Great Britain 1988 One Penny Faulty Planchet Error


As originally published in Australasian Coin and Banknote Magazine in September 2022.

What Went Wrong -error coins that escaped the Mint

Figure 1 – Great Britain 1988 One Penny Struck on Faulty Planchet Error

We’re going to discuss an error coin this month that originated from an overseas mint. A mint that, in times of need, has struck Australian coins. If you have an interest in collecting error coins you will realise some error types are rarely seen on Australian coins. Often those error types are more easily found on a coin from another country and still fit nicely into a collection. Even better, often errors on foreign coins are found at just a fraction of the price that a similar Australian coin error may cost.

The error coin featured this month (Figure 1) is a Great Britain one penny dated 1988. At first glance it looks perhaps like someone with a Dremel in the tool shop was attempting to carve it into shape for a jewellery piece. It is severely underweight at 2.75g instead of 3.56g, but you don’t have to be an error expert to guess that would be the case. But is it actually an error or a fabrication? Closer inspection by the knowledgeable collector indicates that it is indeed a real error and not someone’s metal-work project.

There are two features seen on this coin that suggest it is a genuine error. The first is the jagged edge planchet flaws to the left of the N of PENNY on the reverse. This is typical of metal impurity in the planchet that may fall out either before or after the coin is struck.

Figure 2 – Great Britain 1988 One Penny Struck on Faulty Planchet Error Detail

The second feature is one we’ve spoken about before in a different context, but the principle still applies here. Just as metal flows into the void of a clipped planchet, metal can be seen to have flowed into the missing area of this coin. On the obverse, the second I of ELIZABETH II is skinny which is an example of elongated fishtailing. The fault edges, in particular through HM’s neck are also tapered indicating there was no restriction on the metal at the time of the strike. Figure 2 shows close up detail of the crown above the portcullis on the reverse where fishtailing has again occurred with metal flowing into the void.

Thus, we have a genuine error here, a coin struck on a faulty planchet. But why was the planchet faulty? This coin’s planchet was cut from an area of a rolled metal strip that had a rather large inclusion present. This inclusion, in the most part, fell away from the planchet before the coin was struck.

Mark Nemtsas and Kathryn Harris own and run ‘The Purple Penny’ coin shop in Adelaide and are passionate about error coins.

Posted in Error Coins

Australia 1956 Florin Struck Out of Collar Error


As originally published in Australasian Coin and Banknote Magazine in August 2022.

What Went Wrong -error coins that escaped the Mint

Figure 1 – Australia 1956 Florin Struck Out of Collar Error

If you’ve been reading our articles each month you will be familiar with the collar die, the third die used when striking coins. It is an integral part of the coining process as it is one way of imparting edge design such as reeding. For a round coin, the collar die is shaped like a hollow cylinder and constrains the blank as the coin is struck. This ensures all coins struck are relatively uniform in shape and size and that they adhere to specifications.

The coin we see in Figure 1 is not uniform in shape and does not adhere to the exacting specifications of the Australian florin. Also, it does not show any edge reeding whatsoever. Was this coin struck without that essential third (collar) die?

Due to the complete lack of edge reeding, we can most certainly say yes. The coin was clearly not constrained when struck resulting in a coin with a larger diameter than specified. It is also out-of-round and would most certainly be rejected in coin counting and rolling machines. The nickname for this error-type, the “pancake” came about from the noticeably enlarged and distorted planchet.

Figure 2 – Australia 1956 Florin Struck Out of Collar Error Detail

Is there any more evidence of the lack of a collar die? The answer is yes. The legends around the entire obverse and reverse have fish-tailing of the lettering which is an indication of radial metal flow (see Figure 2). The coin metal in the letters has flowed outwards leaving a deficit of metal towards the centre of the coin giving rise to the clear ‘fish-tail’ shape of each letter. Similarly, the stars around FLORIN on the reverse have a strange drawn-out appearance as again, the metal flowed into the parts of the stars closest to the rim. Finally note the smeared look of the reverse rim denticles rather than being the neat tooth-shaped features they should be (see Figure 2).

The force of the strike has also spread the planchet so much that it is larger in diameter than the dies striking it, which meant parts of the planchet were not struck at all. These unstruck areas are seen behind Her Majesty’s head on the obverse and from 10 o’clock to 5 o’clock on the reverse.

This 1956 florin struck completely out of collar is a superb error coin in lovely uncirculated condition. It is particularly appealing to error collectors as it is struck on a relatively large silver coin, certainly making it much harder to find and thus more desirable.

Mark Nemtsas and Kathryn Harris own and run ‘The Purple Penny’ coin shop in Adelaide and are passionate about error coins.

