Search Results for: lamination

Retained Lamination

PART V. Planchet Errors:

Alloy Errors:

Lamination:

Retained Lamination

Definition: A lamination error occurs when metal flakes off the surface of a coin or planchet. It is generally believed that the flaking, peeling, and cracking is due to impurities in the alloy which causes metal to separate along horizontal planes of weakness.

A retained lamination error is a flake that remains attached to the main body of the coin.

A piece of this of this 1960D small date Lincoln cent has peeled up and folded over. Another area of delaminating metal can be seen to the left of the retained lamination (indicated by white arrows).

There is little doubt that the retained piece of lamination seen on this 1959-P Lincoln cent came from the first S of STATES. The upward folded piece of lamination shows the indents of the letter S where it originated from.

The 1941-P Lincoln cent pictured to the left has a large diagonal strip of lamination that has been retained.

Images are courtesy of Paul Ihrig.

Lamination: Fold Over Before Strike

PART V. Planchet Errors:

Lamination:

Lamination Fold-over Before Strike

Definition: A lamination error occurs when metal flakes off the surface of a coin or planchet. It is generally believed that the flaking, peeling, and cracking is due to impurities in the alloy which causes metal to separate along horizontal planes of weakness.

When a lamination flake fails to detach completely and instead folds over before the strike, it leaves a “struck-through” error beneath it. Lamination flakes that break off completely and that are struck into planchets different from the ones they’re derived from are responsible for a subset of those struck-through errors designated as “struck through a fragment”.

The image above shows a 1964(P) Lincoln cent with a semi-lunar (half-moon shaped) lamination flap that lifted up from the edge of the coin and folded over onto what would eventually become the obverse face of the coin.

The 1957(P) Lincoln cent pictured above had a lamination flap fold over onto what would become the obverse face. When the flap was struck into the coin, it left a semi-lunar struck-through error beneath it. The flap broke off after the strike but was retrieved.

Lamination Cracks

PART V. Planchet Errors:

Lamination:

Lamination Cracks

Definition: Lamination errors are planchet errors in which the surface of a coin cracks and flakes. It is generally believed that lamination errors are caused by contaminants in the alloy that cause the metal to separate along the horizontal plane. Lamination errors can develop before or after the strike. They are generally restricted to solid-alloy coins. The term “lamination error” is grammatically incorrect as the metal is actually delaminating. While “delamination error” would be the proper term, we’re stuck with the terminology we’ve inherited from previous researchers.

Lamination errors are closely related to split planchets and clam-shell splits. In the latter two errors, separation also occurs in the horizontal plane, but at a deeper level.

A lamination crack is one common manifestation of a lamination error. The surface of the coin simply cracks and may lift up slightly on one side. Lamination cracks are sometimes mistaken for die cracks and split dies by novice collectors.

This 1954 Roosevelt dime shows a lamination crack crossing the President’s head.

Lamination Error: Loss Before Strike

PART V. Planchet Errors:

Lamination Errors:

Loss of Lamination Before Strike

Definition: Flakes of metal can peel off the surface off a planchet before the strike. Such planchet defects are generally attributed to the presence of contaminants in the alloy.

Lamination Loss: After Strike

PART V. Planchet Errors:

Lamination:

Lamination loss after strike:

Definition: Flakes of metal can peel off the surface of a coin after the strike. Such defects are generally attributed to the presence of contaminants in the alloy. In some instances, flakes of metal lift off the face of a coin as the result of an inadequately mixed alloy.

The 1958-D Washington quarter pictured above shows two areas where flakes spalled off the coin after the strike (indicated by black arrows).

A more dramatic and instructive example of a lamination flake that broke away after the strike can be seen in the above image of a 1944-D Lincoln cent. The floor of the depression, which was left behind by the missing flake, is quite dark and probably represents the contaminants that caused the metal to separate in the first place.

Laminations In Clad Coins

PART V. Planchet Errors:

Lamination Errors:

Lamination on Clad Coins

Because copper-nickel clad layers are already very thin, it is quite unusual for lamination errors to develop within a clad layer. Yet such errors do occur. They can be distinguished from “partial clad” errors because the copper core is not exposed in a lamination error.

