Error-Ref.com

You are here: Home / Search for "MISALIGNED die"

Search Results for: MISALIGNED die

Part IV. Die Errors:


Reeding vs. no reeding varieties (foreign only)

Concentric lathe lines (ES Nov/Dec 2003)

    • Various years and denominations
      • Common on the 1996-D Lincoln cent

Rusted dies (CW 12/1/08)

Excessively deep rim gutter

    • 1991 cents

Rockwell test mark left in die (hemispherical bump seen on coin) (ES July/Aug 2006)

Vickers test mark left in die (pyramidal bump) (CW 5/15/17)

Collar manufacturing errors

    • Wide collar (ES Nov/Dec 2002; CW 5/17/10)
      • Created by improper machining or improperly machined broach
      • Created by use of wrong broach
      • Improper use of correct broach
      • Widening due to wear
      • Widening due to 3 or more vertical collar cracks and associated expansion (CW 5/17/10)
    • Abnormal reeding
      • 1921 Morgan dollar with infrequent reeding
      • 1924-D Mercury dime with infrequent reeding
      • 2015 American Eagle 1/10oz gold bullion coin with narrow reeds (CW 7/13/15)
      • Low, narrow reeds caused by truncation of ridges on collar face (ES March/April 2010; CW 1/25/10, 4/16/12)
        • 1964-D 25c
        • 2008-P New Mexico 25c
          • COIN WORLD SPECIAL: article posted HERE

Hub retouching

Die retouching (CW 5/30/16, 9/30/19)

Die damage (ES Nov/Dec 2004, Jan/Feb 2003; CW 5/21/12)

    • Die dents (ES Nov/Dec 2004, July/August 2005, Nov/Dec 2005; CW 9/15/03, 12/22/14, 3/28/22, 7/31/23)
    • Die scrapes (CW 4/23/07)
    • Accidental die scratches
    • Die gouges
    • Impact scars
    • Accidental die abrasion (CW 9/8/14, 12/16/19)
    • Intentional die abrasion (“die polishing”) (CW 3/29/10, 5/31/10, 9/8/14, 3/20/23)
    • Defects related to die polishing
      • Over-polished proof and Special Mint Set dies (CW 2/21/11)
      • Trails and Wavy Steps (ES July/Aug 2006, Sept/Oct 2006, Nov/Dec 2006, Jan/Feb 2011; CW 3/8/10)
      • Localized removal of field from proof polishing (CW 2/14/2011)
        • COIN WORLD SPECIAL: article posted HERE
    • Die attrition errors (ES May/June 2003, March/April 2005, March/April 2009; CW 1/4/10, 12/24/12, 4/14/14, 11/4/19, 7/3/23, 10/16/23)
    • Other forms of peripheral die damage (ES March/April 2005; CW 8/9/21, 3/14/22)
    • Catastrophic die damage (ES March/April 2002; CW 9/15/03, 9/12/11, 9/19/11, 5/20/13, 10/27/14, 6/19/17)
    • Cancelled or defaced dies (foreign only) (CW 5/8/17, 12/31/18)
      • 1994 Hong Kong bimetallic 10 dollars
      • Egypt 25 piastres struck by defaced 50 piastres dies (CW 5/12/14)
      • 1966 Bolivia 10 centavos struck by pair of canceled dies (CW 5/8/17)
      • Chilean test dies with concentric cancellation pattern struck over struck foreign core (CW 5/8/17)
    • Rockwell test mark in die (CW 5/15/17)
    • Vickers test mark in die (CW 5/15/17)
    • Die rings (tiny rings, semicircles, crescents, and spirals)  (CW 2/20/17, 1/18/21, 6/13/22)
        • Centrally-located
        • Offset
  • Collar damage (ES March/April 2010; CW 1/25/10, 4/16/12, 6/17/19)
    • Horizontal abrasion (CW 1/25/10, 4/16/12)
    • Vertical abrasion (CW 6/17/19)

Hubbed-In debris (CW 5/27/13)

Deformed collar (CW 12/18/20)

Clashed dies (ES March/April 2002; CW 3/22/10, 4/30/12)

  • Floating die clash (collision with die fragments) (ES May/June 2002, May/June 2005; CW 7/19/10)
  • Superclash (full reciprocal design transfer) (CW 3/22/10, 10/22/18)
  • Circumferential clash marks (CW 12/10/18)
  • Grease-enhanced clash marks (CW 10/16/17)
  • Associated with weak strikes (CW 12/2/19)
  • Clashed die progressions (CW 5/15/23)

