What is a Die Variety Coin?
What is a Die Variety ?
A die variety is a variation to the normal design to a coin die, usually caused by human error or defects in the preparation or maintenance of the coin dies. Varieties are typically produced on working dies, instead of on the master die. Typical die varieties include doubled dies (Doubled Die Obverse and/or Doubled Die Reverse) repunched mintmarks (RPM’s), Over mint marks (OMM) and repunched dates (RPD’s); plus a small number of other minor varieties introduced during the strike of the coin.
What is a Doubled Die ?
Doubled die is a term in coin collecting used to refer to doubling in the design elements of a coin. Doubled dies can appear as an outline of the design or in extreme cases, having legends and dates appear twice in an overlapping fashion.
Doubled die error coins can fetch significant prices when they are noticeable to the naked eye or occur in a popular coin series. A few examples are the 1955 doubled die Lincoln Wheat cent, the 1969-S doubled die Lincoln Memorial cent, the 1972 doubled die Lincoln Memorial cent, the 1964 doubled die Kennedy half dollar, the 1961 doubled die Franklin half dollar to name just a few.
In the coin world, proper terminology for this occurrence includes the letter ‘d’ at the end of the first word, hence “doubled die”. The term “double die” without the first word ending in ‘d’ is not proper numismatic terminology.
Doubled dies are created when the master die imprints an additional, misaligned image onto a working die. There are many ways this misalignment of devices can occur, which have been grouped into eight classes:
Class 1 Doubled Die, Rotated – Results when the working die receives an additional pressing from the master die that is misaligned in a clockwise or counterclockwise direction.
Class 2 Doubled Die, Distorted – Results when the master die design moves toward the rim between hubbings.
Class 3 Doubled Die, Design – When a master die bearing a different design stamps a die bearing another design.
Class 4 Doubled Die, Offset – The working die receives an additional pressing that is misaligned in an offset direction.
Class 5 Doubled Die, Pivoted – The working die receives an additional pressing that was misaligned via rotation with a pivot point near the rim.
Class 6 Doubled Die, Distended – The working die receives an additional pressing from a master die that was distended.
Class 7 Doubled Die, Modified – The master die is modified between the working die’s pressings (e.g., a design element was chiseled off).
Class 8 Doubled Die, Tilted – A working die and/or master die is tilted during a hubbing.
Doubled dies are a result of the way in which in the United States Mint dies are created. Before 1997, die pairs (hammer die and anvil die) were made by hubs that contained the raised design elements that were intended to appear on the coin. The blank dies were heated (to soften them) and then were pressed against the hubs to transfer the design from the hub to the working dies.
Often, one impression was not enough in every case to transfer the design elements from the hub to the die, so multiple impressions were required to transfer enough of the design. For this reason, after the first impression was made, the die was reheated and prepared for a second impression.
The mint workers would try to use guides to align the hub and the working die perfectly to prevent overlapping, or a doubled die.
It is when mint workers failed to align dies properly during this process that doubled dies were produced. In many instances three to four impressions were required, which could but rarely led to tripled and quadrupled dies.
In summary, after each impression, a heated working die is removed and checked to see if the entire design and its details were successfully transferred from the master die, to the target working die. A doubled/tripled/quadrupled die is created if these multiple impressions pressed onto the working die were not properly aligned. Note: you will see HUB used in place of master die in may locations - it's the same thing.
Modern coining methods have greatly reduced the number of these varieties due to the use of a single squeeze hubbing method during die creation, but doubled dies in modern United States coinage are still occurring. With this new die making process implemented after 1996, dies only require one impression of the hub to transfer all of the design from the master die to the working die. But it has been discovered that the pressure created is so great, that some working dies tend to slightly rotate during this process.
What is a Re-punched mint mark (RPM) ?
A re-punched mintmark, or RPM, is a coin that shows two or more mint marks on the same coin. This was caused by human error in the punching of the mintmark onto the coin die . Before 1990, a U.S. Mint engraver manually punched the mintmark into each individual working die. Occasionally, due to human error, a die would get two or more punches of the same mintmark, sometimes in almost the same location, and sometimes at 90 or 180 degree rotations. Some times the Mint engraver would catch these defective working dies before any coins were produced from them. A working die that had multiple punching of a mint mark would strike coins with multiple impressions of the same mintmark letter. Such specimens are called re-punched mintmarks, or RPMs. In the Coin Collecting Hobby these Repunched Mint Marks (RPM) are very collectible.
When the Mint started using mint marks (letters) in the early 1800’s to identify the various branch mints at which coins were being struck, the mint mark was hand punched into the working dies that would be striking the coins. It was the last portion of the design to be placed on the die. These mint mark letters are as follows: D for Denver, S for San Francisco, CC for Carson City, O for New Orleans, P for Philadelphia, and W for West Point.
A Mint engraver would take a thin steel rod (punch) that had the mint mark engraved on one end and hold it in place on the working die where the mint mark was to be applied. Using a mallet he tapped an impression of the mint mark into the die. In most cases it was necessary to strike the punch more than once with the mallet in order to leave a satisfactory impression of the mint mark in the die.
When the multiple mint mark impressions are from the same mint mark (a D punched over a D, or an S punched over an S), the variety is known as a Repunched Mint Mark (RPM) variety. The reference of D/D is used to refer to a “D punched over a D.” Likewise, S/S is used to refer to an “S punched over an S.” So in today’s modern coinage, the most affected mint marks with RPM’s would be the D (Denver) and S (San Francisco) mint marks as they are the mint marks most familar to the collectors.
When people describe mint mark punches, a direction may be implied the D/D or S/S mint marks, such as D/D North or D/D West. When a direction of an RPM is given, that direction refers to the direction of the weaker mint mark punches. The weaker mint mark punches were the first to be punched into the working die and did not penetrate as deeply in the working die. Eventually a stronger primary punch would be the deepest impression in the working die, completing the addition of the mint mark symbol and creation of the RPM on that working die.
An explanation of the following error coins coming soon