A small section of metal on this 2002P Indiana Statehood quarter has peeled away and detached itself from the coin’s surface. Another area of delaminating metal – still attached – can be seen to the left of the area with the missing surface metal (indicated by white arrows).

Part V. Planchet Errors:

Alloy errors

- Improper alloy mix (CW 12/27/11, 1/30/23, 4/3/23)
  - Poorly mixed alloy
  - Incorrect proportions of metals
  - In conjunction with rolled-thick errors (1941 cents, mainly) (CW 10/15/12)
- Gas Bubbles (CW 11/19/12)
  - Intact (“occluded”)
  - Ruptured
- Slag inclusions (ES May/June 2006)
- Intrinsic metallic inclusions (ES Sept/Oct 2006; CW 12/27/10, 12/27/11, 7/21/14)
- Lamination errors
  - Loss before strike
  - Loss after strike
  - Lamination cracks
  - Retained laminations
  - Folded-over before strike (CW 10/22/12)
  - Internally split clad layer (CW 10/22/12, 6/26/17)
- Split planchets
  - Before strike (CW 8/2/10)
  - After strike
  - Wrong Denomination / Off-metal
  - Struck with another planchet on top or beneath
  - Split core (clad coins)
  - Clamshell split (CW 1/28/13)
    - Clamshell folded over before strike (CW 10/22/12, 1/23/13)
  - Hemi-split planchets (CW 10/9/23)
- Copper-and-zinc composite “shells” (ES May/June 2001)
  - Split-after-strike (N.B. these are probably all detached cap bottoms)
- Cracked planchets
- Broken planchets / coins (CW 3/14/11, 9/18/23)
  - Before strike
  - After strike
- Brittle coins (cross-classified with annealing errors)
  - Radial planchet splits (when struck out-of-collar)
  - Delayed radial stress splits (CW 5/2/22)
- Planchet cohesion errors (crumbling planchets) (CW 11/22/21)
- Ragged clips (CW 2/29/16)
- Ragged notch
- Ragged perforations (“blowholes”)
- Fissures — ragged and smooth
- Stress-induced surface irregularities (CW 4/24/17)
- Rolling-Induced Fissures

Subsurface Corrosion (CW 12/21/15)

- Plated coins
  - Copper-plated zinc cents
- Solid coins

Rolling Mill Errors

- Rolled-thick planchets
- Rolled-thin planchets (CW 8/2/10, 7/16/18)
- Tapered planchets (CW 12/20/10, 12/28/15)
  - On clad coins (clad layer absent) (CW 4/27/15)
- Rolling indentations (ES Jan/Feb 2000; CW 2/7/11)
- Rolled-in scrap (ES May/June 2006; CW 2/7/11)
  - Bristles from descaling brush (CW 3/10/03)
- Roller marks (CW 10/13/14)
- Rolled-in patterns and textures
  - Rolled-in cloth pattern (CW 3/21/16)

Blanking and Cutting Errors

- Definition
- Curved (concave) clips (CW 6/29/15)
  - Crescent curved clips
  - Bowtie clips (ES Nov/Dec 2005; CW 6/16/14)
    - Two large clips at opposite poles – ends rounded
    - Four clips — punch slices through strip with normal hole spacing
    - Struck chopped webbing
- Straight clips (CW 1/14/13)
  - Smooth straight clips
  - Irregular straight clips
  - Sawtooth clips
  - Incomplete straight clips (actually struck-in cutting burrs)
- Straight cutting burrs (CW 1/14/13, 5/16/16)
- Corner clips (“outside corner clip”) (CW 1/14/13)
- Assay clips (“inside corner clip”) (cross-classified with pre-strike damage) (CW 1/21/13, 6/12/17)
- Ragged clips (also listed under alloy errors)
- Incomplete punch (incomplete clip) (ES May/June 2005; CW 3/24/14)
- Elliptical (convex) clips (ES May/June 2005; CW 4/5/10, 7/11/11)
- Multiple clips and combination clips (CW 1/27/14)
- Blanking burrs (“rolling fold”) (ES Jan/Feb 2007; CW 1/31/11, 5/29/17, 9/4/23)
  - COIN WORLD SPECIAL: article posted HERE
- Concave blanking burrs (CW 5/16/16)
- Punched-in scrap (ES May/June 2006)