Collar clash (CW 6/11/07, 2/24/22)

Die damage with design transfer

    • Floating die clash (ES May/June 2002, May/June 2005; CW 7/19/10)
    • Floating (Type 2) counterclash (ES May/June 2002, July/August 2002, Sept/Oct 2002, Jan/Feb 2009, Sept/Oct 2011; CW 9/29/08, 12/13/10, 4/9/12, 4/21/14, 6/8/15, 4/23/18, 2/21/22, 12/19/22, 2/20/23)
      • COIN WORLD SPECIAL: article posted HERE
    • Miscellaneous and unexplained forms of design transfer/duplication
      • Some presumed Canadian counterclashes may prove to be something else

Die deterioration/deformation errors

Die breaks

Die exfoliation errors (CW 10/19/20)

Collar breaks (collar cuds) (ES May/June 2008; CW 11/22/10, 5/17/10, 11/22/10, 12/19/16)

Die cracks (CW 4/25/16)

Split dies (ES Jan/Feb 2006; CW 6/2/03, 4/10/06, 4/17/06, 6/20/2011, 5/11/15, 9/17/18, 4/26/21, 4/18/22, 7/18/22)


Green lettering – major heading

Blue lettering – linked to subject matter

Brown lettering – subject matter covered under that heading

Black lettering – no entry yet

Pivoted Die Error

PART VI. Striking Errors:

Die Alignment Errors:

Pivoted die error


Definition: Any lateral misalignment greater than 10% is likely to involve the entire die assembly.  There just isn’t enough play in the hammer die’s recess to allow this sort of lateral movement.  Even if there was, the die would surely fall out.  It may be that most horizontal misalignments have nothing to do with a loose die and everything to do with an unstable die assembly.

If major horizontal misalignments can be caused by movement of the entire die assembly, then other sorts of lateral movements are also possible.  This 1983-D nickel shows a normal first strike and a possible pivoted die error on the second strike.  The obverse die was shifted to the left about 30% and rotated perhaps 20 degrees.  While this could be a combination of a horizontal misalignment and a rotated die error, it could represent a single movement of the hammer die assembly — a pivot.

In a pivoted die error, the obverse die seems to rotate around a vertical axis that runs along the side of the die shaft and may even occupy empty space lateral to the die shaft.  In actuality, the entire die assembly is pivoting.

As described above, pivoted die errors pose a diagnostic challenge. Unless the apparent rotation is greater than 45 degrees, any potential pivoted die error can also be interpreted as a combination of a horizontally misaligned and rotated die (or die assembly). It takes an unusual error to break this impasse.

This 1996-P quarter features a centered double strike, with a clockwise rotation of the coin between strikes. The first strike was in-collar while the second strike was out-of-collar (broadstruck). This coin also incorporates a counterclockwise pivot of the obverse (hammer) die between strikes.

As expected, primary and secondary design elements on the reverse face show a consistent rotational offset around the entire perimeter.

The date shows the same rotational offset. However, at the opposite pole, the primary and secondary letters of LIBERTY show a smaller amount of offset that shrinks as one moves from right to left. The first few letters of LIBERTY show no rotational offset at all.

This pattern could only have occurred if the obverse (hammer) die assembly had pivoted counterclockwise as the coin was rotating clockwise. The axis of rotation would have been located near 6:00. Owing to the pivot, the obverse design is shifted slightly more toward the southwest than the reverse is toward the northwest.

Horizontal Misalignment Die Clash (Conventional Type)

PART IV. Die Errors:

Die Clashes:

Horizontal Misaligned Die Clash (Conventional Type)

Definition:  A conventional horizontal misaligned die clash occurs when the hammer die is laterally shifted relative to the anvil die.  When the dies collide, the resulting clash marks are also shifted laterally.

This 1989 cent shows a bold horizontal misaligned die clash on the obverse.  The clash is less visible on the reverse.  When the clash occurred, the hammer (obverse) die was misaligned toward the right.  As a result the incuse Memorial is shifted toward the left on the coin itself.  The hammer die was slightly rotated as well when the clash occurred.

