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Partial Off Center Die Caps

PART VI. Striking Errors:

Die Caps:

Partial (off-center) Die Caps:

Definition: A partial die cap begins with a coin that is struck off-center and sticks to either the hammer die or the anvil die. It is then struck into the next planchet, leaving an “aligned” partial brockage (see aligned partial brockage). Partial die caps involving the hammer die are much more common than those involving the anvil die,since the latter tend to be scraped off by the ejection finger or lifted up by the top of the collar.

This Lincoln cent is a partial die cap of the hammer (obverse) die. After it stuck to the obverse die it struck one planchet and fell off. The raised details of the reverse design are flattened and expanded from that second strike.

Off Center Uniface Stretch Strike

PART VI. Striking Errors:

Off Center Strikes:

Uniface

Definition: An off-center strike in which the coin is struck against an underlying or overlying planchet. The second situation happens less often. In either case, the face struck against the planchet is featureless; the opposite face is die-struck. In an off-center uniface strike, the entire face must be featureless. If any of it is die-struck, it is designated an off-center strike with indent.

Due to the double thickness involved in such an error, effective striking pressure is elevated. This often produces a “stretch strike” — a coin with an expanded “slide zone”.

This 1988(P) Lincoln cent takes the form of an off-center uniface strike. It shows an unusual degree of expansion, due either to elevated ram pressure or an unusually small minimum die clearance. The slide zone in this “stretch strike” is correspondingly wide.

The second strike on this 1992 cent was off-center with a uniface obverse.

Off Center Strike With Collar Scar

PART VI. Striking Errors:

Off Center Strikes:

With Collar Scar

Definition: An off-center strike will often show a collar scar on the face struck by the anvil die. A collar scar is a semi-circular groove that lies lateral to the die-struck design and the location of the design rim. The collar scar is produced when the protruding portion of the off-center planchet is forced down upon the top of the collar by the descending hammer die. The strength and completeness of the collar scar varies considerably, and a significant fraction of off-center strikes show no collar scar at all.

The above off center struck 1998-P Washington quarter has collar scars on the reverse of the coin (indicated by the black arrows).

The above undated Jefferson nickel shows a small area of where the collar indented the planchet (indicated by the black arrow).

Multiple Strikes On-Center/Off-Center

PART VI. Striking Errors:

Multiple strikes:

On-center/Off-center

Definition: Multiple strikes can be either on-center or off-center. The reasons for multiple strikes are as varied as the number of strikes that can occur. Ejection failures which prevent a planchet to correctly discharge from the striking chamber are numerous.

A 1985 10 pesos from Argentina which has been struck off-center a minimum of 17 times. This coin was highly distorted by several other planchets entering the striking chamber. Complete details of each strike were obliterated by these intruding planchets.

Edge Strike: With Off-Center Or Broad Strike

PART VI. Striking Errors:

Edge Strike:

Off-center or Broadstrike Produced by Continuation

of the Down Stroke

Definition: An edge strike is a coin struck on-edge. It may have entered the striking chamber spinning on its edge. It may have been kicked up into a vertical position by the insertion finger. It may have entered the striking chamber rolling along on its edge. Or it may have been flying through space and managed to get caught by the descending hammer die.

After initial contact, an edge-struck planchet slips and falls on its side. During this phase it is often kicked out of the striking chamber. The impact on the edge may cause the planchet to bend. The presence and severity of the bend is highly variable. The reason the planchet slips may be because it might have not have been perfectly vertical or it might have been sitting in a sloping recess of the die face that caused it to slip. In either case, folding is not complete. If it was, the coin would have been converted into a foldover strike (see foldover strike).

An edge strike can appear at both poles of an otherwise unstruck planchet. A coin can receive a second strike that also happens to be an edge strike. Sometimes an edge-struck planchet slips and lands on its side within the striking chamber. It then receives a conventional strike (centered or off-center) during the completion of the downstroke of the hammer die. The last eventuality is illustrated here by a 1986 cent.