Upset Mill Errors

- Coins struck on blank (“Type I planchet”)
- Abnormally weak upset (ES July/August 2005)
- Abnormally strong upset (best seen on off-center strikes)
- “Groovy edge” (possibly from worn groove in upset mill)
- Variation in cross-sectional shape of rim/edge junction of planchet
- Struck coin sent back through upset mill
- Abnormal upset (ES Sept/Oct 2005; CW 2/27/12, 11/21/16)
  - Wide, flat edge
  - Smoothly convex edge
  - Abnormally wide proto-rim
- Squeezed-in debris (upset mill inclusion) (ES May/June 2006; CW 9/6/10)
  - Foil-like metal wraps around edge onto one or both faces
    - e.g. Copper foil on nickels (not from improper annealing)
  - Metal wire wraps around edge onto one or both faces
  - Pellet embedded in edge (CW 9/6/10, 9/22/14)

Edge design errors (impressed into planchet before strike) (includes security edge errors) (CW 6/27/16)

- Edge design missing
- Edge design present on normally plain edge (CW 6/27/16)
- Wrong edge design
- Edge design too high or too low
- Interrupted edge design
- Tilted edge design
- Broken edging die (CW 6/27/16)

Mispunched center holes (foreign only) (CW 1/7/19)

- Misaligned holes
- Double punched center holes
  - One hole centered
  - Both holes misaligned
  - Overlapping holes
  - Totally separate holes
- Irregular center holes
- Abnormally small hole
- Partial hole (from broken hole punch)
- Circular Indentation (partial penetration)
  - Due to broken-off punch tip
- Unpunched center hole
- Hole punched in planchet meant for a solid coin

Annealing Errors

- Improper annealing (due to excessive heat, prolonged exposure to intense heat, or excessive oxygen in annealing oven) (replaces “sintered plating” and “copper wash”) (ES July/Aug 2010; CW 11/30/09, 2/8/10)
  - Black, brown, red, coppery discoloration (includes “black beauty” nickels)
  - Layer of copper, often peeling

Poorly annealed or unannealed planchets (hard, brittle planchets) (CW 3/14/11)

- Broken planchets and coins (CW 3/14/11, 9/18/23)
- Radial cracks in coin (usually struck out-of-collar)

Brittle coins (cross-classified with alloy errors) (CW 3/14/11)

Abnormally hard planchets (CW 12/17/12, 8/15/22)

- 1954-S nickels
- 1983-P nickels
  - COIN WORLD SPECIAL: article posted HERE
- “Superclash” 2000-P nickel (CW 3/22/10)

On undersized or underweight planchets (CW 2/13/12)

Miscellaneous forms of mint discoloration

Plating Errors

- Incomplete plating
- Unplated cents (CW 10/26/15, 7/24/23)
- Cents struck on unplated or partly-plated foreign planchets (CW 3/10/14)
- Thin plating
- Thick plating (ES March/April 2009)
- Blistered plating
  - Circular blisters
  - Linear blisters
  - Intact blisters
  - Ruptured blisters
- Brassy plating
- Split Plating (CW 12/18/17)
  - Split Plating Doubling
- Cracked and Peeling Plating (CW 12/18/17)

Bonding/Bonding Mill Errors (ES, Sept/Oct 2002)

- Missing clad layer
  - Full
    - Before strike (CW 5/23/22)
    - After strike
    - Before rolling is completed (weight may be close to normal) (ES Sept/Oct 2002, Nov/Dec 2006; CW 5/28/12)
  - Partial
    - Before strike
    - After strike
    - Before rolling is completed
  - Thin cladding
    - With gaps
  - Missing both clad layers (struck core)
    - Core thickness (ES Sept/Oct 2003; CW 3/18/13, 2/3/20)
    - Full thickness
- Struck Clad layer
  - Separated after strike
    - COIN WORLD SPECIAL: article posted HERE
  - Separated before strike
  - Struck by itself
  - Struck on top of or beneath a normal planchet
- Clamshell separation (CW 1/28/13)
  - Clad layer folded over before strike
- Missing core
  - Partial
  - Full (Coreless or all-clad coins) (CW 12/19/11)

