As originally published in Australasian Coin and Banknote Magazine October 2021

What Went Wrong -error coins that escaped the Mint

Image 1 – Australia 1948 Penny Struck on Underweight Planchet

Our showcased error coin this month is an error type that is a particular favourite of one of the authors. The coin in question is a Melbourne minted 1948 penny struck on an underweight 9.06 gram planchet (normal penny weight is 9.45 grams). A good part of the design of the coin is missing towards the bottom on both sides of the coin. The surface of the area of missing design is smooth on the obverse, while on the reverse it is rough with largely parallel striations going from left to right.

Why are the surfaces of both sides different? To answer that it’s best to think about the process that makes the metal strip from which the penny blanks were punched. The metal strip began as a thick heavy ingot of bronze. It was heated up and run back and forth through a series of hot roller mills with ever decreasing separation that gradually thinned out the large ingot into a flat metal strip. During this process perhaps a cooler scrap of metal falls onto the metal strip and is pressed into the surface by the rollers. It too is rolled flat and elongated but because of the difference in temperature between the scrap and the strip of metal it doesn’t actually bond with the strip.

Once complete the bronze strip is coiled and then later used to manufacture penny blanks. Perhaps at this time our bit of elongated rolled in scrap falls off of the strip and a light weight blank is punched. Alternatively, perhaps the blank is punched with our scrap in place and the punched part of scrap falls away later. We cannot be sure when the scrap fell out but we do know for certain it fell out BEFORE the coin was struck. We can be 100% sure that the scrap was on the reverse of the coin due to the parallel striations. Why then is the design missing on the obverse? Because when it was struck the planchet was too thin in that area for metal to fill the die properly.

We’ve seen several errors of this exact type over the years, few enough to make them scarce. They are an interesting item to add to one’s collection and provide a real insight into two separate processes used to manufacture coins. If you happen to see one make sure you snap it up!

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.

As originally published in Australasian Coin and Banknote Magazine September 2021

What Went Wrong -error coins that escaped the Mint

Image 1 – Australia 1988 $2 with Curved Clipped Planchet Error

If you’re even slightly active in the online coin community you’ll know that a major Australian media company published an article in early 2021 about 1988 and 1989 $2 coins. The general gist of the article was that these coins might be valuable because of the letters HH on the rib cage of the Aboriginal elder shown on the reverse. Of course, these are the initials of the coin designer Horst Hahne and they were removed from the coin after 1989. Are they valuable? Generally no, however in the image shown with this article you can see a 1988 $2 coin that is indeed quite valuable.

You’ll notice that there is a curved portion of the coin missing at the bottom edge. The curved shape is characteristic of the “curved clipped planchet error”. There was a failure during the process that manufactured the blank from which this coin was made. A failure that lead to one blank being punched from an area of a metal strip that had already had another blank punched from it, resulting in the missing part of the coin you see before you.

How do we know this is a real clipped planchet error? The technical details are beyond the scope of this article but please refer to a previous article[1] we have written that covers the topic in detail. In brief, the most obvious indicator of authenticity is the smooth flowing outward transition of the inner rim toward the outer rim on both sides of the clipped area. In particular the bottom of those HH letters flowing outward into the clip site. This is a result of unconstrained radial metal flow into the missing region of the coin.

In conclusion, what we see here is a genuinely interesting 1988 $2 coin with the HH initials on the reverse. It’s a fine example of a genuine curved clipped planchet error in an excellent grade with an unfortunate obverse fingerprint. Despite this detracting feature it is still a difficult to find error on an aluminium bronze $2 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.

[1] The Australian Coin Collecting Blog, 2012, How to Determine if a Clipped Planchet Error is Real, The Australasian Coin and Banknote Magazine, Vol 15, No. 5, pp 10-11

As originally published in Australasian Coin and Banknote Magazine August 2021

What Went Wrong -error coins that escaped the mint

Image 1 – Australia 1943I Penny Large Reverse Rim Cud Error

As error collectors the authors of this article are always on the lookout for the best examples of a particular error type, even the common and less interesting ones. One of these humble error types is the ‘cud’ error, which, according to well-known US error expert, Ken Potter, is a die break error that involves the rim or shank of the coin die[1]. Coins struck with such a broken die show missing design elements usually as blobs of metal where the die has broken. Cuds are often small and not that interesting. However, in the case of the 1943I Penny shown here you can clearly see that the cud extends around nearly a quarter of the reverse rim and protrudes well into the coin design itself.

You’ll note that the surface of the cud is smooth and flowing, which (and one of the authors is falling back onto his long past engineering degree here) is typical of a brittle fracture of the die. Close examination of the obverse design opposite the reverse cud clearly demonstrates the size and thickness of the error. The area around REX F:D: has not been struck up properly because so much of the coin metal has flowed into the missing area of the reverse die. The especially keen collector of cuds might keep an eye on each and every 1943I Penny they see looking for the same cud error. Not necessarily to find identical errors, but to find if the die break was progressive rather than a one-off-event. This could lead to a lovely group of related cud errors from the same reverse die!

In summing up the error collector should always be on the lookout for scarcity, even among common error types. If you’re looking for one cud error for your collection make sure it’s a superb example, focus on grade, size of the die break, and if possible, one that affects the strike of the coin on the side opposite the cud.

