UK minted Wrong Planchet Error Coins

The Obvesre of a 1992 United Kingdom Ten Pence struck on a wrong planchet. The year and weight suggests that the planchet used was a 5 Pence planchet.

Unique chance to purchase and attribute some off-metal or struck on wrong planchet errors !

I had a great source that was willing to work with me on purchasing about a half dozen off metal or struck on wrong planchet errors that originated from the United Kingdom. These error coins were quite affordable and appear to be very scarce, so I had to take advantage of the opportunity.

How to attribute wrong planchet / wrong metal Error coins

There are a few things you will need in order to correctly attribute a coin that is on a wrong planchet.

  1. The coin. Hopefully the coin is in very good shape with limited wear. This will help in identifying the features on the coin, as well as the weight.
  2. A coin which is missing part of the design or feature. In other words, make sure that the design looks too big for the planchet size. In most cases, I will find coin designs that are too big for the planchet. Then when the coin is struck only a portion of the design is shown ( normally 50-75%). The area around the rim will typically show only part of the design or letters. You will be able to see this clearly on the examples I will list below.
  3. The Year the coin was minted. Not every coin that is struck on a wrong planchet exhibits the year. Should the year of the error coin not be present, then you may have to rely on the portraits on the obverse and reverse to give you a general idea when the error coin was minted.
  4. A magnet. One of the first things to do is to see if the error planchet is magnetic or non-magnetic. I highly suggest testing the error coin when you have it within a mylar or plastic flip so the coin does not get damaged when you try to separate the magnet from the coin. Nor do you want extra finger prints all over the coin. If you don’t have a flip or mylar handy – improvise ! You can temporarily wrap the coin in some sort of non-abrasive material just long enough to do the magnet test. Or, simply hold the coin around the rim between your index finger and your thumb and move the coin close to the magnet which should be in your other hand. Using the edge or rim of the coin place it close to the magnet to see if the planchet is magnetic. Don’t let the magnet pull the coin flat ontop of the magnet. The magnet does not have to be ultra powerful. Any magnet should work, even a weak Fridge magnet.
  5. A decent scale. You can purchase a cheap scale off of Amazon. A good one that shows to 100th of a gram (for example 1.99 grams) is ideal. Turn the scale on, make sure it is on a level area. Ensure the sale is “zeroed” and the numbers are not changing. Once the scale is stable, simply drop the coin on the scale. make sure you place the coin only on the scale. Do not leave it in a flip or mylar as that will distort the coins true weight. I suggest weighing the error coin in grams as most error coin reference sites and normal coin cataloging web sites will show a coins weight in grams.
  6. Pencil and paper. I use a pencil because I am human and I can make mistakes. I want the writing on the paper to be clear and concise, so when I go back to the paper for reference, I can comprehend what I wrote on the paper when I wrote it.
  7. A great website or other reference which can give too much information (TMI) about a coin. If the website offers a search window, you can try searching for the weight of planchets on the website. Then you have to determine if that planchet was potentially available at the same time in the mint where the coin was struck. Mints typically strike coins for other countries as well. The smaller planchets can get stuck in bins, or hoppers and they are not cleared out. Then when that area is reassigned to accept another planchet, and the dies are changed to strike another type of coin, those lost planchets are dumped into the reassigned area and find their way into the minting process and are struck with the wrong set of dies and eventually escape the mint unnoticed.

Focus on the Year, weight of the coin and metal composition

The focus should be on the planchet year, the country which struck the planchet, the weight and whether the planchet is magnetic or Non-magnetic. As you will see in the examples below, the difference in grams is pretty significant. I see people on a popular auction house/buy it now arena that attempt to convince people that since a coin is a few hundredths of a gram off, that the coin is struck on a wrong planchet. In most of those cases, the metal was not at a proper thickness when the sheets were layered or rolled which can make the metal inconsistent. That is why the US Mint and US Law have established weight tolerances and actual design specifications for minting US coins. If the coin exhibits the 100% of the design on both sides and looks comparable to another coin struck from the same year and mint, it may just be an underweight planchet.

Beware of acid treated coins

One more thing to add. If the coin looks mushy or if you look under magnification and see what I like to call empty looking ravines or the surface of the coin does not look natural, it could have been dropped in something that contains an acid. This can cause a coin to have some of its metal being eaten away, thus marring the surface and making the planchet thinner and underweight.

An Experiment, should you choose to do so.

It’s up to you whether you want to try this or not. If you do, you assume all risk. Find a coin, the best would be a cent only a few years old that is not in very good condition at all. Weigh that coin . Then, find some tomato based sauce – even some Ketchup is fine, and place that coin on a piece of tin foil or some other thing, maybe a plate. Then, liberally cover that coin with a good amount of Ketchup and walk away for a several hours, or until the next morning, then check on the coin. Rinse it off, dry the coin off with a paper towel and take it to the scale to see if the Ketchup changed the appearance or weight of the coin. I do NOT recommend using any sort of stronger chemical, especially inside a home or garage. I am not sure at what length of time it takes for this experiment to remove some of the metal, but now you know, things can happen to coins which occur outside of the mint.

Post Mint damage

People will do weird things to coins to make the collectors and attributors scratch their heads. The logic behind most circulated coins that are could be considered errors is that some of the attributors will automatically lean towards the coin having been altered after it left the mint, or dubbed “post mint damage”, meaning the coin was not in that condition when it left the mint, so the coin experienced the damage some where else.