Irregular planchets

- Scraps/fragments (CW 12/21/09, 1/27/20)
  - Normal alloy/composition
  - Off-metal
  - Feeder finger material
  - Foil
  - Heavier than normal coin of same denomination
  - Wider than normal coin of same denomination (along at least one axis)
- Ragged clip (cross-classified with alloy errors)
- Ragged notch (cross-classified with alloy errors)
- “Blowholes” (cross-classified with alloy errors)
- Fissures (cross-classified with alloy errors)
- Cracked planchets (cross-classified with alloy errors)

Pristine Planchets (i.e. lacking tumbling marks) (CW 1/11/16)

Pre-Strike Damage (CW 11/15/10, 11/15/10, 1/23/12, 1/30/12, 12/15/14, 4/13/15, 6/8/20)

- COIN WORLD SPECIALS: articles posted HERE and HERE
- Assay clips (cross-classified with blanking errors)
- Rim burrs (CW 1/31/11)
- Accidentally and intentionally “re-sized” planchets (CW 9/15/10)
- “Crimp marks” (mostly found on off-metal errors, e.g., 5c/1c, 5c/10c)
- Rockwell test mark in planchet (circular or oval dimple) (ES July/Aug 2006; CW 10/15/18)
- Planchet with adjustment marks (gold and silver planchets filed to return heavy planchets to normal weight)
- Edge rolled, squeezed, and folded-over (or with thin apron produced) (CW 11/15/10, 1/23/12, 6/15/20)
- Pre-plating damage (zinc cents) (CW 1/23/12)
- Post-plating damage (zinc cents) (CW 11/15/10)
- Scraped-in debris (CW 2/23/15)
- Repetitive pre-strike damage (CW 12/15/14)
- Other forms of pre-strike damage
  - Gouged (CW 1/14/19)
  - Crushed (CW 4/13/15)
  - Scraped (CW 2/23/15)
  - Torn
  - Crumpled (CW 8/15/11)

Inter-strike Damage (CW 1/9/12, 8/20/12)

- Cancelled or defaced between strikes (CW 3/25/13)

Trans-strike damage (CW 7/12/21)

