PART V. Planchet Errors:

Struck On ‘Aluminum’ Feeder Fingers

Definition: A coin that is struck on a feeder finger.  For U.S. coins, only aluminum or aluminum alloy feeder fingers are known to be involved.  World coins have been struck on feeder fingers of many different alloys.  U.S. coins are struck on “breakaway” feeder fingers that are designed to break off if struck by the dies.  Coins struck onfeeder fingers can represent a strike on what was an intact feeder finger or a strike on a feeder fingerfragment that broke off shortly before the strike was delivered

This 2007(?) John Madison dollar coin was struck twice on aluminum feeder fingers.

PART X. Wastebasket / Composite Categories:

Ghost Images:

Split Plating Afterimage

Definition: This uncommon effect is restricted to double-struck copper-plated zinc cents.  It is most often associated with off-center uniface strikes and generally is found on the die-struck face.  During a second strike, tensile stresses are magnified along the sharp sides and corners of first-strike design elements.  If the plating is somewhat thinner than normal, it can stretch to the breaking point, exposing the underlying zinc.  The exposed zinc will record the presence of first-strike design elements that have otherwise been obliterated.

This copper-plated zinc cent, struck sometime in the 1980-s, takes the form of a flipover double strike.  The second strike is off-center and uniface (struck against an underlying planchet).  The die-struck obverse face of the second strike displays a split plating afterimage of the reverse design.  The afterimage consists of the letters ERICA and the right side of the Lincoln Memorial

PART IV. Die Errors:

Collar Cuds: 

Rotating Collar Cud

Definition: Collars sometimes do rotate and this movement can only be detected if there is an imperfection in the collar that leaves a blemish on the edge of the coin.

In the July/August 2003 issue of Errorscope, William (“Ed”) Eubanks provided the definitive study of a rotating collar break (specifically a collar chip) on a large series of 2002-P Kennedy half dollars. In a sample of 261 half dollars, Ed showed the collar chip steadily rotating clockwise through a full 360 degrees. He tracked its movements across 9 die stages and 3 die pairings.

Note: The circumstances and mechanisms that lead to collar rotation remain obscure.

PART IV. Die Errors:

Collar Cuds: 

Retained Collar Cud

With this type of collar break, part of the collar breaks off but does not fall away. Instead,  it remains close to the intact part of the collar. It may be that the hardened working face of the collar breaks off and sinks into the surrounding softer metal.  Or it may be that one side of the collar breaks away but is held in place by bolts or clamps or whatever anchors the collar to the press frame.

Although it’s sometimes difficult to distinguish from a bilateral split collar, there are some telltale diagnostics. A bilateral split collar shows only horizontal spread. This creates a raised nib at both poles (see bilateral split collar),
but the curved outline of the coin is largely undisturbed except for the fact that the original circle is converted to a modest oval. With a retained collar break you look for evidence of vertical movement, horizontal offset, or pivoting – something that indicates unusual mobility in part of the collar. Diagnostics to look for are as follows:

1. Evidence of collar contact on both sides of the break at one or both endpoints. Collar contact will be seen along most of the edge that lay adjacent to the mobile side of the collar.
2. A step-up at one endpoint and a step-down at the other endpoint. This may indicate a pivoting movement of the detached portion of the collar or it could mean the presence of horizontal offset (a sliding movement in the direction of one endpoint). Both patterns of movement can of course be present.
3. A partial collar “step” that occupies a different height on either side of the break. This indicates vertical movement.
4. A partial collar that slopes down (or up) on one side of the break at a different angle from the other side of the break. This indicates the presence of tilt on the loose half of the collar

Depicted below is a 1973-D cent with a retained collar break on the right side. With diagnostics 1 and 2 present the endpoints are 180 degrees apart and can be seen at 1:00 and 7:00. There is clear evidence of collar contact on either side of the break at the upper endpoint, and clear evidence of collar contact along much of edge along the right side. There is a step-up at 1:00 and a step-down at the 7:00. It’s probably indicative of horizontal offset since expansion on the right side is symmetrical. Pivoting is associated with uneven expansion that’s greater toward one endpoint. A collar chip lies along the right side of the break at the 1:00 position. It extends from one rim to the other.

