutter cuts dough. The discs are called blanks. The strip that is left, full of holes, is melted and used again.
3. Rolling and punching have made the blanks hard. So they are heated in a furnace, which makes the metal soft enough to take a picture. Then they are washed and dried until they shine.
4. The stamps are called dies. A die has the picture cut into it as a hollow, and backwards, like mirror writing. When it is pressed into a blank, the picture comes out raised and the right way round.
5. A blank drops into a ring called a collar, between the two dies. The press squeezes with a huge force. The metal flows into both dies at the same time, and the collar shapes the edge.
6. New coins pour out of the press, many every second. They are checked, and any coin that is faint, bent or the wrong size is taken out and melted down. The good ones are counted into bags.

Tap each part of the press. Watch what moves!

• Ram. The ram is the strong moving part of the press. It drives the top die down onto the blank with a force like many cars stacked on one coin.
• Top die. The top die has one side of the coin's design cut into its face, backwards. It comes down with the ram and presses that picture into the top of the blank.
• Collar. The collar is a strong ring around the blank. It stops the metal squeezing out sideways, so every coin is the same size. Ridges inside the ring press ridges onto the edge of the coin.
• Blank. The blank is a plain, smooth disc of soft metal. In a moment it will be squeezed, and it will have a picture on both sides.
• Bottom die. The bottom die stays still under the blank. It has the other side of the design, so both pictures are pressed at the very same moment.
• Feeder. The feeder takes a blank from the bottom of the stack and slides it into the collar. On its way it pushes the finished coin out. It does this many times every second.

Pull the lever to strike a coin. Compare the picture on the die with the picture on the coin. Then try a lighter squeeze.

Experiment: On the die, the moon is on the right of the owl. Where will the moon be on the coin?

1. Look at the die. Find the moon and the number.
2. Pull the lever to strike a coin.
3. Compare the coin with the die. Tap the coin to flip it and check the other side.

What we found: The coin is a mirror image of the die. Left and right swap over, and the hollows in the die become the raised parts of the coin. That is why the number on a die looks backwards.

Turn on JavaScript to try it yourself.

Mint 3 coins that match the order: the right way round, with a sharp picture, and without wearing out the die. Pick a die, set up the press and strike.

Every coin starts as a strip of metal, rolled until it is just the right thickness. A press punches round discs out of the strip, as a cookie cutter cuts dough. These plain discs are called blanks. The strip that is left over is melted and rolled again.

Punching and rolling make the metal hard, so the blanks are heated in a furnace. Heat makes them softer, which is important for the next step. They are washed until they shine, and their edges are squeezed to make a raised rim.

Now comes the strike. The blank drops into a ring called a collar, between two steel stamps called dies. Each die has one side of the coin's design cut into it as a hollow, backwards. The press squeezes with a force like many cars stacked on one small coin. The metal flows into the hollows of both dies at once, and out comes a coin with a raised picture on each side.

Because the coin is a mirror image of its dies, the artists who design coins have to think backwards. Our play dough comparison works well, with one big difference: metal is far stiffer than dough, so the press must be enormously strong and the dies must be made of very hard steel.

Key words

Blank

A plain metal disc that has not been struck yet. It is also called a planchet.

Die

A hard steel stamp with a picture cut into it, backwards.

Collar

The ring that holds the blank during the strike and shapes the coin's edge.

Annealing

Heating metal to make it softer.

Strike

The squeeze of the press that turns a blank into a coin.

Mint

A factory where coins are made.

Check your thinking

1. How do the pictures get onto a coin?

   Show the answer

   Two dies squeeze the blank so hard that the metal flows into them. The press squeezes so hard that the solid metal flows into the hollow designs.

2. A die has the number 5 cut into it. How does the 5 look on the die?

   Show the answer

   Backwards, like in a mirror. The coin is a mirror image of the die, so the die must be backwards for the coin to read correctly.

3. Why are the blanks heated before they are struck?

   Show the answer

   Heat makes the metal softer, so it takes the picture well. Soft metal flows into the dies with a smaller squeeze, and the dies last longer.

4. What does the collar do?

   Show the answer

   It holds the blank and shapes the edge of the coin. The collar is a ring around the blank. It keeps every coin the same size and makes the edge.