Wrong planchet and off-metal errors

- Wrong planchet, correct composition
- Off-metal
  - Domestic planchet (CW 6/22/20)
    - Monroe dollar coin struck on a clad dime planchet
    - 1987-P Jefferson nickel struck on clad stock
  - Domestic struck on foreign planchet
    - 1941-P Lincoln cent struck on a Panama 1¼ bronze centesimos
    - 1920-P Lincoln cent struck on a Argentina 10 centavos planchet
    - 1905-P Barber dime struck on a Panama or Philippines five centavos planchet
    - 2000-P Sacagawea struck on a Ghana 100 Cedis ring
  - Foreign planchet
  - Unidentified origin and purpose (orphan) (ES Sept/Oct 2006, Nov/Dec 2006, March/April 2011, May/June 2011; CW 5/10/10, 12/19/11, 1/30/17, 11/30/20, 4/4/22)
  - Defective and damaged off-metal planchets (CW 3/21/16)
  - Foreign denomination struck on U.S. planchet
    - 1970 Philippines 25 Sentimos on a U. S. cent planchet (3.1 g)
    - 1972 Philippines 1 Peso on a U.S. clad 50 cent planchet
    - 2000 Canadian Pride 25 cent coin struck on a United States nickel planchet
  - Pure copper quarters and dimes (covered under bonding mill errors)
  - Pure clad dime (covered under bonding mill errors)
- Wrong stock errors
  - Correct composition
  - Off-metal (e.g, 1987-P nickel struck on clad quarter stock) (CW 4/22/13, 9/23/13, 9/10/18)
  - Transitional stock planchets (CW 9/23/13)
- Business strike on special off-metal planchet (CW 2/10/20)
  - (e.g., 40% silver-clad 1974-D and 1977-D Eisenhower dollars)
- Special strike on business planchet (CW 2/10/20)
  - (e.g., 1973-S Eisenhower dollar on Cu-Ni clad planchet)
- Business strikes on proof planchets (CW 11/14/11)
- Proof strike on business planchet
  - COIN WORLD SPECIAL: article posted HERE
- Wrong date error (covered under mules and die manufacturing errors)
- Double denomination errors (CW 10/3/22)
  - Same year
  - Different year
  - Over pre-existing wrong planchet/off-metal error (ES Sept/Oct 2017; CW 2/10/2014)
- Dual country (CW 3/21/11)
  - Same year
  - Different year
- Intentional overstrikes (not an error)
- Transitional planchet errors (“wrong series”) (ES Sept/Oct 2001; CW 3/28/16, 8/22/16)
  - Composition/year mismatch with non-overlapping production schedule
    - 1943 bronze cents (CW 4/11/16)
  - Composition/year mismatch with overlapping production schedule
    - 1965 silver dimes and quarters
    - 1964 clad dimes and quarters
  - Intra-year design/composition mismatch
    - 1991 Russia 10 kopek (ES Sept/Oct 2001)
  - Forward-jumping transitional planchet errors (CW 3/20/17)
  - Transitional/wrong denomination error
    - (e.g. 1965 quarter struck on silver dime planchet)
  - “Long pause” transitional planchet errors (CW 4/5/21)
- Struck on smaller planchet or coin
- Struck on same size planchet or coin
- Struck on re-sized planchet (dime design struck on cut-down cent planchet)
- Struck on larger planchet or coin (CW 8/22/22)
  - 1981 cent on nickel planchet, uniface reverse
  - 1981 dime on cent cap
  - 1981 cent design struck on Susan B. Anthony dollar (several known)
  - 2006 Chilean 10 pesos struck on a 100 pesos bi-metallic planchet
  - Canadian “assisted errors” 1977 – 1981
  - Malaysian “assisted errors” 2005-2007
- Struck on loose clad layer (covered under bonding mill errors)
- Weld seam planchets (controversial) (CW 9/24/12)
- Coins struck on washers, gears, and other hardware
- Coins struck on “aluminum” feeder fingers
- Experimental issues (CW 11/23/15, 5/23/16)
  - Experimental wartime planchets (CW 12/7/09, 12/21/09)
  - 1999 and 2000 state quarters on experimental planchets – tests for Sacagawea dollar (CW 11/26/01)
  - 1999 Susan B. Anthony dollars struck on experimental planchets (CW 8/5/02)
  - 1974 aluminum and bronze-clad steel cents (CW 1/13/03)

Bi-metallic errors (foreign only) (ES Nov/Dec 2005)

- Misaligned core (ES May/June 2007; CW 3/6/23)
- Misaligned center hole (ES Sept/Oct 2007)
  - Well-seated core (CW 3/6/23)
  - With misaligned core (CW 3/6/23)
- Double-punched center hole
- Unpunched center hole
  - Solid disc of ring metal (CW 3/26/18)
  - Solid disc of ring metal with embedded core
  - Solid disc of ring metal with core indent
- Ring with incomplete punch (ES Sep/Oct 2007)
- Core with incomplete punch
- Struck outer ring (ES Jan/Feb 2007)
- Struck core (ES Nov/Dec 2006)
  - From another denomination
  - From another country (ES Sep/Oct 2009, Nov/Dec 2011)
  - Struck by solid-denomination dies
- Wrong core inserted (ES Sep/Oct 2013; CW 10/17/22)
  - Core-sized scrap disc of ring material inserted into disc
- Wrong ring (ES March/April 2007; CW 10/10/22)
- Ring accidentally punched from solid planchet
- Ring accidentally punched from solid coin (ES Nov/Dec 2008)
- Struck ring from another country (restruck)
- Struck core from another country (restruck)
- Unstruck core inserted into struck ring and then restruck
- Abnormally small core (controversial)
- Abnormally wide center hole (controversial)
- Abnormally thin core
- Abnormally thick core
- Abnormally thin ring
- Abnormally thick ring
- Incomplete trilaminar core
  - Missing one layer (ES Mar/Apr 2010)
  - Missing two layers
- Core punched out of ring strip
- Ring punched out of core strip
- Bi-metallic planchet struck by solid-denomination dies
- Solid-denomination planchet struck by bi-metallic dies (ES Mar/Apr 2014)
- Bi-metallic planchet struck by wrong bi-metallic design

Green lettering – major heading

Blue lettering – linked to subject matter

Brown lettering – subject matter covered under that heading

Black lettering – no entry yet

Part VI. Striking Errors:

