Part VI. Striking Errors:

Die alignment errors:

Horizontal misalignment:

Multiple misaligned strikes

Definition: The presence of two or more misaligned strikes on the same face of the same coin. The position of the affected die can be stable or quite unstable.

It is rare for a coin to be struck more than once by a misaligned die. It is even rarer for those strikes to be well-separated as the result of die instability. This undated India 10 rupees coin (2019 – present) features a 31% off-center first strike and a series of at least six additional off-center strikes that were all 79% off-center. The hammer die was properly centered during the first strike. However, during the later off-center strikes, the hammer (obverse) die became progressively more misaligned until it finally migrated beyond the coin. The coin showed very little movement during those later strikes and the anvil die remained fixed in position.

PART VI. Striking Errors:

Edge strikes

Definition: A planchet or coin that is struck on-edge.

Edge strikes occur when a planchet or a previously-struck coin is positioned on edge when the dies come together. The disc may enter the striking chamber spinning on its edge or rolling on its edge. It may be kicked up into a vertical position by the feeder/ejector or a neighboring planchet or coin that occupies the striking chamber at the same time. It might be caught on edge by the descending hammer die as the disc flies across the striking chamber.

In all cases, the disc is not quite vertical when struck. If it were, it would be transformed into a foldover strike.

This is a prototypical edge strike. The coin was kicked out of the striking chamber as it bent beneath the impact of the dies The two poles carry die-struck design elements while the unstruck area between them has buckled.

Other edge strikes can take on a very different appearance. In some cases, the coin falls on its side within the striking chamber in a centered, slightly uncentered, or visibly off-center position and receives a follow-up strike as the hammer die completes its downstroke. In other cases, one or both poles bend, or the metal is dragged over onto one of the adjacent faces, so that a “paraxial foldover flap” appears at one or both poles.

Part IV. Die Errors:

Deformed collar

Definition: A collar that has undergone plastic deformation. This could leave it wider than normal (a subtype of wide collar error). It could leave the collar with a sloping working face instead of a vertical working face. Reeding (if present) might be obliquely oriented instead of vertical.

Part III. Die Installation Errors:

Design/composition mismatches

Definition: High-relief designs, or designs enhanced in some other manner, may be associated with a thicker planchet or one with a different composition. This creates the potential for dies with the enhanced design to be mistakenly used to strike planchets associated with the ordinary design. The opposite situation can also occur, where dies carrying the ordinary design are used to strike planchets associated with the enhanced design.

This 1994 stainless steel commemorative 5 rupee coin carries a high-relief design normally associated with a heavier, thicker copper-nickel planchet.

This 1994 stainless steel commemorative 5 rupee coin carries the normal low-relief design.

This 1994 copper-nickel commemorative 5 rupee coin carries the normal high-relief design.

Other design/composition mismatches affecting commemorative 5 rupee coins involve one high relief die and one low-relief die on either the obverse or reverse face. These would represent mules as well as design/composition mismatches.

Part IX. Post-Strike Mint Damage:

Illicitly applied die impressions

Definition: Planchets and coins that have a new design impressed into them inside the Mint but without the use of a coining press. These illicit impressions have one or more of the following characteristics.

1) Frequent use of proof dies, normal and impaired.

2) Frequent use of proof planchets, normal and impaired.

3) Presence of odd patterns and textures.

4) One or both designs strongly misaligned (horizontally, vertically, or rotationally).

5) Design impressions often weak.

6) Multiple, overlapping impressions common.

7) Nonsense die sometimes used on one face.

8) Counterfeit die sometimes used on one face or superimposed over the original illicit die impression.

9) Oversized coins and planchets sometimes used to host the illicit impression.

10) Wrong planchet or different denomination sometimes used to host the illicit impression.

11) Heavy damage to the planchet or coin prior to, coincident with, or following upon, the illicit die impression.

12) Dies often heavily damaged or vandalized.

13) Opposing designs applied sequentially, rather than simultaneously.

14) Creation of false brockages before, during, or after application of the genuine die.

15) Raised image confined to one face.

16) Strange forms of doubling, often of an extreme nature.