Horizontal Misalignment Of The Hammer Die

PART VI. Striking Errors:

Die Alignment Errors:

Horizontal Misalignment of the Hammer Die:

Definition: This occurs when the hammer die (typically the obverse die) shifts laterally to the anvil die. The die may shift within its recess when the bolts or clamp that anchors the die in place loosen up. The entire die assembly may also shift, carrying the die with it. A horizontal misalignment can be stable or dynamic. In a dynamic misalignment, the extent of a misalignment can grow or shrink. The direction of the misalignment can also change from one strike to the next. A loose die or die assembly can oscillate in opposite directions or spontaneously return to a centered position.

 If a horizontally misaligned hammer die collides with the anvil die, you end up with a horizontally misaligned die clash. If the misalignment was towards the south, the clash marks on the hammer die are positioned towards the north, relative to the southern arc of the design rim.

 

Doubled Dies

PART II. Die Varieties:

Doubled Dies

Definition: A doubled die (hub doubling) is caused by a misalignment or a mismatch between a working hub and a working die.  The misalignment or mismatch occurs between a first and subsequent hubbing or sometimes in the course of a single hubbing. Misalignments can occur along three orthogonal planes and three orthogonal axes.  Doubled dies that are the result of a misalignment are variously characterized as rotated, offset, pivoted, or tilted.  Doubled dies that are the result of a design mismatch are variously characterized as “distended”, “distorted”, “modified” and “design hub doubling”.  A total of eight classes are recognized.

Coins struck from a doubled die will show doubling of the design elements. Doubling can be limited to one element or encompass much of the design. Doubling can be subtle or so extreme as to produce entirely separate elements of equal strength. All coins struck from a doubled die will show the same degree of doubling from coin to coin.

The correct terminology for this anomaly is “doubled die” or “hub doubling”.  No other term is acceptable.

CLASS I- Rotated Hub Doubling:

“Rotated hub doubling occurs when the die is turned either clockwise or counter clockwise on an axis near the center of the design between hubbings. It is characterized by having all devices nearer the rim doubled the most,while those near the center of the design are not doubled at all” ¹

1955-P Lincoln cent with rotated hub doubling or Class I.

Photographs courtesy of Coppercoins

1972-P Lincoln cent with rotated hub doubling or Class I.

Photograph courtesy of Coppercoins.

 

CLASS II – Distorted Hub Doubling:

“This class occurs when a hub flattens out between hubbings on a single die. This happens because the hubs are used to create a number of dies (often over a hundred). As with any malleable material, the steel flattens outward as it is used. If a die is first hubbed with a hub that is rather new and subsequently with an old hub, the devices near the outer edge will show doubling either towards the center of the design (flattened hub used first) or towards the edge of the design (flattened hub used last”.

“Class II hub doubling is most often characterized by doubling that parallels the outside edges of the  devices closest to the rim. The two primary requirements are that the spread be  directly toward or away from the rim (without rotation or pivot) and that there be clear separation lines in the doubling” ¹

1964P Lincoln cent with distorted hub doubling or Class II.

 

 Photographs courtesy of Coppercoins.

CLASS III – Design Hub Doubling:

This class of hub doubling “is caused when two different hubs with different designs are used to create one die. The design differences can be as minor as the exact placement of a single letter or design feature, or it can be as major
as two differently dated hubs.”¹

“ALL examples of what people refer to as “over-dates” in the twentieth century coin types are actually Class III doubled dies. This includes the 1918/7 – D nickel, both 1942/1 dimes, the 1943/2-P nickel, as well as others.”¹

“Design hub doubling is characterized by a difference in some part of the design rather than a misalignment of the design.”¹

A 1960 Lincoln cent proof die and 1960-D business strike working die, along with a 1970-S Lincoln cent proof working die, were hubbed with both the small date and large date hubs.

Class III: 1918/7-D Nickel                                                                   Class III: 1942/1-P Dime

 

Class III: 1960-D cent, small date over large date      Class III: 1970-S cent, hubbed with large and                                                                                                                                                                          small date                                                   

                                                                                    Photographs courtesy of Coppercoins

Class III: 1960-P Proof Lincoln cent hubbed with a small date over a large date. 

Photographs courtesy of Coppercoins

 

CLASS IV – Offset Hub Doubling:

“Offset hub doubling is caused when a die is returned to the hubbing press but is shifted to one side. The result is doubling of the design in a single cardinal direction – north, south, east, southwest, etc. This form of doubling is found more often affecting the center of the design than other classes of doubling, because regardless of the strength of the offset, all devices, including those in the center of the design, will show the same spread of doubling”. ¹

Class IV doubled die found on the reverse of the 1983-P Lincoln cent. Notice that the doubling is shifted directly to the north. 