Unstruck blank (“Type I”)

Unstruck planchet (“Type II”)

Die alignment errors

- Rotated die errors (CW 6/21/10, 7/9/12)
  - Rotated die due to improper installation (fixed rotation)
  - Rotated die due to improper die preparation (fixed rotation)
    - (e.g., grinding flats in wrong spot)
  - Rotated die due to movement after installation (dynamic rotation)
  - Semi-stable rotated die errors (various causes)
    - Characterized by a limited range of motion, a limited number of positions, or the presence of a single dominant position (CW 7/9/12, 8/7/23)
- Pivoted die errors (probably involves entire die assembly) (CW 6/22/15)
- Horizontal misalignment (CW 10/27/03, 7/25/16)
  - Hammer die (CW 2/1/10, 6/25/12)
  - Anvil die (ES Sept/Oct 2004, March/April 2005; CW 9/27/10, 1/19/15, 1/4/21, 7/19/21)
    - With misaligned collar
    - With broken collar
  - Dynamic misalignment (CW 6/25/12)
  - Multiple misaligned strikes (CW 10/11/21, 11/29/21)
  - Stable misalignment
  - On double-struck coins
    - On first strike only (CW 8/31/20)
    - On second strike only (CW 5/19/08, 5/23/11, 9/9/13)
    - On both strikes
    - Alignment with off-center strikes (CW 8/19/19, 8/26/19)
- Vertical misalignment (tilted die error) (ES Jan/Feb 2003, Sept/Oct 2003; CW 12/8/03, 12/20/10, 8/24/15, 10/24/16, 1/8/24)
  - Hammer die (CW 2/1/10, 6/17/13)
  - Anvil die
  - Dynamic misalignment (CW 10/24/16)
  - Stable misalignment (CW 1/29/14)
  - Associated with weak strike (? 2/1/10, 10/8/12, 8/16/21)
  - Associated with off-center strike (? 8/13/18)
- Dual misalignments (both dies misaligned in different directions) (CW 11/28/11, 5/18/15, 1/9/17, 7/9/18)
- Compound misalignments (CW 8/24/15)
  - Horizontal and vertical
  - Horizontal and rotated
  - Rotated and vertical
- Forced misalignments (CW 8/28/17)

Collar alignment errors

- Misaligned collar
  - Associated with misaligned anvil die
  - Associated with stiff collar error
  - Associated with elliptical strike clip
- Rotating collar (detectable only when there’s a collar break and a multi-coin progression)

Collar deployment errors

- Partial collar (CW 2/24/20)
  - Flange with bevel
  - Flange without bevel
  - Tilted partial collar
  - Undulating partial collar (CW 2/24/20, 7/25/22)
  - Re-entry partial collar
  - Incomplete ejection partial collar (CW 12/26/22)
  - Reversed partial collar (not an error)
  - Multiple steps (CW 3/15/21)
- High deployment of collar with coin metal extruded beneath (doubtful)
- Broadstrikes
  - Centered
  - Uncentered (CW 7/20/15)
  - Cupped broadstrike
  - Forced broadstrike (CW 1/10/11, 11/30/15)
  - Partial collar broadstrike (shows incomplete, tilted partial collar)
- Stiff collar errors (ES Nov/Dec 2000; CW 8/25/08)
  - Normal die installation
  - Inverted die installation
  - Association with misaligned dies
  - Association with misaligned collar
  - Strong collar scar
  - Strong collar scar with cupping
  - Planchet forced completely into fully deployed collar (“ram strike”) (ES Nov/Dec 2000, March/April 2001)
  - Elliptical strike clip (ES March/Apr 2000; CW 4/5/10)
  - Associated with weak strike (CW 2/11/13)
- Collar shimmy (CW 8/21/17, 9/11/17)

Weak Strikes (ES Sept/Oct 2000; CW 5/3/04, 9/11/06, 6/18/07, 3/1/10, 5/23/11, 6/23/14, 8/27/18, 3/2/20, 10/26/20, 11/27/23)

