Figure 1 Great Britain 1988 20p Obverse Rim Cud

Having been in and around error collecting for 15 years I often see the new error collector lusting after spectacular errors or varieties that are worth many hundreds or thousands of dollars. The unfortunate reality is that not all of us have large collecting budgets and we must derive satisfaction from error or variety coins that can be obtained less expensively. Figure 1 shows just such a coin. It’s a Great Britain 20 pence dated 1988 and the observant among you might note that the obverse has a large blob on the upper right quadrant of the obverse. I found this coin recently in a bag of UK currency that passed over our counter. Despite handling many thousands of coins each week I still got a thrill when I found it. When I stop getting that thrill I know it will be time to give this game away!

The blob on the rim is known as a “rim cud”. This occurred because the obverse die actually fractured and part of the design flaked away. When a coin was struck after the die had broken the metal of the planchet filled the broken area forming the cud as shown. Of course the metal that fills the cud has to come from somewhere and in the case of large cuds like this one there is usually strike weakness on the opposite side of the coin. If we consider the reverse of the coin in the upper left quadrant we can clearly see weakness in the NT of TWENTY. This area of weakness is directly opposite the obverse rim cud.

Once the die has broken every coin struck displays a rim cud in the same area. In some cases the die may continue to deteriorate and the cud actually grows and changes shape. This is known as die progression and it can be an interesting exercise to hunt out rim cuds as they grow and change shape. Personally I find this pursuit of cud progression to be especially satisfying as you know that each coin was struck with the same die pair! It’s satisfying because being able to nail down two different coins from a mintage of many millions to the same die pair is usually very difficult to do.

It’s worth talking quickly about the nomenclature of “rim cud”. There is no certain origin of the word “cud” but some suggest it stands for “Coin Under Development”. I find this nonsensical and doubt it to be true. What is certain is that generally numismatists agree on the distinction between a “cud” and a “die chip”. A “cud” is a die break that involves the shank or edge of the coin die. In contrast, a “die chip” is a die break that does NOT involve the shank or edge of the coin die and is in the middle area of the die somewhere. Those familiar with the Australian “rabbit ear” dollars should know that the so-called “rabbit ears” are not cuds, but die chips.

A version of this article was originally published in the free online coin mazazine, Independent Coin News.

What Went Wrong – Error coins that escaped the Mint

Those of you who are noodlers, or those that look closely and intently at their change will notice that quite often extra “features” can show up on a coin’s design. They appear as a coin die strikes more and more coins and wears or becomes damaged, appearing as raised lines or raised blobs. The lines are die-cracks, and (rather obviously) are caused because the coin die cracks and the coin metal fills those cracks. The “blobs” occur as bits of the coin die actually break off and the coin metal fills the new voids in the die. If the unintended blobs appear on the rim of the coin (because part of the die shank has broken) they are called “cuds”. If they appear in the centre of the coin’s design they are called “die-chips”.

Figure 1 Australia 2016 Rabbit Ear Die Chips

The natural pattern-seeking brains of coin noodlers have sometimes given descriptive terms to these die chips, a phenomenon known as pareidolia. The best known of these in Australian coin collecting circles is the “rabbit-ear” dollar. Known as such because of the typically elongated die chip that tends to form on mob-of-roos dollars. It usually forms on the top-most kangaroo of the iconic five kangaroo design, an unintended ear sitting behind coin designer Stuart Devlin’s intended set of ears. Figure 1 shows a 2016 mob-of-roos dollar with a lovely rabbit-ear die chip clearly apparent. A word of warning to the new noodler, the rabbit-ear die chip should touch the actual ear of the kangaroo and not be isolated in the middle of the kangaroo’s back! Why? Because rabbit-ear purists call that isolated die-chip a “back-pack”. Let’s not even get started on “spew-roos” and “double-tails” and “flea-ears” because those are stories for another day.