Posted in Error Coins

Australia 1966-1984 Ten Cent Die Adjustment Strike Error


As originally published in Australasian Coin and Banknote Magazine in June 2022.

What Went Wrong -error coins that escaped the Mint

Figure 1 – Australia 1966-1984 Die Adjustment Strike Error

Manufacturing coins is a high-pressure business, both figuratively and literally! What sorts of pressures are involved in making a coin? 35 tonnes and upward, with some sources suggesting proof coins need striking pressures of 500 tonnes and more [1]. Of course, the higher the pressure the more potential for damage and wear to both the coin dies and the coin press. On the other hand, if the pressure is too low the coin will be poorly struck and not meet the exacting standards that countries demand of their circulating coinage.

The coin shown with this article has clearly been struck at the lower end of the pressure range. Observe that the centre of the coin shows the ten cent design as you’d expect, the chin and hair of the Arnold Machin portrait of the Queen, and the feathers of the lyrebird as sculpted by Stuart Devlin. Move out toward the rim though, and the design fades smoothly until nothing is present at all. Note also that the characteristics of the strike are very similar on both sides. Clearly the coin shown is an error but what type of error?

The error coin here is usually called a ‘die adjustment strike’. The theory being that when a coin press and set of dies are first set up the press operator will gradually wind up the striking pressure to achieve a balance between quality of strike and minimising die wear and tear. As the pressure changes these ‘die adjustment strike’ coins are created. Presumably the test strikes would be collected up and scrapped for re-processing but every now and again one might sneak into the production coins and escape into circulation. It’s a nice theory and we’d like to think that this is how this coin came to be.

Of course, you’d see EXACTLY the same effect if there was a temporary fluctuation in striking pressure during a production run. This might be due to some sort of machine failure and could result in dozens of low-pressure strike coins being made and reaching circulation. We’ll never know if the coin shown was created as part of the setup process of a coin press or if it was a genuine error created during a production run of coins. Either way it managed to escape the Royal Australian Mint sometime between 1966 and 1984 and is a fine example of the so-called ‘die adjustment strike’ error.

Mark Nemtsas and Kathryn Harris own and run ‘The Purple Penny’ coin shop in Adelaide and are passionate about error coins.

  1. United States Mint : Coin Production [online] Available at: https://www.usmint.gov/learn/production-process/coin-production [Accessed 10 April 2022].
Posted in Error Coins

Australia 1964 Penny Struck Through Scrap Error

As originally published in Australasian Coin and Banknote Magazine in July 2022.

What Went Wrong -error coins that escaped the Mint

Figure 1 – Australia 1964 Struck Through Scrap on Obverse Error

We’re sure that coin producers do their best to keep the process of making coins a neat and tidy one. However, as with most manufacturing, contamination can and does occur through most of the processes needed to make a coin. When a contaminant gets into the coin press and is struck along with the coin, we get what is known as a ‘strike through error’. That is, the coin has been struck through some sort of foreign material. We’ve seen many strike through errors over the years, the most common are coins struck through oil or grease. Less common are coins struck through scrap metal, and that’s what you can see in Figure 1.

What you’re looking at is a 1964 penny struck in Melbourne. It’s in quite a nice grade as most are, but on the obverse portrait of the Queen you’ll see a peculiar impression that looks for all the world like the number 7 stamped into the coin. If you examine the image closely (Figure 2), you’ll see that the surface of the impression is slightly textured and in the corner there appears to be a fold. It doesn’t take too much imagination to think of a longish strip of thin metal that has been folded somehow getting into the blank penny supply and being fed into the coin press along with a coin blank. The blank is struck with the stray metal strip in the way leaving an impression of the strip. When the coin is ejected the two part company and you’re left with the coin we’re discussing.

Figure 2 – Australia 1964 Struck Through Scrap Detail

Where did the scrap of metal come from? We’ll never know for certain but there is one very strong possibility. The strip was a detached planchet flaw. A planchet flaw is a piece of improperly bonded metal that is attached to a coin blank. It’s improperly bonded because of some sort of impurity in the metal the blanks are made from. Sometimes planchet flaws are very poorly bonded to the coin blank and detach to potentially get in the way of a coin when it is struck. Coincidentally there’s an example of a planchet flaw on this very coin. On the obverse of the coin running from the Queen’s shoulder down to the G of GRATIA is a wedge-shaped dark feature, which is, in fact, a planchet flaw!

What a great error of this type to put into one’s collection. It’s in decent condition with all design elements clear and virtually unworn, the strike through is large and obvious, and the shape of the strike through is interesting. These are all criteria that collectors should take into account when purchasing error coins of this type.