- Caused by insufficient die approximation
- Caused by abnormally low ram pressure
- Invisible strikes (ES March/April 2003, Nov/Dec 2003, March/April 2004, Nov/Dec 2006, May/June 2010; CW 5/3/10, 9/20/10)
  - With indent
  - With partial brockage
  - With struck-through error
- Followed/preceded by strong strike (CW 7/13/20)
- Stable series of weak strikes (CW 8/27/18)
- Weak saddle strike
  - One strike weak, one strong (CW 4/8/13)
  - Both strikes weak (CW 12/12/11)
- In combination with other striking errors
- Rim-restricted first strike (CW 3/1/10, 10/10/11, 1/11/16, 2/19/18, 9/23/19)
- Rim-restricted second strike (CW 9/21/15, 2/13/17)

Skidding Coin Errors (CW 1/29/18)

Abnormally Strong Strikes

- Due to elevated ram pressure
  - Finning (CW 8/23/04, 7/6/20)
  - Encircling pressure bumps (CW 12/2/23)
- Due to elevated ram pressure or reduced minimum die clearance
  - Extremely large broadstrike (CW 7/26/10)
  - Extreme stretch strikes with both sides die-struck
- Due to stacked coins or planchets (CW 12/7/20)
- Localized, due to die tilt

Stutter Strikes (ES Nov/Dec 2001, Sept/Oct 2007; CW 12/28/09, 7/25/11, 8/10/20)

- Due to spasmodically collapsing or stiff collar (Type I)
- Due to planchet flexion (associated with indents and brockages) (Type II)
- Due to contact with bent planchet or coin (Type III)
  - On face struck by anvil die (CW 8/26/13)

Concentric strike lines generated by a single strike (ES Jan/Feb 2012; CW 12/26/11)

Machine doubling (a.k.a. machine doubling, machine doubling damage, machine damage doubling, mechanical doubling, strike doubling, shift doubling, ejection doubling) (ES July/Aug 2006; CW 3/15/10, 7/24/17, 12/23/19, 3/30/20)

- “Push doubling” (marginal shelving and sharp interior duplication) (CW 1/9/23)
- “Slide doubling” (smeared design) (CW 8/14/17)
- Rotational machine doubling (CW 8/10/15)
- Intermediate forms
- Multiple machine doubling in one direction (two, three, and four offset ranks)
- Machine doubling in more than one direction (up to three directions)
- Machine doubling on both faces of same coin (CW 3/15/10, 12/23/19)
- Rim-restricted design duplication (see separate category)
- Affecting incuse design elements (CW 2/6/06, 1/16/12)
- Located on top of die break
- Located on top of die attrition error (CW 4/14/14)
- On out-of-collar strikes (rare) (CW 11/25/19, 11/21/22)

Rim-restricted design duplication (form of machine doubling) (CW 10/6/03, 2/22/10, 5/24/10, 12/6/10, 5/13/13, 12/30/13, 3/8/21, 4/12/21)

- 2004 cent (ES March/April 2007; CW 2/22/10)
- 1994 cents (CW 5/24/10, 8/22/11)
- 1981-P quarter and 1979-D dime (CW 12/30/13)
- Presidential dollars (ES Sept/Oct 2007; CW 2/22/10, 12/6/10)
- Foreign coins (CW 2/22/10)
- On face struck by anvil die (CW 10/21/13, 7/20/20)
- Bifacial (7/20/20)
- In conjunction with push doubling (CW 12/6/10, 7/20/20)

Ejection Doubling (CW 11/7/22)

Skidding Die Errors (CW 8/15/16, 11/27/17)

- Skidding misalignment
  - Two-stage (CW 4/13/20)
- Design decapitation error (top of design scraped off)
- Slide doubling (see Machine Doubling)
- Design ablation error (design scraped off by die movement on 2^nd strike) (ES March/April 2008, Jan/Feb 2011; CW 9/13/10)
- Combined with tilted die (CW 9/27/21)
- From broken die (CW 7/26/21)

One-sided double-strikes (ES March/April 2000, Jan/Feb 2002, July/August 2003)

- Hammer die rotated (CW 11/29/10)
  - Instantaneous
  - Gradual
- Hammer die misaligned (CW 5/19/08, 5/23/11, 9/9/13, 3/8/21, 4/24/23)
  - Instantaneous
  - Gradual
- Anvil die misaligned (CW 9/9/13)
- Anvil die rotated (at least one known example, a proof Kennedy half dollar)
- Rotated, with rocking die (CW 5/25/20)
- False one-sided double strikes (CW 11/29/10)