PART II. Die Varieties:

Repunched Mintmark (RPM)

Definition: A repunched mintmark variety is generated when the letter punch that is used to punch the mintmark into the working die leaves two or more offset impressions.  The impressions almost always overlap.  A totally separate secondary mintmark is a rarity.

The secondary mintmark is usually thinner and smaller than the normal mintmark.  This is due to the fact that the apex of the raised letter on the letter punch is narrower than the base.  In other words, the raised letter on the letter punch tapers in vertical cross-section.

Repunched mintmarks can reflect any of the following mishaps:

PART IV. Die Errors:

Cuds:

Retained Cuds (with horizontal offset)

Definition: A retained cud is a piece of a die that breaks off completely but is held in place. Retained cuds of the anvil die are held in place by the collar while retained cuds of the hammer die are presumably held in place by the bolts that secure the die in its recess. Retained cuds of the hammer die are much rarer, as die fragments tend to fall out with the assistance of gravity.

In order to diagnose a retained cud, one needs to see vertical displacement and/or horizontal offset. Vertical displacement simply means that the die fragment sinks in below the level of the die face, leaving the coin’s design sitting on a corresponding plateau. Horizontal offset means that the fragment slides along the break, leaving contiguous parts of the design out of alignment with each other on either side of the break.

Depicted below are close up images of a Columbia one centavo with a retained cud. While there is more going on here in addition to the horizontal offset, it is our focus for this illustration.

PART IV. Die Errors:

Cuds:

Retained cuds (with vertical displacement)

Definition: A retained cud is a piece of a die that breaks off completely but is held in place. Retained cuds of the anvil die are held in place by the collar while retained cuds of the hammer die are presumably held in place by the bolts that secure the die in its recess. Retained cuds of the hammer die are much rarer, as die fragments tend to fall out with the assistance of gravity.

In order to diagnose a retained cud, one needs to see vertical displacement and/or horizontal offset. Vertical displacement simply means that the die fragment sinks in below the level of the die face, leaving the coin’s design sitting on a corresponding plateau. Horizontal offset means that the fragment slides along the break, leaving contiguous parts of the design out of alignment with each other on either side of the break.

Depicted below is a quarter with a retained cud in the NW quadrant. There is marked vertical displacement of the retained cud because the die fragment sank in below the plane of the die face.

Part VI. Striking Errors:

Strike Clips:

Elliptical Strike Clips

Definition:  A coin that assumes an elliptical shape as the result of being sheared in two or torn off during the strike.

Elliptical strike clips can be generated on a first or second strike and can be produced in several ways.

A much larger elliptical strike clip has reduced this undated cent to a small oval.

This 1956 Chile 1 peso coin takes the form of a very small, very light (0.1 g) oval.  It is a uniface elliptical strike clip pinched off during the strike.  It was erroneously slabbed by NGC as a “struck fragment”.

More information on elliptical strike clips can be found in the August 25, 2008 and April 5, 2010 issues of Coin World.

PART IV. Die Errors:

Cuds: 

Crescentic Cud

Definition: A relatively uncommon form of cud is the crescentic cud. As the name implies, a crescentic cud is long and thin, and follows the curvature of the die. It results when the outer margin of the die neck breaks away.

Crescentic cuds reflect the presence of a circular or semi-circular zone of weakness somewhere near the periphery of the die neck.  Contributing causes may include improper heating, cooling, tempering, or quenching of the die.  This creates a boundary zone across which the hardness and brittleness of the die steel changes abruptly.  Under stress, the outer part of the die neck would tend to crack and break off.