One of the most interesting things about rabbit-ear dollars is that they are not confined to one year. In fact, they have been found on numerous years. We have observed rabbit-ear die chips on coins from 1984, 1985, 1994, 1998, 2000, 2006, 2008, 2009, 2010, 2013, 2015, 2016, 2018 and 2019. The rabbit-ear die chip is different each year as each die breaks in a unique way. Figures 2 and 3 show close ups of rabbit-ears on 2016 and 2010 dollar coins and each is clearly different.

Figure 2 2016 Dollar Rabbit Ears Detail

Figure 3 2010 Dollar Rabbit Ears Detail

What does this more than 30 year of rabbit-ear die chip history tell us? It tells us that the region just behind that top-most kangaroo is clearly a weak spot that tends to crack and break as a coin die is subjected to the rigours of striking thousands of coins. One possible reason for this being a weak spot is the acute angle that the kangaroo’s ears and back form with the field of the coin. This sharp angle could be a ‘stress-raiser’, an area of localised higher stresses and strains which leads to it breaking off in time.

The really great thing about rabbit-ear dollars is that each year the Royal Australian Mint strikes mob-of-roos dollars they are potentially creating a new variety dollar to add to your existing warren of rabbit-ear dollars!

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

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

What Went Wrong -error coins that escaped the Mint

2016 Dollar Coin Struck on Ten Cent Planchet

Join with us, for a few minutes at least, as we conduct a thought exercise. Imagine a factory in South Korea that manufactures millions of coin blanks for the Royal Australian Mint. On one particular day in 2015 or 2016 that factory punches out thousands of 5.65g copper-nickel (ten cent coin) blanks that are fed via chutes into drums before being shipped to Australia. Some time during that production process one of the 10c blanks gets stuck in one of those chutes or perhaps somewhere else in the machinery and doesn’t end up in a drum with other 10c blanks. Let us now imagine that these machines change over to the manufacture of 9g aluminium-bronze blanks (for Australian dollar coins). During that production run our rogue copper-nickel 10c blank is dislodged and ends up in a drum of $1 blanks.

That drum makes its way to Australian shores where weeks or months later the Royal Australian Mint’s mighty Titan robot lifts the heavy drums with ease. These blanks are struck into 2016 Mob of Roos dollar coins in the circulating coin hall. Unknown to the operators of the coin presses, our rogue 10c blank is also struck with $1 dies and is sent out into circulation with many millions of other normal $1 coins. Maybe it’s rolled or bagged by Prosegur and ends up as your change for the Sunday newspaper! That $1 coin is different but passes through a few hands before being put aside by a sharp-eyed person and left in a drawer, forgotten for a few years. Fast forward those few years and perhaps this coin is brought into our Adelaide coin shop much to the author’s delight!

Figure 1 shows a 2016 dated dollar coin that is struck on a 5.6g copper-nickel planchet. The same type of planchet that Australian 10c coins are struck on. Did this amazing error coin result from the process we’ve described above? Well, of course we cannot know for certain but it is certainly one way it could have happened, because this type of mishap has happened before!

The legendary USA 1943 bronze Lincoln cent error occurred because “a few bronze planchets became stuck in tote bins”[1] when they were refilled with steel planchets. All 1943 Lincoln cents were supposed to be struck on steel planchets. 15-25 of these bronze Lincoln cents exist and they are worth a hundred thousand dollars or more.

By comparison, the 2016 $1 error shown here is a relative bargain, and perhaps worth a few thousand dollars. But for those few thousand dollars you would get an amazing wrong-planchet Australian error coin with lovely strike weakness around the perimeter of the design, a poorly formed rim, and the spectacular appearance of a silver-coloured dollar coin.

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

1. Coin Week : US Coin Profile – 1943-S Lincoln Cent Error Struck on a Bronze Planchet [online] 26 December 2017. Available at: https://coinweek.com/us-coins/us-coin-profile-1943-s-lincoln-cent-struck-bronze-planchet/ [Accessed 14 August 2022].

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.

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.

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].

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.