Recently in Error Coins Category

1946 Shilling Double Struck

Compared with how many coins are minted in a production run, the rate of error is quite small. We've spoken about double errors before and they are very rare coins to have in your collection.

The coin shown is a very interesting example. On first glance it looks like it may have been tampered with to produce the features that is has such as a wide flat flan and distorted lettering.

On closer inspection this however is not the case. This 1946 shilling was struck as any coin would be. The coin failed to exit the press but was pushed up out of the collar. It was struck again, this time out of the collar. Now it was this second strike that did the damage and left the clues to how this coin was made. There is edge milling present indicating it was once struck within the collar as normal. The rim beads show evidence of being smeared outwards when the coin was struck out of the collar which has resulted in the pancake like flan typical of an out of collar strike.

The ram and portrait are well struck with no damage further disagreeing with with any post mint damage scenario. The legends are however a different story. The reverse shows clear doubling of the letters indicating the second strike at a very slight rotation. The obverse shows distortion to the lettering this time making them thinner, the second strike obliterated the width to the letters because of the slight rotation. This is a common indicator of a double struck coin.

Reverse letter doubling, doubling on top of horn and star distortion due to the second strike

Obverse letter distortion and rim beads smeared outwards during the second out of collar strike

2005 $1 Mistrike pulled straight from a Security Bag

We've recently discussed how new coins are handled and distributed from manufacture at the Royal Australian Mint through processing at the security companies and then delivery to clients such as banks and supermarkets. Based on these processes we're now able to discuss how manufacturing errors might be released into circulation or how they might be caught up in the system.

For bulk circulation coinage once the coins leave the coining press there are no processes for quality control to find any imperfect or error coins before leaving the Royal Australian Mint.

It's up to security companies who handle the bulk coin to "come across" any problem coins in the system. This is much easier with coin rolling machines as any coins of incorrect shape or size are quickly fed into a reject box and the system continues to operate.

With the batcher machine (explained in the previous article) which feeds the coins into bags a mistruck coin will stick onto the rail of the batcher. The machine ceases to run but as the operator opens the door the coin may just run into the small bag because the belt continues to move momentarily. Once the bags are sealed there are no other checks (except for the odd bag that is weight/face value checked) and the coin will happily pass into circulation. Is this how the dramatically double struck $2 coins passed into circulation?

The weights of new coins are a huge headache for security companies. The manual checks of the weights of the bagged new coins can differ dramatically. One dollar coins can often weigh somewhere between 8 and 9 grams when 9 grams should be the exact weight. This can escalate into 60 grams per $100 and then 6-8kg per pallet which is a 6% error rate. Not acceptable when you're talking about money! This is the result of poor quality blank manufacturing procedures at the factory who the RAM buys their coin blanks off, Poongsan in South Korea. We've seen mistakes that have originated from there with a one dollar coin passing through the system into circulation.....struck on a bimetal planchet!

If the problem coins are detected in these processes what happens next? Well if they aren't appropriated by staff or sent back to the RAM then they are sent interstate to a company which refunds the security company the Australian dollar equivalent or the scrap metal equivalent. This company still receives 1c and 2c pieces which are paid approximately double the face value for their copper content.

So it's really looking quite promising that on your next trip to the supermarket you could be heading home with a mistruck coin in your pocket!

As published in the Australasian Coin and Banknote Magazine August 2010.

Written by the www.australian-thereepence.com/blog team with thanks to John Mulhall for getting it to print!

Lot 401 in Downies Auction 303 held in November 2009 was a double struck 2008 $2 error coin. The lot realised $1550 (plus buyers premium) and was in lovely almost uncirculated condition with the second strike overlaying the first by about 40%. As keen followers of the decimal error market this coin was the first double struck $2 that had become available in at least the last 5 years. We found the error to be remarkable given the scarcity of $2 coin errors, which we've found to be the least common error coin among all denominations in the decimal series. The reason for this isn't really known but possibly the answer lies in the lower mintages of the $2 coin.