Mark Nemtsas and Kathryn Harris own and run ‘The Purple Penny’ coin shop in Adelaide and are passionate about error coins.

Posted in Error Coins

Australia 2016 “Alien” Die Clash 50th Anniversary of Decimal Currency Five Cent

As originally published in Australasian Coin and Banknote Magazine in May 2022.

What Went Wrong -error coins that escaped the Mint

Figure 1 – Australia 2016 Five Cent “Alien” Die Clash

What we have to show this month is a very unique character, the 2016 ‘Alien’ five cent (see Figure 1), and one could be hiding in your wallet or purse. We’ll just wait whilst you go take a look…….

In the image you see a coin that was part of the 2016 50th Anniversary of Decimal Currency series. These were the first Australian circulating coins to feature a commemorative obverse instead of the reverse. The obverse has a small Ian Rank-Broadley portrait of Queen Elizabeth II above the iconic 1938-1964 penny as designed by George Kruger-Gray. It shows die clash (see Figure 2) as two curved raised shapes extending from the top right and top left of the penny. They resemble nothing more than a pair of very out-of-this-world antenna. The antennae in question have given the face-like round penny design element a very alien appearance and the prices these coins fetch compared to their face value is astronomical!

Figure 2 – Australia 2016 Five Cent “Alien” Die Clash Detail

What is die clash? Die clash happens when the obverse and reverse dies come together without a coin blank in between. They strike each other with such force that sometimes the partial impression of one die is left in incuse form on the other. All subsequent coins struck by the die pair are a new variety as they show the die clash as additional and unintended design features. Usually when clash is present on a coin it is worth noting when describing it fully, but doesn’t necessarily add any significant value to the piece.

Our coin however, has the distinctive raised curved features, that without too much imagination give it an other-worldly appearance and the obvious reason for the ‘Alien’ nickname of this variety. Where exactly did these die-clashed “antennae” come from? They are in fact the impression of the space between the echidna’s face/beak and paws from the clashed reverse die.

We’ve only ever handled three of these special “Alien” die clash coins and very few have been found by coin noodlers. Their nickname and scarcity have given them cult status in the decimal collecting community and perhaps they should be called the “Alien Overlord” variety to truly convey their importance! Be they “Aliens” or “Alien Overlords” there’s no denying collectors want them with the last three recorded sales of the type in the $400 to $600 range. To paraphrase fictional newsreader Kent Brockman, the authors welcome our new alien overlords!

Mark Nemtsas and Kathryn Harris own and run ‘The Purple Penny’ coin shop in Adelaide and are passionate about error coins.

Posted in Error Coins

Australia 1942I/1943I Penny Brockage Error

As originally published in Australasian Coin and Banknote Magazine.

What Went Wrong -error coins that escaped the Mint

Figure 1 – Australia 1942I/1943I Obverse Brockage Error

The image shown along with this article is one that plays tricks with your eyes. Are you looking at two distinct coins with different lighting and subject to some sort of image mirroring? Or is it, perhaps, the same coin that has somehow been struck in error? Of course, the image depicts both sides of the same coin, but it’s confusing enough to warrant more explanation. On the left you’re seeing the obverse of a 1942 or 1943 penny struck in Bombay, India. On the right an incused mirror image obverse of exactly the same thing. How, we hear you ask, is that possible?

In most basic terms the sequence of operations goes something like this:

  1. A coin is struck between the obverse and reverse dies.
  2. For some reason the coin fails to be ejected from the coin press and becomes jammed onto one of the dies. In the case of this example a coin was jammed onto the reverse die. This jammed coin is known as a die cap.
  3. A new coin blank is fed into the coin press and is positioned in the collar die.
  4. The coin blank is struck by the obverse die and the obverse of the stuck die cap. This forms a normal obverse strike on the coin blank and a mirror image obverse strike on what should be the reverse. This coin is known as a brockage.
  5. The brockage is ejected and another blank is fed into the coin press and another brockage is struck. And so on until the die cap is destroyed, dislodged, the coin press jams, or a press operator notices the problem and stops the production run.

Now we know how the coin shown was formed and we know what it is called, as a thought exercise it’s worth considering the die cap that struck our error coin. The brockage strike here is crisp and full which suggests that the brockage was among the first few coins struck by the die cap. It is, in error coin terms, a brockage struck by an early state die cap.

Why is this the case? In comparison to a coin die which is made from specially hardened tool steel, the bronze of a penny is ductile and prone to deformation under repeated impacts. This means that with each coin struck by a die cap it deforms and stretches and the design becomes softer and more stretched, as does each brockage strike it creates. Eventually all the design will be obliterated and no mirror image will be visible on struck coins and you’ll just see a smooth surface. Those error coins are known as brockages struck by a late state die cap.