This nickel planchet received two sequential impressions from either the same obverse die or two different 5-cent obverse dies. Both designs are weakly impressed and off-center toward the left. One face is rotated 90 degrees relative to the other.  Both dies were also tilted. One obverse design shows strong doubling while the other is grossly smeared. During each impression, the opposite face rested against a textured surface. One or both designs seem to have been damaged after the final impression was generated.

Depending on their provenance, how convincing they look, how much damage is present, and whether proof dies and planchets were involved, these creations can fetch prices ranging from a few tens of dollars to over $10,000.

The status of such coins as “errors” is highly controversial. Though created inside the Mint by personnel employing genuine dies, the use of techniques other than a coining press make them more like fantasy pieces.

Part II. Die Varieties:

Hidden initials and symbols

Definition: The unauthorized presence of initials or symbols tucked into a design. These are added to a working die or master die without the knowledge or approval of mint management. They are carved out or punched in by a mint engraver or other artisan. Several examples are known from Mexico, which has a long tradition of such clandestine flourishes. For example, some 1984 1 peso obverse working dies carry the tiny cursive letters “Ra” (for Rodolfo Alvarado or Rodolfo Alvarado Flores) within the collar of José Maria Morelos.

This 1974 bronze Mexico 20 centavos features a tiny engraver’s insignia “V̇” in one of the cactus pads on the reverse face. It was designed to resemble the triad of cactus spines that it replaced. The symbol is reportedly the initial of the engraver Ricardo Luna Vasco. Since this symbol seemingly appears on every 1974 20 centavos, Vasco would have altered the master die for this year. Vasco’s insignia reportedly appears on at least some working dies belonging to several other denominations, including the 10 centavos (1974 – 1976), 50 centavos (1975 – 1976), 1 peso (1974 – 1976), and 5 pesos (1974, 1976, 1977).

The working reverse die that struck this 1973 20 centavos has an inverted L and the back of a correctly-facing R hidden with the saguaro cacti. They are said to have been placed there by, or in honor of, the engraver Lorenzo Rafael.

Part VI. Striking Errors:

Indents:

External disc impressions

Definition: An impression on the underside of a broadstrike or off-center coin generated by a coin or planchet positioned just outside the striking chamber. The hammer die forces the expanded perimeter of a broadstrike or the protruding portion of an off-center planchet down onto the externally positioned disc. The result is a crescentic, half-moon shaped, or bell-shaped indentation that lies lateral to the die-struck lower face. The area above the indentation is forced upward, creating a type of forced cupping.

After a normal first strike, this 1998 cent rotated almost 180 degrees. The next strike was off-center and overlapped by two previously-struck cents. The area lying outside the second strike was pushed upward at 4:30 (first-strike clock position) by a coin or planchet lying just outside the striking chamber. A crescentic indentation runs through the first-strike letters OF AM.

After a normal first strike, this 1969-D dime was struck 20% off-center while overlain by a previously-struck dime in the northeast quadrant. Prior to the second strike, minimum die clearance increased by more than the thickness of a dime, generating an invisible strike in areas where there was no intrusive object to take up the excess space. The intrusive, previously struck dime in the northeast permitted an opposing area of die-struck design to strike up on the reverse face. An underlying coin or planchet located just outside the striking chamber at the opposite pole allowed a second-strike design rim and a few interior design elements to strike up on the side of Roosevelt’s face. The externally positioned disc generated a thin crescentic indentation on the reverse face that runs through the olive sprig. This area of the dime is tipped up slightly from the resistance generated by the underlying disc.

Part VI. Striking Errors:

“Struck-Through” Errors:

Struck Through Miscellaneous Foreign Matter:

Struck through string

Definition: A coin struck through cordage, string, thread, or some other twisted or multi-filament fiber.

The nature and origin of such “strings” is often unclear. The width, coarseness, stiffness, complexity, and composition of these strings is highly variable. However, it’s clear that some strings represent cloth that has unraveled. In some instances, the edge of a struck-through-cloth error will degenerate into a field of strings.

This 1955-D cent was struck through one or more convoluted strings that likely represent an unraveling patch of cloth.

This 1976 features a partial struck-through-cloth error. The left margin of the cloth impression shows signs of unraveling.

