by Mike Diamond for CoinWeek…
On June 21, Cliff Reuter posted images of a 1983 Lincoln Cent showing the upper portions of an incuse, mirror-image TRUST between the 7:30 and 9:00 positions in the peripheral field. As Reuter himself admitted, such letters typically result from contact marks from another cent.
Indeed, a second specimen from the same roll of uncirculated 1983 Lincoln Cents shows the letters “US” (from TRUST) at the bottom of Lincoln’s lapel. These two letters are undoubtedly contact marks from the obverse of another cent. The base of Lincoln’s bust is a high point in the design, making it particularly vulnerable to light contact marks.
The field can also pick up impressions of peripheral letters if the source coin is tilted down at one pole. In such cases, you’ll almost always see a rim impression lateral to the incuse letters. Unequal pressure on the source coin can also produce unipolar contact marks within the receiving coin’s field.
Reuter was hesitant to dismiss the first specimen as simple contact marks because the incuse letters closely follow the inner margin of the design rim, which itself shows no damage. It’s difficult to envision a scenario where a source coin could impress its motto into the outermost field of the receiving coin without creating a rim impression or damaging the latter’s design rim.
Group members attempted to propose a viable scenario. I suggested the source coin was struck by a worn die, leaving it with a “ridge ring.” As illustrated by the 1988 Lincoln Cent, these peripheral bulges can be as high as the design rim, while simultaneously leaving the raised letters of “TRUST” thinned and shrunken. This curving metal bulge could theoretically press into the field without leaving evidence on the receiving coin’s design rim (Coin World, February 15, 2021).
I also suggested the source coin might have been weakly struck, resulting in a low or absent design rim.
Another member proposed that the letters of TRUST might have been on the outer edge of an off-center cent’s struck tab. Lacking a design rim, the tab’s edge could neatly fit the curve of the design rim. The same member alternatively suggested that the raised letters of TRUST could have been on the obverse perimeter of a cent with a misaligned die. In this case, again, there would be no design rim to interfere.
Reuter sent the coin to me for a closer examination, expecting me to agree with the consensus that the incuse motto was a contact mark. However, I began to question this assumption under high magnification. I confirmed that the letters hug an otherwise unaffected design rim. Furthermore, the fainter letters (“TRU”) appear to follow the field’s topography, though this might be wishful thinking. Radial flow lines extend from the field into the letters, but the letters are too faint to determine if they’ve been distorted by die wear. These observations are somewhat unexpected and suggest the possibility that the letters were present on the obverse die that struck Reuter’s cent.
The incuse letters are reminiscent of a tilted (vertically misaligned) die clash. Shown here is a tilted die clash on a 1960-D small date Lincoln Cent. The incuse letters of STATES can be seen in the field between the base of Lincoln’s bust and the design rim. Numerous other tilted die clashes have been discovered among 1960-D small date cents.
A significant problem with identifying the 1983 cent’s incuse motto as a tilted die clash is that these are obverse letters, not reverse letters. This would require the source die to have been an obverse die, resulting in a mule clash involving two obverse dies.
The only known 20th-century mule clash also involves two identical dies (reverse-on-reverse). It appears between 7:30 and 9:30 on the reverse face of a 1999 Lincoln Cent. Also a tilted die clash, it features the incuse, mirror-image letters OF AMERIC in the field just inside the design rim. Only the tops of the letters are present and cut off, indicating the source die was slightly misaligned and rotated 150 degrees. All letters are doubled, suggesting two closely spaced die clashes (Coin World, August 13 and 20, 2018).
The clashed letters on the 1999 mule clash cent are wide, as is the case with any ordinary clashed dies error. This is because the widest part of any letter recess is at the surface, which is the part of the letter recess that will contact the opposing die. Conversely, lightly-impressed, letter-shaped contact marks are typically thin, as the narrowest part of a raised letter corresponds to its highest point.
Therefore, the narrow incuse letters on the 1983 cent violate the expected appearance of a tilted die clash, mule or otherwise. However, this isn’t necessarily a fatal blow to the hypothesis. It’s possible the die responsible for the clash had narrow letter recesses at the surface. Thinned, shrunken letter recesses can develop in two ways: As discussed earlier, a deteriorated die with a peripheral trough corresponding to a ridge ring will have thin, shallow letter recesses in its floor. Thinned letters can also be produced by intentional die abrasion, as shown by a 1972-D Lincoln Cent. When a die is abraded, the field is removed, sometimes down to the deepest, narrowest portions of the letter recesses.
An abraded die is a more likely culprit than a worn die because the letters in a ridge ring trough are recessed and unlikely to contact the opposing die’s field.
Both abraded dies and worn dies with ridge rings are well-represented among 1983 cents.
A mule clash can be mimicked by an exogenous floating die clash. This is a die clash from the working face of a die fragment derived from another die pair. The illustrated 1972-D Lincoln Cent displays an exogenous floating die clash on its reverse face. The clash mark was generated by a die fragment from another reverse die. The letter traces are broad, as with any conventional die clash (Coin World, June 20, 2022).
Since die fragments are randomly positioned within the striking chamber, it’s unlikely that the curved outer margin of such a fragment would line up with the edge of the opposing die. Also, a fragment’s impression will terminate abruptly at one or both ends, as seen with the 1972-D Lincoln Cent.
It was relatively easy to dismiss other causes of incuse lettering, including: (1) a large, flipped-over, multi-element dropped filling, (2) a thin, flipped-over struck fragment, (3) a flipped-over fragment from a disintegrated die cap, and (4) a flipped-over piece of detached copper plating. In all these cases, the stray element would be expected to occupy a random position within the striking chamber, letter strings would terminate abruptly, the letters would occupy a shallow recess, and the recess itself would ordinarily have recognizable boundaries. None of these attributes appear on the 1983 Lincoln Cent.
If this is a mule clash, there’s a strong likelihood that the two obverse dies made contact outside the striking chamber. Perhaps when a worn or abraded obverse die was being removed and replaced by a new obverse die, the two dies accidentally or intentionally clacked together.
In the final analysis, while I can’t prove with absolute certainty that the faint letters on the 1983 cent are contact marks, this is by far the most likely explanation. After all, there is only one known 20th century mule clash, while there are an infinite number of coins with letter-shaped contact marks. Probability aside, the principle of Occam’s Razor also points to contact marks. Occam’s Razor proclaims that the simplest, most prosaic explanation is usually the correct one.
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