To our surprise early this year another double struck 2008 $2 coin appeared on eBay being sold by a coin dealer from Sydney. That coin, graded as extremely fine or perhaps a little better sold for $865. An image of this coin can be seen in Figure 1. This coin was followed just a couple of weeks later by another 2008 double struck coin being sold by a well known Sydney dealer via mail order for $1000. We quickly contacted the dealer interested in purchasing the coin but it had sold in a very short time frame. So interestingly 3 of these double struck coins had appeared on the market in just 4 months!

Fast forward to March 2010 and yet another double struck $2 coin appeared on eBay being sold by the same seller as the first eBay coin. However, this one was a 2009 coin, had two clear dates of 2009 visible and was yet again graded as EF to AU. See Figure 2 for an image of this coin. This coin sold for just a touch over $800 and appears to be the best example sold to date. A 5th and (to date) final double struck $2 was listed by the same eBay seller/dealer in June 2010, this one was a similar grade to all the others and was a bargain for the purchaser, selling for just $455 (see figure 3).

Figure 1

Figure 2

Figure 3

What is a Double Struck Coin?

Double struck coins can take a few different forms, but the most common usually has a second strike that is rotated and off-centre from the first strike by a certain percentage. The double struck $2 coins we've discussed here are all off-centre around 60-70%. They've occurred when a coin is struck and then fails to clear the coining chamber completely before the next strike occurs. This results in a second strike partially obscuring the first. The coin may rotate as it partially exits the press resulting in different parts of the coin design overlaying the first strike. The second strike almost always results in the coin taking on an irregular shape (i.e. no longer round) because it is not constrained by the collar. This would mean that the coin would likely foul coin counting machines and vending machines while still weighing exactly same as a normal coin. From an error collectors point of view double struck coins with two visible dates are the most desirable examples.

Where did the Coins Come From?

We've heard a couple of theories about how these errors reached the collector market. The first is that the coins were 'mint sport' of the type similar to double obverse or double reverse coins minted in the 1970's. According to this theory the coins would have then been spirited from the mint and released onto the market. Upon showing one of the imaged coins to well known numismatists and error experts it was suggested that given the current setup of presses at the RAM and increased security to prevent theft from the mint that this first theory is more or less implausible.

The second (and much more likely theory) is that these errors occurred in the normal production process and were bagged up automatically by the mint's highly automated systems into mint bags before being released to security companies for rolling or bagging and subsequent distribution. We could then postulate that the highly irregular shape of the double struck coins caused them to be rejected by the security companies rolling or counting machines. The errors then somehow escaped the security company and ended up in the hands of a couple of dealers in Sydney. Given that 4 of the 5 coins to date have been sold by Sydney based dealers we can only assume that most of these errors have been sent to security companies in that area.

What Next?

Will any more of these errors appear? Clearly something has changed at the Royal Australian Mint to allow these errors to escape. Whatever has changed, it has only happened in the last year or two as we're aware of no earlier examples than the first two 2008 coins. Perhaps more $2 double strikes will appear and it will be intriguing to see if any other denominations might appear. A double struck $1 coin, for example, would be a holy grail for the authors, two of the keenest decimal error collectors we know!

2009 Citizenship $1 Die Cap

Above is an example of a type of coin error known as a die cap. This particular coin is on display at The Royal Australian Mint in their First Floor display area showing visitors some of the types of mishaps that can occur to coins or the equipment during production.

This coin is a Citizenship One Dollar which was the mintmark NCLT dollar issue for 2009.

A die cap is a spectacular error coin indeed because it is the "parent" coin to potentially many, many brockages that may escape the mint. The die cap error occurs when a struck coin fails to exit the press and adheres to the hammer or moving die (which in the above error was the reverse die). The side of the die cap which was struck by the anvil die (which in the coin above is the portrait of the Queen) then starts striking subsequent coins rather than the die itself. This means that the next blank fed into the press will have a mirror image of the anvil die design struck into one side of the coin, this newly struck coin is now known as a brockage. The die cap, which is still stuck to the hammer die will continue to strike brockage coins and will become more and more dished in shape until it finally breaks free of the hammer die and exits the press. In extreme cases it has to be physically removed by mint staff when they notice a problem which is probably how the above example was found. As the sides of the die cap work their way up the sides of the hammer die it takes on the form of a 'bottle cap', which is another name that the die cap error is sometimes known by.