PART VI. Striking Errors:

Collar Deployment Errors:

Partial collar

Definition: A coin struck within a partially deployed collar.      

A partial collar error is one in which the planchet is only partially confined by the collar. The lower half of the edge shows contact with the working face of the collar while the upper half of the edge is smooth, beveled, or both.

A collar can occupy a partially deployed condition for two reasons:
1. It might have been depressed part of the way toward the anvil die face by the pressure applied by a tight-fitting or poorly centered planchet (backed, of course by the hammer die).
2. It might never have occupied a fully elevated position. Its deployment may have been blocked by a poorly centered coin (in presses where the anvil die is fixed and the collar moves up and down). Its deployment might have been interrupted for other reasons, such as debris getting trapped between the collar and the anvil die neck.

A partial collar error can be level or it can be tilted. Tilt can be so great in some instances as to leave one pole fully in contact with the collar and the other completely above the collar. The transition between the collar-struck portion of the edge and the unstruck portion can be abrupt or can be separated by a beveled interval. This zone is caused by contact with the beveled entrance of the collar. The beveled entrance can be wide, narrow, or sometimes absent. The beveled entrance often shows horizontal machining marks, which are transferred to the edge of the coin. In presses with a standard or traditional setup, the collar-struck edge is next to the reverse face (struck by the anvil die). In the inverted setup, the collar-struck edge lies next to the obverse face (struck by the anvil die). The latter setup is also called a “reverse partial collar” or a “reversed partial collar”. Uneven machining along the top of the collar’s working face can generate an undulating partial collar. When a coin returns to the collar for another strike, it often has trouble fitting back into it. It may depress the collar partway, resulting in a “re-entry partial collar”.

The edge of this 2000 New Jersey quarter dollar shows a level partial collar error with a bevel above the reeding. The bevel was caused by contact with the beveled entrance of the collar. Typical horizontal machining marks appear on the beveled surface of the coin’s edge.

This 1978 quarter dollar was struck within a severely tilted collar. The left side is fully reeded while the right side is smooth. In order to show the entire edge, the photo was taken with the coin sitting in a flashlight reflector.

This 1996-D dime shows a reversed partial collar. It was struck in a press with an inverted die setup (reverse die as hammer die).

This 1994-P dime shows an undulating partial collar. The beveled entrance was machined unevenly, so that the upper margin of the collar’s working face follows a wavy path.

PART VI. Striking Errors:

Saddle Strikes:

Inverted hump

Definition: A saddle strike in which the hump or saddle buckles toward the reverse die.

In almost all saddle (tandem) strikes, the unstruck interval between the two off-center strikes buckles toward the hammer die, which is usually the obverse die in such errors. Buckling toward the reverse die can be an indicator of an inverted die setup (reverse die as hammer die). In cents, this is a factor only for those struck after after 1996 (or possibly 1995). The earliest unmistakable evidence for cents being struck with inverted dies appears in 1997. Inverted dies appear earlier in other denominations (as early as 1992 quarter dollars). At least one indisputable example of a saddle-struck cent generated by inverted dies is known (a quad-struck 2000 cent).

The other reason for buckling toward the reverse die is a rare reversal of the usual tendency. In other words, and for unclear reasons, the hump will bulge toward the anvil die. This reversal of the usual hump direction presumably depends on the collar being in an unusually depressed position; otherwise, it will impede the growth of the hump.

This rather battered, undated cent shows a hump pointing in the direction of the reverse die. In the absence of a date or any indicator of collar location, it’s impossible to say whether the inverted hump indicates an inverted die setup (reverse die as hammer die) or a rare instance of warping in the direction of the anvil die. Both faces of each off-center strike display roughly-textured struck-through areas.

This saddle-struck quarter dollar shows a hump that points toward the reverse die. The relatively high relief and lack of detail of Washington’s head indicates it was struck long before the modern introduction of the inverted die setup. It was most likely struck in the San Francisco Mint between 1965 and 1967. Other saddle-struck quarters from this same time period show a hump that points toward the obverse die. So it’s likely that the inverted hump on this specimen is due to a rare instance of warping toward the anvil die. Very few saddle-struck quarter dollars are known, and they may represent a short-lived experiment in adapting a dual or quad press for a denomination larger than a nickel.