Brockages of any coin in the Australian coin series are sought after, with early state examples like this one particularly desirable. The penny and half penny pre-decimal series provides the best opportunity of obtaining a nice example at an affordable price. Brockages in the decimal series are rare indeed and one must be willing to compete strongly with other collectors if wanting to obtain one!

Mark Nemtsas and Kathryn Harris own and run ‘The Purple Penny’ coin shop in Adelaide and are passionate about error coins.

Posted in Error Coins

Australia 1966 Five Cent Upset Error

As originally published in Australasian Coin and Banknote Magazine.

What Went Wrong -error coins that escaped the Mint

Figure 1 – 1966 Five Cent Upset Die Error

Back in the May 2021 edition of The Australasian Coin & Banknote Magazine (Volume 24 / Number 4) we talked about London minted 1966 10 cent coins with upset / rotated die errors. What we didn’t mention in that article is that 1966 5 cent coins, also minted in London, have been very occasionally sighted struck with die rotations. When we wrote the article we’d never actually seen a 1966 five cent die rotation, just a picture of one.

We’ve always been keen to get our hands on an upset 5c and for many years we’ve checked each and every coin that we’ve seen without success. Having examined many hundreds of potential candidates we were beginning to think that we were never going to find one. Then in mid-December 2021 a video post appeared on the popular Facebook group “The Gravy Train”. A collector in Victoria showed four upset 1966 five cent coins that had been found in a ‘coin noodling’ session. Each appeared to be in high grade, suggesting that the coins had been recently removed from a collection or money box and deposited in the bank. We were just a bit envious of the collector who discovered the errors as we would have loved to have one for our own collection!

Then when we opened up our retail shop, The Purple Penny, in the first week of 2022 we were surprised to get a visit from the very same Victorian collector! He had brought along his four upset 1966 5 cent coins and was kind enough to sell us one and allow us to examine the other three. Figure 1 shows the coin we purchased. You can see that the obverse is rotated 270o with respect to the reverse and that the coin is in lovely virtually uncirculated condition. This supports the idea that these errors only re-entered circulation very recently. More observations made on the coin shown and the other three viewed are:

1. Each coin had the same die gouge on the obverse indicating they were all struck by the same dies. See Figure 2.
2. As with the 1966 10 cent upset coin errors the coins were struck at the Royal Mint in London. Each 5 cent showed the long spine mintmark in the correct location on the reverse. See Figure 3.
3. All four errors had a slightly different degree of rotation. Careful note was taken of the alignment of the edge milling in relation to the point of the first A of Australia on the obverse. This was found to vary for each coin which indicates the OBVERSE die was rotating as these error coins were struck. See Figure 4.

Figure 2 – Characteristic Die Gouge

Figure 3 – London Mintmark

Figure 4 – Edge Milling

We’re both delighted to have obtained one of these elusive upset die coin errors and it will sit nicely alongside our 10 cent examples. We cannot thank the Victorian collector and his wife enough for taking the time to pop in for a visit and allow us to buy one of these lovely little errors!

Mark Nemtsas and Kathryn Harris own and run ‘The Purple Penny’ coin shop in Adelaide and are passionate about error coins.

Posted in Error Coins

1986 Mint Set Error – 20 Cent Struck Through Oil or Debris

As originally published in Australasian Coin and Banknote Magazine.

What Went Wrong -error coins that escaped the Mint

Figure 1 – 1986 20 cent struck through oil or debris

Figure 1 shows a 20 cent with two areas that have been struck through either oil or debris. The ‘strike through’ error is a catch-all term that covers the family of errors where some sort of foreign material comes between the coin die and the blank planchet when it is struck. This results in an area of the coin design being largely obscured or completely obliterated. What sorts of foreign material can come between the planchet and the die? Most commonly, it’s oil or grease. Less commonly it might be scrap metal or swarf, cloth, wire, cotton, or very rarely a screw or some other metal fastener.

In the case of the coin shown in Figure 1 there are two main struck through areas, one above and through the Queen’s crown and one below the truncation of the portrait. We’re not 100% certain what the foreign material was that caused the error. However, if pressed we’d suggest the strike through at the top of the coin was through grease or oil due to the uneven rounded nature of the flaw. The one at the bottom of the coin looks different, more angular and regular with a linear nature which may indicate it was struck through a bit of scrap metal.