On with attribution of struck on Wrong planchet error coins

1992 UK minted Ten Pence struck on a 5 Pence planchet.

A 1992 United Kingdom Ten Pence struck on a wrong planchet. The year and weight suggests that the planchet used was a 5 Pence planchet.
The Obverse of a 1992 United Kingdom Ten Pence struck on a wrong planchet.
The year and weight suggests that the planchet used was a 5 Pence planchet.
The Obvesre of a 1992 United Kingdom Ten Pence struck on a wrong planchet.  The year and weight suggests that the planchet used was a 5 Pence planchet.
The Reverse of a 1992 United Kingdom Ten Pence struck on a wrong planchet.
The year, weight and metal composition (non-magnetic) suggests that the planchet used was a 5 Pence planchet.

When the coin is in hand, there are two tings to note. One is that the coin is missing some of the design on both sides of the coin. The other is that there are no obvious tooling or file marks on the coin what so ever, eliminating the possibility of some one tampering with the coin.

My coin specifics

Struck in 1992, in the UK.

Actual coin weight: 3.19 grams

Non-magnetic planchet

Numista as a reference and finding a probable planchet match

After writing this information down, I went to a website called numista.com . Under the coins section, a large list of countries is offered. I navigated to the United Kingdom and Clicked on United Kingdom. In the Search field, to the left I made sure that United Kingdom was present and I type in (with quotation marks), “1992”.

The results for UK coins with a reference of 1992 appeared. I knew the weight of this planchet which is 3.19 grams. A “normal UK coin” with the weight of 3.25 grams is a Five Pence coin. This is only six-one hundredths of a gram off. A very porbable combination. The Five Pence coins were minted from 1990-1997 so the potential for this planchet being used is very probable. Here are some specifics on the Five Pence Planchet.

Five Pence coin specifics – match with my coin specifics above

5 Pence planchet – Elizabeth II (3rd portrait; small type)
1990-1997
Copper-nickel • 3.25 g • ⌀ 18 mm
KM# 937b, Sp# D4

The website assists in telling me that this planchet was non-magnetic, but the metal composition of Copper-Nickel also confirms this. So we have the the right range of years, a really close weight and the fact that it is a non-magnetic planchet, which matches the coin we have in hand.

Other UK struck on wrong planchet / off-metal error coins

Since we walked through the attribution phase with the coin above, I am not going to perform the attribution on each and every struck on wrong planchet / off metal coin listed here. I will show you the photographs, give you the probable attribution and if you desire, you can practice double checking the attribution, if you decide to do so.


1992 UK minted Two Pence struck on a Penny planchet.

Year: 1992, Weight: 3.59 grams, Metal Composition: Non-magnetic, Probable match: UK Penny Planchet (1992-1997)

Obverse of a United Kingdom Two Pence coin struck on a Penny planchet
Obverse of a 1992 United Kingdom Two Pence coin struck on a Penny planchet. The planchet weight is 3.59 grams. The planchet is magnetic.
Reverse of a United Kingdom Two Pence coin struck on a Penny planchet
Reverse of a 1992 United Kingdom Two Pence coin struck on a Penny planchet. The planchet weight is 3.59 grams. The planchet is magnetic.

1998 UK minted One Penny struck on a foreign planchet.

Year: 1998, Weight: 2.36 grams, Metal Composition: Magnetic. Attribution of this coin is currently underway.

Obverse of a 1998 United Kingdom One Penny Struck on a foreign planchet. The planchet weight is 2.36 grams. The planchet is magnetic.
Obverse of a 1998 United Kingdom One Penny Struck on a foreign planchet. The planchet weight is 2.36 grams. The planchet is magnetic.
Reverse of a 1998 United Kingdom One Penny Struck on a foreign planchet. The planchet weight is 2.36 grams. The planchet is magnetic.
Reverse of a 1998 United Kingdom One Penny Struck on a foreign planchet. The planchet weight is 2.36 grams. The planchet is magnetic.

1999 UK minted Two Pence struck on a Penny planchet.

Year: 1999, Weight: 3.59 grams, Metal Composition: Magnetic planchet, Probable match: UK Penny Planchet (1998-2008)

Obverse of a 1999 United Kingdom Two Pence coin struck on a Penny planchet. The planchet weight is 3.59 grams. The planchet is magnetic.
Obverse of a 1999 United Kingdom Two Pence coin struck on a Penny planchet. The planchet weight is 3.59 grams. The planchet is magnetic.
Reverse of a 1999 United Kingdom Two Pence coin struck on a Penny planchet. The planchet weight is 3.59 grams. The planchet is magnetic.
Reverse of a 1999 United Kingdom Two Pence coin struck on a Penny planchet. The planchet weight is 3.59 grams. The planchet is magnetic.

No Date UK minted Two Pence struck on Penny planchet

Year: Unknown, Weight: 3.55 grams, Metal Composition: Magnetic planchet, Probable match: UK Penny Planchet (1992-1997)

Obverse of a No Date (ND) United Kingdom Two Pence coin struck on a Penny planchet. The planchet weight is 3.59 grams. The planchet is magnetic.
Obverse of a No Date (ND) United Kingdom Two Pence coin struck on a Penny planchet.
The planchet weight is 3.59 grams. The planchet is magnetic.
Reverse of a No Date (ND) United Kingdom Two Pence coin struck on a Penny planchet. The planchet weight is 3.59 grams. The planchet is magnetic.
Reverse of a No Date (ND) United Kingdom Two Pence coin struck on a Penny planchet.
The planchet weight is 3.59 grams. The planchet is magnetic.

More UK struck on wrong planchet / off metal error coins on the way !

I have a few more of these UK minted error coins on the way. Should I find the time, I will add them to this post.

I hope you learned something from this post !


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