Royal Mint Experience a collaborative effort
- Published: Jun 4, 2016, 4 AM
Editor's note: This is the second part of a story by Coin World London Correspondent John Andrew about his visit to the Royal Mint Experience, the Mint's new visitor's center with tour. The original story appears in the June 20 issue of Coin World.
Having the idea was one thing, but converting it into a meaningful and interesting attraction was another.
The business of the Royal Mint of course is making money, not running visitor centers, so the Royal Mint partnered with Mather & Co., a design consultancy, and the Continuum Group, the leading operator of cultural visitor attractions in the United Kingdom.
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The tour of the attraction begins with a short introductory film hosted by Dan Snow, the British television presenter, who regularly presents history programs for the BBC. He also hosts similar introductions at other UK attractions such as the Mary Rose, Henry VIII’s warship that sank in 1545.
This was cleverly done with Snow appearing to be walking around stacks of coins and across their surfaces. The diminutive or shrunken Snow walking across the reverse of a coin is etched on my mind whereas his words, while engaging at the time, have vanished into oblivion.
Our friendly guide then led our small group into the first room where we began to learn about how a coin is made and what they are made from. With the increase in metal prices in recent decades “coppers” are no longer struck from bronze (97 percent copper, 2.5 percent zinc and 0.5 percent tin) but from copper-plated steel. And while most of the “silver” is copper-nickel (75 percent copper, 25 percent nickel), since 2012 the United Kingdom’s 10 and 5-penny coins are made from nickel-plated steel.
We learn that the Royal Mint prepares the alloy in its own furnace, which can reach temperatures of 1,450°C. After sampling the molten metal to confirm that the composition is correct, the melt is then poured into a holding furnace. After it has cooled, the metal is rolled into a continuous strip, usually about 16 millimeters thick.
Casting impurities are removed from the surface of the strip with a scalping machine. This removes around 0.5 millimeter of the surface. The strips, now bright and shiny, are then wound into large coils, weighing up to three-tons. Of course, coins are of varying thicknesses, so the strips have to be further rolled, initially with a heavy roller to get to a 3-millimeter thickness, with a further reduction being achieved with a finishing mill until the thickness is of the required specification.
The strips are then fed into a blanking machine so that a blank of the correct diameter is prepared on which to strike the coin’s design. Around 480,000 blanks for 1-penny pieces can be punched from a single coil of steel at a rate of some 8,000 blanks a minute.
However, that is not quite the end of the story. Up to four more processes are required before the coin can be struck. First the blanks are fed into a rimming machine where they bounce around and, as if by magic, a rim appears around the diameters. This aids the stacking of the coins and protects design elements when the coins enter circulation. If plating is required, then this can be undertaken by the mint.
All this rolling and striking hardens the blanks. So as to get the metal into a better state for striking, the blanks are softened by a process known as annealing. The blanks pass along a conveyor belt through an annealing furnace, which operates at temperatures of up to 950°C.
When the blanks emerge from the furnace they are somewhat blemished. They are then cleaned by being placed in rotating drums containing an acid solution and ball bearings. After a final wash and drying they are ready for being transformed into a coin.
The door then opens into a different world — the Royal Mint’s Coin Press Room.
Seeing coins struck
We were not actually in it, but looking at the activity through a large glass window. The coin presses are big and on the top of each is a large container called a hopper. These are full of now clean and shining blanks. Each blank is fed into perfectly sized recesses in a circular plate. The plate rotates, then the blank is held in place by a collar as it sits between a pair of dies. With one strike the reverse, obverse and edge are struck simultaneously using from 60 to 150 tons of pressure.
The £2 piece is a ringed bimetallic coin comprising two separate blanks. The “silver” center is made of copper-nickel and the “gold” outer ring is made of nickel-brass.
To create the ring, a nickel-brass blank is placed in a collar bearing the lettering for its edge and the center is pierced out and recycled. The copper-nickel blank is prepared with a diameter that will loosely fit into the outer ring. It has groove around its edge. The outer rings and center blanks are placed in separate hoppers above a coining press and are fed together into the recesses of the circular plate. The centers fall into the rings and as the plate rotates, the blanks come into contact with a collar and a pair of dies. With one blow the obverse and reverse are struck and the center fuses to the ring, while the collar imparts the milled edge to the ring. After this last step, the edge now bears both an inscription and reeding.
It was fascinating to watch the coins spewing out of the presses into storage containers. The presses strike around 750 coins a minute. Just prior to our moving on, a small fanlight window was opened into the Coin Press Room. Our quiet haven of a viewing gallery was immediately broken by one almighty clatter. It certainly emphasized that the mint was a factory.
The next room was tranquil but quite dramatic — there were large crates full of £1 coins, some with glass sides to reveal the contents. It was impressive.
This provided a photo opportunity. Whereas a family group may well adopt a theatrical WOW! posture with arms raised yelling “It’s all mine,” our group comprising two journalists and two officials from the Continuum Group stood sedately smiling. However, the excitement was not yet over — we were invited to strike our very own coin!
No, we were not allowed to place the blank in the press or remove the coin after striking — that was undertaken by an official — but we did press the button that resulted in a blank being transformed into a coin.
This was no ordinary £1 coin, but an example of a 2016 round pound that will not be placed into circulation (please see related story, page 5). In March 2017, the United Kingdom will replace the round pounds with a new 12-sided denomination with many security features. This move has been taken as it is estimated that one-in-four of the £1 coins in circulation are fake.
Striking your own coin costs £3.50 and it is presented to you in a sealed presentation pack titled “I struck this coin.”
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