Figure 2 – 1986 Mint Set Error

What really makes this error interesting though, is that it’s housed in a 1986 mint set! See Figure 2. Somehow this error escaped the Royal Australian Mint after going through many more quality checks than a run-of-the-mill circulation coin. Mint set coins are handled differently to circulation coins, hand packaged, and presumably each coin is given an eyeball quality check by packaging staff. Clearly this little gem slipped through all of that and is still housed in the original mint set packaging. Sure, it’s not the best mint set error we’ve ever seen, but it’s certainly one worth putting into a quality collection of errors.

Mark Nemtsas and Kathryn Harris own and run ‘The Purple Penny’ coin shop in Adelaide and are passionate about error coins.

Posted in Error Coins

Australia 1964 Penny Error – Double Struck in Collar

As originally published in Australasian Coin and Banknote Magazine Yearbook for 2021/2022

What Went Wrong -error coins that escaped the Mint

Figure 1 – Australia 1964 Penny Error – Double Struck in Collar

Figure 1 shows an interesting Melbourne minted 1964 penny. The sharp-eyed reader will likely be drawn to the double forehead of Her Majesty on the obverse. On the reverse there is great interest in the second set of numerals 964 just below the date (see Figure 2). What is the cause of both of these distinguishing features?

This 1964 penny is correctly classified as “double struck in collar” or perhaps a “rotated double strike”. Both terms are accurate and both add valuable information that help us understand the error. What you are looking at is a 1964 penny that was struck once in the normal fashion. However, something then went wrong with the coin press and the coin failed to eject properly from the collar die. It did move during the failed ejection, rotating perhaps 10 degrees or so before settling back into the collar. The coin was then struck again and after this second strike the penny ejected correctly and entered circulation. The grade is excellent so clearly some vigilant individual saw it very quickly and it was put aside as an item of curiosity.

Figure 2 – Detail, Second set of numerals 964 below date.

Knowing that this coin has been struck twice within the collar we can now look with fresh eyes at the Queen’s double forehead and that second set of 964 numerals. What are they? They are of course remnants of the first time this coin was struck, somewhat obliterated by the second strike. Understanding this we can examine the rest of the coin and see other features that betray the nature of the error. Look at the lumpy surfaces of AUSTRALIA on the reverse, see the ghostly remnants of a G between DEI and GRATIA on the obverse, and note that the Queen has also gained a second neck line!

The ”double struck in collar” error is a particularly interesting one, especially when the rotation between strikes is large enough to give rise to strong indicators observed on this coin. It’s an error type to look out for, and for the more advanced collector, identify coins that have been struck more than twice in collar! We’ve seen one coin that was struck 6 or 7 times in collar, but that’s a story for another day.

Mark Nemtsas and Kathryn Harris own and run The Purple Penny coin shop in Adelaide coin shop in Adelaide and are passionate about error coins.

Posted in Error Coins

Australia 1966-1984 2 Cent Struck on Split Planchet

As originally published in Australasian Coin and Banknote Magazine November 2021

What Went Wrong -error coins that escaped the Mint

Figure 1 – Australia 1966-1984 2 Cent Struck on Split Planchet

This month we have the pleasure of showcasing an error coin that is very rare indeed. What looks at first glance to be a pretty rubbish two cent piece is one of the hardest error types to find.

This coin is underweight and considerably thinner than it should be. Looking at the heavily striated surface texture of the reverse allows us to identify that it was here that a fatal flaw occurred. It’s along this face that the planchet split in half along a line parallel to the surfaces of the blank. One half of that split planchet went on to be struck into the two cent piece you see here.

The weakness in the strike we see on both sides of the coin resulted from the split planchet being severely underweight. The strike weakness is not uniform as the planchet was thicker and thinner in different areas. However, in general there is weakness on the periphery and in the centre of the coin the features are more strongly struck. The area where the planchet was the thinnest was behind Her Majesty’s head and in front of the frill-necked lizard’s face.

With regard to scarcity this error coin has two characteristics that make it extremely difficult to find. Firstly, it is very unusual to come across a split planchet one or two cent coin. By comparison, it is very common to see split planchet copper nickel coins, especially on the 5c and 10c denominations. Secondly, of all the types of split planchet errors the ‘struck after split’ type is by far the hardest to find. It’s important to understand that there are several types of split planchet errors that can found. These may be partially split and open like a clamshell, a planchet that has fully split and is retained as a mated pair or fully split and only half the coin being present. Each of those types split after the coins were struck. In the case of our coin the coin has split and then been struck easily making it the hardest to find type of split planchet error.

We’d like to thank the owner for allowing us to image and admire this error coin.

Mark Nemtsas and Kathryn Harris own and run The Purple Penny coin shop in Adelaide coin shop in Adelaide and are passionate about error coins.

Posted in Error Coins

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