This broadstruck 1986 cent was initially struck on-edge. The edge struck by the obverse die shows the front of Lincoln’s face. The edge struck by the reverse die shows what appears to be a distorted base of the Lincoln Memorial. In this same area, some metal was dragged onto the reverse face, creating a small foldover flap (a “paraxial” foldover strike).

After being contacted on-edge by the two dies, the coin slipped and fell on its side whereupon it was struck during the completion of the downstroke of the hammer die. The edge strike and the centered strike were therefore all the result of a single downstroke.

Cupped Off Center Strike

Part VI. Striking Errors:

Off-center Strikes:

Cupped Off-center Strikes

Definition: As is the case with broadstrikes, off-center strikes can show degrees of cupping ranging from nil to 90 degrees. In many cases there’s no obvious cause for the cupping. In other cases, the unstruck portion of the planchet is forced up by a stiff collar.

This 2000 cent shows extreme cupping with no obvious cause. The wall sticks up about 75 degrees from the horizontal. No trace of a collar scar is visible on the reverse face (the face struck by the anvil die).

The unstruck portion of this 1985 cent shows significant cupping. It was forced up as the planchet was driven past a stiff collar. This specimen is therefore a combination of an off-center strike and a stiff collar error. The collar scar is starkly obvious on the reverse face.

Broadstrike: Centered

PART VI. Striking Errors:

Broadstrike:

Centered

Definition: When a perfectly centered planchet is struck out-of-collar, it expands evenly in all directions. This error can be called a “centered broadstrike”. However, since the majority of broadstrikes are centered, hobbyists usually refer to it simply as a broadstrike. If the planchet is not well-centered, but the design remains complete on both faces, the error is called an “uncentered broadstrike”.

The failure of the collar to deploy and surround the planchet before the strike can conceivably arise from a number of circumstances and will vary depending on the press brand and model used. In the Bliss press, the collar rests on springs and remains in place while the anvil die rides up and down inside it. Debris trapped between collar and die shank can cause the collar to ride up and down with the anvil die, preventing it from occupying its normal position during the strike. While this scenario has not been proven, it is at least plausible.

The 1999-P Roosevelt dime shown above is a centered broadstrike

The 1999-P Jefferson nickel shown above is another centered broadstrike.

Broadstrike: Uncentered

PART VI. Striking Errors:

Broadstrike:

Uncentered

Definition: When a planchet is poorly centered and then struck out of collar, it ends up as either an off-center strike or an uncentered broadstrike. To qualify as an uncentered broadstrike, the design must be fully present on both faces. If the design is cut off at the edge on one or both faces, it is an off-center strike.

Various factors determine whether a poorly centered planchet ends up with some of the design cut off at the edge. One factor is, of course, how far to one side the planchet settles. Another factor is the strength of the dies’ impact. A very strong impact will cause significant expansion of the planchet and turn what would ordinarily be an off-center strike into a an uncentered broadstrike. The third factor is the coin’s design. If peripheral lettering is separated from the design rim by a significant gap, it has a greater chance of ending up as an uncentered broadstrike, all other things being equal. Likewise, if the design rim is quite broad, the coin once again stands a good chance of ending up as an uncentered broadstrike, if we control for planchet positioning and striking pressure.

The above images show an uncentered broadstrike that occurred on a 1999(P) Lincoln cent.

Bi-metallic Double Punched Center Hole

PART VI. Striking Errors

Bi-metallic Errors:

Double Punched Center Hole

Definition: Bi-metallic error coins are restricted to foreign countries. These coins may experience any of the many types of striking errors listed in the Error-Variety Ready Reference however, one must understand we are dealing with two components, a ring & a core. Any number of exotic possibilities or combinations of die varieties, die errors, planchet errors & striking errors can be found on bi-metallic coinage.

A 2004 Colombian 500 pesos. The center hole has clearly been double punched.

Bi-metallic Misaligned Center Hole

PART V. Planchet Errors:

Bi-metallic Errors:

Misaligned Center Hole

Either the punch or the solid ring planchet was misaligned when the disc was pierced. The core itself appears misaligned only because the center hole is off-set.

Two specimens are shown.
A 1995 Columbia 500 pesos with center hole misaligned.

A 1996 Canadian polar bear two dollars. The center hole is clearly misaligned.