As the die cap strikes more and more brockages the more and more distorted the face of the cap will become, and the quality of strikes to the brockages will be come worse and worse. Brockages struck soon after a die cap adheres to the hammer die with a well formed mirror image strike are known as 'early state' brockages. Those struck by a die cap with a largely obliterated design on the die cap face are known as 'late state' brockages and their mirror image strikes are pretty much unrecognisable.

Stuart Devlin's Mob of Roos Australian One Dollar design featuring a Rabbit Ear

Since the introduction of the one dollar coin in 1984 a weak spot on reverse die for the the 5 mob of roos design has resulted in a variety of the dollar coins which you might find in your change. Because of the common weak spot on the die of the mob of roos design in some years a die chip of various sizes and slightly different locations has occurred and cuds are formed on the resulting struck coins.

The very top roo on Stuart Devlin's design may appear to have a small cud on the ear, we might call this a "flea ear". Increase the size of this flea and we have what collectors term the "rabbit ear". These rabbit ears vary from small to huge. A rabbit ear that has disengaged from the ear and occured further down the roos back is affectionately termed a "backpack or rucksack" roo. Die weakness has also shown itself at the top most roos mouth causing a "spew roo or spitting roo".

A cud can occur anywhere on a coin design where a failure of the die has occured and a part broken or chipped away. Cuds have also occured at the base of the tail on the left hand roo causing a "double tail". It is quite common for coins to have rim cuds which are really the same type of error as we're talking about here.

These errors tend to appear on some years more than others. Is this because of a larger production run or a lower number of dies in use for a particular year and therefore there is pressure on the die to stay intact for a longer run of coins? No-one is really sure and after 26 years in production this error continues to occur on the mob of roos dollar coins.

Rabbit Ears can be found only in particular years, notably 1984, 1985, 1994, 1998, 2000, 2006 ,2008 and 2009 in various sizes and positions. Collectors have noted the spew roo occurring mostly in 2006 but it has been found in other years, with the spew and rabbit occuring on some coins at the same time.

Close-up image of a large Rabbit Ear

Australia 1951 Penny Flip Over Double Strike Error

In a couple of past entries we talked about double struck coin errors and rotated double struck coin errors. An additional type of double struck coin error is the 'flip over double strike'. This error occurs when a previously struck coin somehow returns to the coining chamber and is re-struck with the previous obverse struck by the reverse dies and the reverse by the obverse dies. This could happen in two different ways, a coin could fall back into the coining chamber immediately after being struck or perhaps a struck coin coin could somehow end up back in the supply of blank planchets being fed into the coining press.

Above you can see an Australian 1951 Penny (with an unfortunate carbon spot) that is a flip over double strike error. The 'obverse' of the coin shows the portrait of George V, however, if you look closely you can see the numerals of a date in the top of his hair, a roo's tail leading backwards from his ear, and the forelegs of a roo in the hair behind his ear. You can see these forelegs in the detail image below.

Detail image of obverse showing roo's forelegs behind Kings ear

The reverse of the coin is a little more spectacular with the King's nose and mouth from the first strike clearly visible above back of the kangaroo. The ghosted image of the top of the King's head runs from the bottom of the kangaroo's back leg in a curved arc around and through the date ending up in the tail. Where it meets the tail you can see the forehead of the King. Below is a detail image of the top of the roo's back showing the King's nose and mouth.

Detail image of reverse showing Kings face above roo's back

50c Ramstrike

A Ramstrike error is caused when the planchet is sitting off-centre or out of alignment with the collar die in the press as the coin is struck. It usually results in a high lip error on the coin but produces a particularly spectacular result when it occurs on a dodecagonal coin issue such as the Australian 50c coin.

This error occurs when the 12 sided blank fails to correctly engage in the press and is struck slightly out of alignment (rotated). This incorrect alignment in the collar die results in a coin struck with protruding metal lugs which can be seen as often sharp, pushed up edges on the coin. Quite a spectacular error when seen in hand.

This error can be mislabelled by dealers or sellers not familiar with this tpe of error as a "scalloped edge" error which is the term for a different type of coin error altogether.