Photographs courtesy of Coppercoins.

 

Class IV doubled die found on the obverse of a 1984-P Lincoln cent. Notice that the doubling is shifted directly to the south. 

Photographs courtesy of Coppercoins

 

CLASS V– Pivoted Hub Doubling:

“This class of hub doubling is one of the more common types of doubling. Its cause is very similar to that of Class I rotated hub doubling in that the alignment of the die that created the doubling involves clockwise or counterclockwise rotation. But in the case of Class V hub doubling, the center of rotation is at or near the rim, causing more doubling on one side of the design (the area opposite the pivot point) and little or no doubling near the pivot point.” ¹

This is a Class V doubled die found on the obverse of a 1995-P Lincoln cent. Notice that there is a well defined doubling on the letters in LIBERTY. Even the letters in IN GOD show considerable doubling while the date shows virtually no doubling what so ever. The pivot point was near the date and accounts for this feature of no doubling on the date. The black arrows are indicators pointing to die markers found on the obverse die.

 Photographs are courtesy of Coppercoins.

 

CLASS VI – Distended Hub Doubling: 

“This class is generally caused by using hubs to impress designs into improperly annealed dies. The design flattens out and becomes stretched or die tended toward the outside of the design. Like CLASS II doubled dies, CLASS VI doubled dies generally show their characteristics close to the rim.

The picture below shows a strong class VI doubled die, found on the obverse die of a 1944-D Lincoln cent. Notice the extra thickness on the bottoms of the digits in the date.

The pictures below show the same extra thickness in the motto E . PLURIBUS UNUM on the reverse die of a 1943 Lincoln cent. Notice the extra thickness in the dots and the bottoms of the letter U. This is a typical class VI doubled die. These photographs are courtesy of Coppercoins.

 

CLASS VII – Modified Hub Doubling:

“This class of doubling is caused when an errant part of the design is ground off a hub in an effort to replace it. If the errant portion of the design is not completely removed by the grinding it will leave its mark on any die created from the hub. The errant element is usually a digit or digits of the date, but it can be other parts of the design.” ¹

While modified hub doubling is an actual class, there is no substantiated evidence to prove that any examples of this class of doubling do exist. Any modification to a working hub that would show the type doubling described above would appear on numerous working dies and this has not been the case. It would also be senseless for the Mint to modify a working hub, use that hub to impress just one working die and then retire that hub; there has been no evidence to support that occurrence either. While there are various listings which have some Class VII doubled dies, there is no consensus between those various listing as to which particular dies are actually Class VII.

With the ambiguities surrounding this class of doubled dies, we shall not attempt to show examples of what this doubled die may appear as. However, we do support the definition of this class in hopes that a verifiable example
can be found.

 

CLASS VIII – Tilted Hub Doubling:

“Tilted hub doubling occurs when a die is set in the hubbing press tilted and rotated clockwise or counterclockwise from the hub. The resulting doubled die will show doubling on part of the design close to the rim, and the rest of the
design will be normal.” ¹

Again, some ambiguity surrounds this class of hub doubling. Some variety experts have included the tilted hub, instead of solely the tilted die, as the cause for this type of doubling. In this scenario the tilted hub accounts for
the majority of the single squeeze hubbed doubled dies (see Class IX) with or without a specific rotation to the hub.

A misnomer associated with this class is trail dies (including wavy steps). Some listings have this anomaly type under this class of die doubling. Our contention is that trail dies are not doubled dies and thus should not be listed under any class of hub doubling.

The photos below show a Class VIII hub doubling found on a 1964-P Lincoln cent. Notice the extra vertical bar above the L of LIBERTY and the slightly clockwise rotated second impression of the word IN.

 All photographs are courtesy of Coppercoins

.

CLASS IX – SHIFTED HUB DOUBLING:

“This form of doubling happens when a slightly misaligned (tilted) die “pops” into position under the constant pressure of the hub and its thousands of pounds of force.” ¹

 “It is most often characterized by a slippage of the design, in a cardinal direction – much like the Class IV offset hub doubling.  It most often affects centrally located design elements.  The main difference, with respect to causation, is that the design is never “picked up” off the die during the hubbing. Rather, it suddenly “slides” into place creating doubling in the design.” ¹

Once more there are some differences of opinions among the variety experts. John Wexler writes,” Class IX. God Only Knows – This class of doubling is for those doubled dies that are simply unexplained. It is for those extremely few doubled dies that defy logic and common sense. It is where the physical evidence does not support a reasonable conclusion on how the working die was hubbed to produce the secondary image.”