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 July 2021

What Went Wrong -error coins that escaped the mint

Image 1 – Australia 1951 Penny Flaking Flaw

Collectors of error coins would know that the most common type of pre-decimal coin error is the ‘planchet flaw’. This type of error is also known as a ‘lamination flaw’, ‘planchet peel’, or ‘lamination peel’. Regardless of the name it is caused by some sort of contamination in the metal from which coin blanks are made. Whether the contamination is some sort of gaseous inclusion or a solid impurity like sulphur or carbon the outcome is largely the same, some of the metal in the coin fails to bond correctly to the metal around it.

If this happens to occur near the surface of the coin it can lead to a ‘planchet flaw’ or a region of improperly bonded metal. Sometimes the metallic flaw has fallen off, resulting in a ‘detached planchet flaw’. Other times the metallic flaw remains attached, generally at one end and usually has a flaking appearance. In the case of the 1951 penny shown in Image 1 you can see a large boot-shaped flaking flaw covering nearly a quarter of the reverse. It stands proud of the surface of the coin and is attached on the left side at the kangaroo’s ears. See Image 2 to get an idea of how the flaw protrudes from the surface of the coin.

Image 2 – Australia 1951 Penny Flaking Flaw

Most ‘planchet flaws’ are minor, and in the case of Australian pre-decimal bronze coins, usually found on circulated low grade examples. Sometimes you’ll find one on a high grade penny or half penny, and if large enough they are nice to put into a collection. In the case of the 1951 penny shown here you’ve got the best of both worlds, the coin is a lovely high grade, and the planchet flaw is (and excuse our vernacular), a whopper. We’d be happy to say that this is among the best errors of this type that we’ve seen.

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 June 2021

What Went Wrong -error coins that escaped the mint

Figure 1 – Australia 1961 Shilling Elliptical Clip Error – Obverse

In this article we showcase an unusually shaped 1961 shilling which at first glance appears to be a cut down coin. However, close examination of the coin shows that it is indeed a genuine mint error. What aspects of the coin should you, the error coin collector, examine to distinguish this coin from a damaged one? Three key points of interest are below:

1. Examine the bases of the legend lettering near the missing areas of the coin. They should show the characteristic ‘fish tail’ appearance that is a sign of unconstrained radial metal flow. The letters TIA REGIN of GRATIA REGINA clearly show this on the obverse.
2. Do the design elements near the missing areas of the coin appear to be “falling” toward the edge of the coin? This is another sign of unconstrained metal flow. Note on the reverse how the arms of the star are bending toward the rim of the coin.
3. Look at the transition from areas of fully struck up rim to poorly struck up rim. A genuine error should show a gentle flowing transition rather than a harsh or sharp transition. The rim near D: + at the top of the obverse is fully struck and smoothly transitions clockwise as it becomes more and more weakly struck.

Figure 1 – Australia 1961 Shilling Elliptical Clip Error – Reverse

There are other elements on this coin that prove its authenticity but the three points above are the most important.

Of course we haven’t classified this error yet. There’s a clue in the shape of the coin which allows us to call it an Elliptically Clipped Planchet Error. The error has come about due to a failure in the process that punches out coin blanks from a metal strip, leading to an incomplete planchet being struck. The Elliptically Clipped Planchet Error is probably the second hardest clipped planchet error to find, and if you ever have the chance to purchase one at a reasonable price you should do so. You’re unlikely to see another one any time soon!

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 May 2021

What Went Wrong -error coins that escaped the mint

Australia 1966 10 Cent Error Struck with Upset Dies

Let’s play a game! Take an Australian coin out of your purse or wallet and hold it by the edges with your forefinger at the top, your thumb at the bottom and the portrait of the Queen upright. Spin the coin between your fingers so the tails side is facing you. What you’ll be looking at now is the tails side of the coin the right way up. That’s because Australian Coins (but not all coins) are struck in what is known as “medal orientation”. That’s just a fancy way of saying the head and tails side of a coin are the same way up!

Very occasionally obverse or reverse coin dies may not be oriented correctly when striking coins. This might have been due to an installation error, an error in the coin die hubbing process, or perhaps a mechanical failure. Coins struck from mis-oriented dies result in what is known as “rotated die” or “upset die” coin errors where the obverse and reverse designs of the coin are not oriented correctly. In the image shown here you can see one of the better-known upset coin errors in the Australian coin series, the 1966 10 cent coin.

During the production run of one pair of dies striking 1966 10 cents struck at the Royal Mint in London the obverse die was loose and rotated continually as coins were struck. As a result, upset or rotated die 1966L 10 cent coins have been found in many different degrees of rotation. This can be labelled as degrees or angles of the clockface. The error shown here is an almost perfect 180 degree or 6 o’clock rotation. You might be wondering how we know it was the obverse die that was moving and not the reverse? That’s because the edge reeding on all the upset 10 cent coins we’ve observed is fixed relative to the reverse design, but not the obverse. Which indicates a moving obverse die!

This type of error is the most easily overlooked but as a collector it’s one you can look out for and may still find in your purse or wallet even after 55 years in circulation.

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