1982 Commonwealth Games 50c Ramstrike

We were recently contacted by a puzzled reader who, upon checking his eBay purchases recently seems to have come across a The Last Anzacs one dollar with a B mintmark that is dated the year 2000 and not 1999.

We can see from the 1999 and 2000 issues and mintages table that the mintmark dollar release for 1999 was The Last Anzacs one dollar. Mintmark coins for Brisbane, Melbourne, Adelaide and Sydney were produced at the Royal Australian Mint who also took their portable press to the show and visitors had the chance to strike the mintmark onto their own coin for $2.

The 1999 coin was also available to be struck with a C mintmark on the gallery press at the RAM and also released without a mintmark in a dual set with a Year of Older Persons one dollar.

In 2000, the same coin without a mintmark but with the date 2000 on the obverse was released in the form of a PNC. One thing to note if you are looking at Greg McDonald's Australian Coins and Banknotes catalogue is that there is a publication error and it incorrectly pictures a C mintmarked coin, this coin was issued without a mintmark.

So was a 2000 obverse coin struck with a mintmarked reverse?

How true is this story? I can only speculate as not having viewed this coin in person but it's quite possible that this has occured and this coin exists. Why not have a look at your mintmarked 1999 The Last Anzacs one dollar coins and see if there are any more of these accidental coins out there. We'd love to hear from you if you've found one!

1999 Last Anzacs Dollar -now imagine a 2000 dated coin with a mintmark!

If you're a regular reader of this blog you'll know that we've written a comprehensive series of articles on many of the different types of error coins. You may also remember that we've written a few articles on fake coin errors like this one on double headed coins and this one on creating your own fake error coin. Well in the spirit of exposing fake coin errors for what they are (fakes) here's another one that's popped up a couple of times in the last month on eBay. You can see these 'one dollar coins missing one side' below.

Now firstly let me say that genuine one sided coins most certainly do exist, and the correct numismatic term for these is 'uniface' coins. They are quite well known in Australian numismatic circles because one of the most desirable pre decimal coins one can acquire is the 1937 uniface pattern florin of 1937. It just so happens that one of these sold in the last week or two in the International Auction Galleries Auction 71 for $152,000 plus buyers commission. So uniface coins do exist, so let's think for just one minute how these might be manufactured. Staff at the mint would deliberately need to install a single die with the coin design into one side of the coin press and another die that is completely blank into the other side. Insert a blank planchet, strike the coin and hey presto you have a uniface coin. So as you can see it is a very deliberate exercise on the part of the mint and not something that can happen 'accidentally'.

But wait, I hear some of you saying what happens if two blanks happen to enter the coining chamber at the same time, are perfectly aligned and struck? Well this would result in two uniface coins too, but there would be some tell tales for these especially for Australian dollar coins. Firstly one or other of the coins probably wouldn't engage properly and you'd either have no rim graining or partial rim graining. The other indicator would be extremely poorly formed rims on both coins. Australian dollar blanks are pre-rimmed and as you can imagine the raised rims of two blanks pressing against each other while being struck would flatten the rims considerably. I should say here while I can accept the possibility of two coins being in a coining chamber at the same time I think the chances of them being so perfectly aligned that some sort of indent error doesn't occur is so minuscule that it hardly bears thinking about. But in the interests of completeness I do mention the possibility of such an error occurring.

In either case, whether it be a deliberately mint produced uniface coin or an accidental uniface coin what would each 'error' weigh? Well if it was a dollar coin it would be 9.0g, the mass of a normal dollar coin. So, now we have two indicators of what constitutes a genuine uniface dollar coin error, firstly it will weigh the correct amount, secondly if it is a genuine accidental uniface error then it should have poorly formed or damaged rims. So let's take a look at the coins above. Both have perfectly formed rims. Wow, they must be deliberately produced uniface coins! So what do they weigh? Well what does the seller on the left say when asked the weight of his coin?

"Sorry no scales"

What does the other seller say?