Those files that have the Class IX use it for listings of doubled dies that were made by the single squeeze hubbing system. However, this presents a problem for there is a grey area when the U.S. Mint used both the single squeeze and multiple hubbings to make dies. This transitional period extends from before 1986 (the first year that the U.S. Mint reported using the single squeeze hubbing system) to 1997 (when the single-squeeze hubbing was finally and fully implemented at both the Denver and Philadelphia mints for all denominations).  This time span contains a lot of doubled dies that cannot be confidently assigned to one or the other hubbing system.

Again, there are some listings in the Class IX doubled dies that contain files for trail dies(wavy steps). We feel that this is incorrect and that trail dies, including what is called wavy steps, are not doubled dies, but a different type of anomaly.

 

Notice the distortion seen in E . PLURIBUS . UNUM with extra thickness seen in the east / west plane. On early die state coins, division lines can be seen in the letters AME of AMERICA and the word OF. Also notice the split bottom serif on the last S of STATES.

These photographs are courtesy of Coppercoins

The second type of die doubling see with the single squeeze hubbing system occurs when the same offset in placement of the hub to the die occurs. Once again, the hubbing is initiated, but stopped by the press operator when the offset is detected. The the hub to die placement is correct and hubbing once again started. This start – stop – start of hubbing leaves Central located design doubling. Two examples of this type doubled die are shown below on 2004-P Lincoln cent reverse dies.

Photographs are courtesy of Coppercoins and taken by Gene Nichols.

 

Single squeeze hubbing produces doubled dies under two different scenarios. The first involves a hub that is offset relative to the die when the hubbing begins. During the hubbing, the offset is corrected by the increasing pressure that is felt on the hubbing plate, which causes the hub to slide into the correct position. Such doubled dies will have a “smeared” or elongated distortion to the design elements affected. Early die state coins will have division lines, along with split serifs, in the lettering and digits. Such an example is seen below which occurred on a 2004-P reverse die Lincoln cent.

Peripheral doubling is rare when the single squeeze hubbing system is used. The photos below show such doubling in the form of split serifs and division lines on the reverse of a 2004P Lincoln cent. The working hub had reached a point where most if not all of the design had already been transferred to the working die before the shift took place.

All photographs are from Billy Crawford.

 

Another example of single-squeeze peripheral design doubling occurs on a 2004-P Jefferson nickel, also known as the Peace nickel. Not only does the motto IN GOD WE TRUST show doubling, but also LIBERTY, the date, the star, the mint mark, the designer’s initials and Jefferson’s eyebrow.

¹ All quotations in this section are attributed to Chuck Daughtrey, unless otherwise indicated.

Die Attrition Error

Part IV. Die Errors:

Die Damage:

Peripheral Die Damage:

Die Attrition Error

Definition: This is the most recognizable and regular form of peripheral die damage.  A die attrition error is generated when a temporarily misaligned hammer die smacks repeatedly against the beveled entrance of the collar.  This wears away the edge of the field portion of the die and sometimes the entire rim gutter.  This leaves the coin with an unstruck, raised crescent on the face struck by the hammer die.  The internal margin of the crescent is smooth.  Particularly severe die attrition errors can leave peripheral letters significantly truncated.

Die attrition errors are especially abundant among 1983 cents.  A die attrition error
will only be detected after the hammer die has returned to center.

Die attrition errors are sometimes mistaken for cuds (marginal die breaks) and sometimes confused with other, more erratic forms of peripheral die damage and die loss.

The 1991-P quarter shown at upper left displays a severe die attrition error in the northwest quadrant of the obverse face.  The letters of LIBERTY are severely truncated.

The reverse face of a 1998-P quarter is shown at upper right.  The coin was struck with inverted dies (reverse die as hammer die).  The reverse face is nearly encircled by a die attrition error which is visible for about 300 arc degrees.  The attrition is most severe in the northwest quadrant.  The hammer die could have been rotating while it was experiencing a horizontal misalignment in a consistent direction.  It’s also possible that the hammer die (or die assembly) was shifting laterally in many different directions.  When this coin was struck, the hammer die had returned to center but was rotated 140 degrees counterclockwise relative to the obverse face.  The photo shows the orientation of the reverse face when the coin is flipped from left-to-right, with the obverse design oriented north.