"I don't have any scales but it feels the same weight as a normal coin"

Hmmm, no scales. What's to stop them going to a jeweler and asking to have these coins weighed? Well nothing of course, nothing at all. So clearly neither sellers have the interests of the buyers in mind and probably have something to hide. The coin on the left has a major red flag that should scare off any potential buyer, you can CLEARLY see concentric circles on the blank side of the coin. This is a clear indicator that this coin has had the design skimmed off by a lathe or mill. This coin is clearly not an error and anyone paying more than one dollar on it is simply throwing their money away.

But what about the coin on the right? There's no tool marks on that is there? Well honestly that doesn't mean anything, tool marks can easily be burnished out by a competent machinist. But for the sake of argument let's just consider for second that this coin really does weigh 9g, this seller really has found a uniface coin! Amazing! In 2004 (because the seller says it is a 2004 coin but never actually shows you the obverse in the auction so you can't tell) the mint deliberately made a uniface coin and somehow it got out of the mint and this person obtained it! That's just amazing! Find of the century! Sadly no, in 2004 the RAM made 50,000 uniface dollar coins to proof standards and put them in the 2004 proof sets but not before sticking a pretty hologram mob of roos design on it. Break one of these 2004 proof sets up, apply a bit of acetone to the dollar coin (like we did here) and you have a uniface 2004 proof dollar coin. Of course the seller doesn't want us to know it's a proof (and never actually shows the obverse for anyone to see) and not an error coin at all, just post mint damage.

So if you see a uniface coin for sale what lessons should you take from this?

1. Ask for the mass of the coin, if the seller doesn't have scales tell them to take the coin to a jeweler and have it weighed to the nearest 10th of a gram. If the seller refuses or stalls don't walk away from the coin, run!
2. If the blank side of the coin shows tool marks AND the coin mass is unknown run away even faster! I should say here that the presence of tool marks doesn't preclude a genuine coin, the 1937 uniface florins show tool marks from the blank reverse die.
3. As in any potential coin purchase demand to see images of both sides of the coin before committing to purchase, if the seller refuses or stalls walk away.
4. Do your research, 5 minutes of work would have revealed that in 2004 the proof set contained a pad printed coin issue. It's your money, if you're not willing to spend some time making sure it's spent properly then why should anyone else?

So the coin on the right sold for nearly $500 and the coin on the left has been bid up to $30 or so as this article was written. The seller of the coin on the right has gotten away with numismatic murder and the seller of the coin on the left is bottom grubbing in the worst way by trying to cash in on some people's ignorance. If you had any doubts of this just take a look at the two ebay auction titles:

Coin on right (first coin sold)
"1 Dollar ERROR Missing OneSide!! Estate Sale On Coins!!"

Coin on left (being auctioned right now)
"1 Dollar ERROR Missing OneSide!!"

Note the spelling an capitalising, exactly the same. Awful behaviour. That's all I have to say on these 'errors', don't bid on them, don't buy them, don't support such behaviour by these sorts of sellers.

1964Y Penny Struck Through Wire or Cotton

The strike through or strike thru error term is given to an error observed on a coin where there is an incuse marking on the coin that looks as if there was something on or adhering to the coin surface at striking. This might me a piece of wire, metal or a piece of string or grease or some other foreign material. On occasions the foreign matter may still be stuck to the coin!

During cleaning or maintenance of the coin press, oil or grease needed to maintain the presses mechanical activity may get onto the surface of the die. If a coin is struck though oil then the resulting coin will have the appearance of a missing piece in the design or a poorly struck surface. It is also termed filled die or struck through grease filled die. This is often more impressive on a coin missing important features such as a letter in the date or even the entire date. The effect of a strike through oil may have the appearance that the surface (in that area) has been harshly cleaned or machined down, this is because of the texture of the foreign material and the concave impression it gives to the coin surface.

It is common to find coins struck with greasy or even rusty dies resulting in poorly struck surfaces, features or legends. This is really just poor quality control from the mints resulting in poor quality coins rather than collectable error coins. If the strike through is spectacular then expect a premium price for the coin.

196? Penny Struck Through Oil

There was an example I have seen of a strike through red cotton on the coin surface and the resulting struck coin still had the piece of red cotton attached! Fitters who work on the presses at the RAM use red rags to clean the presses and die surfaces. Seen in one of our previous articles are the fitters changing the dies on the gallery press and the red rag in use for clean up (see top image in link).