48692990_scaled_384x351

Close-up of the word UNITED, where the tops of the letters have been lost.

48692557_scaled_352x132

Close-up showing the words STATES OF. Die loss becomes gradually less severe as you travel around the perimeter.

Bi-metallic Misaligned Center Hole

PART V. Planchet Errors:

Bi-metallic Errors:

Misaligned 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.

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.

Bi Metallic Misaligned Cores

PART V: Planchet Errors:

Bi-metallic Errors:

Misaligned Cores

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 misaligned core may occur for various reasons. Three scenarios are listed below:

(1) Center hole of ring too small, grossly misshapen or both, (too small or too misshapen to accommodate a correct fit for a correctly-sized core).

(2) An incorrectly sized core which will not fit into a normal sized center hole of the ring.

(3) An improperly inserted core due to malfunctioning equipment or inattentive workers, (even when both components are without flaw).

A 1998 Sri Lankin 10 Rupees having a misaligned core.

A 2007 Slovenian two euro with grossly misaligned core.

A 2005 Kenyan 5 Shillings with grossly misaligned core.
.

Forced Misalignments

Part VI. Striking Errors:

Die Alignment Errors:

Forced Misalignments

 

Definition: The term refers to misaligned die errors that can be linked to a specific circumstance or impact that delivered a vertical or horizontal force to the die.  Forced misalignments are most often connected to horizontal misalignments of the hammer die.

 

  1. Collar clash. When a (temporarily) misaligned hammer die smacks into the beveled entrance the collar or scrapes down along the latter’s working face, it can push the die sideways in the opposite direction.

 

 

 

This 1998-P quarter displays a horizontal misalignment of the hammer (reverse) die toward the northwest.  At the opposite pole, the design rim shows the characteristic serrations of collar clash.  The impact of the hammer die against the collar could have nudged it in the opposite direction.

 

  1. Stiff collar error. When a slightly uncentered planchet is driven into a collar frozen in the “up” position, the shear forces transmitted through the planchet can nudge the hammer die sideways.

 

 

 

This 1997-P quarter features a stiff collar error in the southwest quadrant of the reverse face, which was struck by the hammer die.  The hammer die is misaligned toward the northeast.  The slightly uncentered planchet was driven all the way into a collar that was fully deployed and frozen in the “up” position.  The shear forces generated at the site of the stiff collar error may well have nudged the hammer die in the opposite direction.

 

  1. Die attrition error.  When a (temporarily) misaligned hammer die smacks repeatedly against the beveled entrance of the collar, the edge of the field portion of the die (and often the rim gutter) is worn away.  The repeated impacts can drive the hammer die in the opposite direction.

 

 

 

This 1996 cent features (1) a die attrition error in the northeast quadrant of the obverse face, (2) a stiff collar error at the same location, and (3) a horizontal misalignment of the hammer (obverse) die toward the southwest.  The repeated impacts of the hammer die against the beveled entrance of the collar wore away the field portion of the die so that the internal margin of the planchet’s cupped, unstruck crescent skirts the top of TRUST.  These impacts probably nudged the die toward the southwest, aided by the shear forces generated by the stiff collar error.

 

  1. Indents and partial brockages.  These can nudge a die sideways, especially when combined with a stiff collar.  When an unstruck planchet or a previously-struck coin intrudes between the hammer die, an underlying planchet, and a fully deployed collar frozen in the “up” position, powerful shear forces are generated.  These can nudge the hammer die sideways.  While in-collar indents and partial brockages can be found in just about any location relative to a misalignment, they’re most often seen opposite the direction of movement.

 

 

 

This undated copper-alloy cent features a horizontal misalignment of the hammer (obverse) die toward the northwest.  An in-collar indent is seen in the southeast.

 

Weak Strikes

PART VI. Striking Errors:

Weak (Low Pressure) Strikes

Definition: A weak strike results from two proximate causes, inadequate ram pressure or insufficient die approximation (excessive minimum die clearance). Ram pressure is the tonnage applied to a planchet of normal thickness. Insufficient die approximation refers to the minimum approach the dies make to each other in the absence of a planchet.  In many cases it is difficult or impossible to assign proximate cause.  However, when a weak strike is accompanied by another error, or a weak strike progression can be assembled, the most common proximate cause appears to be insufficient die approximation.  The dies simply don’t approach each other closely enough to leave a strong impression.

Ultimate cause is virtually impossible to determine.  A weak strike could be due to a loose or cracked press frame, a loose or broken knuckle joint, a mistimed anvil or hammer die, a broken cam associated with either die, a jam-up in the guts of the press, a jam-up associated with an adjacent die pair, a broken circuit breaker, or simply dies that have fallen out of adjustment.  A weakly struck coin could also be a test piece, otherwise known as a “die adjustment strike” or a “die trial”.  Many weak strikes are labeled as such.  But unless you were there the moment it was struck, there is no way to know.  Therefore the terms “die trial”, “die adjustment strike”, “test piece”, and “set-up piece” should be abandoned.

Most, if not all weak strikes available in the marketplace appear to be the result of spontaneous equipment malfunction.  The evidence for this is abundant and manifold.

  1. These errors are far too abundant to represent escapees from a test run.  Test strikes are supposed to be set aside and consigned to the furnace for melting.  You wouldn’t expect many coins to escape this fate.
  2. If these were test pieces, then you’d expect the greatest number of weak strikes to involve the denomination that is produced in greatest abundance – cents.  However, weak strikes occur most frequently in dimes.  That’s what you’d expect of weakness caused by spontaneous equipment malfunction.  Dies that strike thin planchets have a very narrowly constrained minimum die clearance.  If the clearance grows just a little bit, the strike will be weak.  If the clearance shrinks even slightly, the dies are likely to clash.  Thicker denominations have a much more generous clearance range.  It is among these denominations that you’d expect to find fewer weak strikes, and this is indeed the case.
  3. Weak strikes can be found in association with a wide range of errors – double strikes, triple strikes, saddle strikes, misaligned die errors, clashed dies, indents, partial brockages, full brockages, struck-through errors, etc.  Given how rare escaped test pieces are projected to be, multi-error test pieces should be as rare as unicorns.
  4. On multi-struck coins, a weak strike can immediately follow a strong strike and a strong strike can immediately follow a weak strike.  Such rapid changes in die clearance (or ram pressure) would not be expected in a test run.
  5. Weak strike progressions can move in either direction – from weak to strong or from strong to weak.  Such a progression can also show an erratic pattern of strengthening and weakening.  That’s not what you’d expect of a test run.
  6. On saddle strikes, one off-center strike can be strong and the other weak.  With respect to saddle strikes on previously-struck coins, the first strike can be weak while the two off-center strikes can be strong.  The reverse situation has also been recorded.  A weak first strike can then receive a saddle strike in which one of the off-center strikes is weak and the other is strong.  None of these patterns is consistent with a test run scenario.

Weak strikes are sometimes confused with grease strikes – coins that are struck through a heavy layer of compacted die fill.  It’s actually quite easy to tell the two errors apart.

  1. A weak strike will show a poorly developed or absent design rim.  A grease strike will show a very well-developed design rim.
  2. A weak strike will retain some, most, or all of the planchet’s original proto-rim.  The proto-rim is erased in a grease strike.
  3. A weak strike will retain the beveled rim/edge junction of the  planchet.  The bevel will be lost in a grease strike.
  4. The edge will be weakly struck and relatively narrow in a weak strike.  The edge will be tall and vertical in a grease strike.
  5. Reeding will be weak or absent in a weak strike.  Reeding will be very strong in a grease strike.
  6. In a weak strike, extent and pattern of weakness will be essentially the same on both faces.  Uneven weakness is a hallmark of most grease strikes.

The photo below shows a weakly-struck 2007 Montana quarter.  It was struck on a Schuler press, a model that doesn’t even require ram pressure and die clearance to be adjusted by means of a test run.  The design rim is fairly well formed because state quarter dies have a relatively flat die face (very little die convexity).

Shown below is a 1983-D 5-cent coin with a weak second strike delivered by a rotated (25 degrees) and misaligned (26%) hammer die.

This quarter dollar was struck three times by the same die pair. The first strike was normal while the second was 40% off-center and exceedingly weak.  The third strike was 75% off center and forcefully delivered.  This specimen also illustrates the self-correcting nature of some malfunctions responsible for weak strikes.

This 2008-P Andrew Jackson dollar coin did not receive a full strike. Insufficient ram pressure (applied tonnage) or insufficient die approximation are the culprit in this case. This error is often  erroneously called “a die adjustment strike”.

Images are courtesy of Heritage Auctions