Flat Field Doubling (imperfectly aligned proof strikes) (CW 4/29/13)

Off-center strikes

- Cupped off-center strikes
  - With collar scar
  - Without collar scar
- Uniface strikes
- Stretch strikes
  - Uniface
  - Die struck on both faces (covered under high pressure strikes)
  - With unexplained, flat dent at opposite pole (not a “sideneck strike”)

Chain strikes (CW 4/12/10)

- Normal chain strikes with straight edge
- External chain strikes (ES Jan/Feb 2003)
- Concave, convex, sinuous, and irregular chain strikes (ES Jan/Feb 2001, July/August 2002; CW 4/12/10)

Foreign Object Chain Strike (CW 5/25/15)

- Chain strike against feeder

Machine Part Impingement (CW 5/25/15)

- Bilateral
- Unilateral

Saddle (Tandem) Strikes (CW 6/27/11)

- Hump present
- Hump absent
- Inverted hump (hump points toward reverse die) (CW 9/19/16)
  - Buckling toward anvil die
  - Due to inverted die setup
- Die position
  - Head-to-head
  - Head-to-base (early to mid- ’70s, mainly)
  - Face-to-back
- Gap between adjacent dies
  - Narrow
  - Wide
- With inverted die installation
- Sideneck strikes (“one-die saddles”) (Expanding planchet collides with side of die neck) (CW 5/30/11)
- On quarter dollars (CW 12/9/19)

Broadstrikes

(covered under collar deployment errors)

Split Plating Doubling

Foldover Strikes (ES July/August 2007; CW 10/10/05, 8/15/11, 1/30/12, 9/15/14)

- Out-of-collar
- In-collar
- With edge strike persisting
- On struck cents (normal and error)
- Double foldover strikes (“Z-fold”)
- Axial fold
- Paraxial fold
- Inward fold
- Outward fold

Edge Strikes (CW 7/18/11, 10/12/15, 3/1/21)

Extrusion strikes (an effect, not an independent error) (ES March/April 2004; CW 10/24/11, 1/15/18)

- With indent or partial brockage
- Between two indents or partial brockages
- With struck-through error
  - Struck through clipped planchet
- With retained cud

Multiple strikes (CW 3/30/15)

- On-center/Off-center
- In-collar/out-of-collar
- Flipover
- Numerous closely-spaced strikes (ES Nov/Dec 2004; CW 1/11/21)
- Involving second die pair
- Delayed second strike (ES July/August 2007; CW 1/9/12, 6/13/16, 6/6/22, 1/23/23)
- Dual-date double strike (CW 6/13/16)
- Proof double strikes (CW 9/19/22)

Indents

- In-collar/out-of-collar
- Partial
- Full (CW 7/30/12)
  - Centered
  - Uncentered
- “Internal” indents (CW 11/1/10, 2/28/16)
  - On obverse
  - On reverse
- Multiple indents
- Irregular indents
  - Produced by error coins
  - Produced by clipped planchet
- Indent by smaller planchet (CW 5/19/08)
- External disc impressions (CW 3/18/19)
- Unexpectedly shallow indents (CW 12/28/20)

Brockages

- Full
  - Centered
  - Uncentered
  - Rotated (relative to die-struck design on opposite face)
- Partial
  - Conventional
  - Aligned partial brockage (ES May/June 2005; CW 1/17/11, 12/5/22)
    - From partial die cap
    - From elliptical clip coin
    - From elliptical strike clip
  - Internal partial brockage (CW 11/1/10)
- In-collar/out-of-collar
- From another denomination (ES May/June 2005; CW 8/1/21)
- From another error coin
  - From wrong planchet error (CW 11/28/22, 6/12/23)
  - From mangled and crumpled coins (often multi-struck) (CW 10/2/23)
  - From weakly-struck coins (CW 11/20/23)
- Flipover brockage (CW 4/23/12)
  - On obverse
  - On reverse
- First-strike brockage
  - “Mirror” brockage (unexpanded, undistorted) (CW 6/13/11, 3/17/14, 5/6/19, 10/28/19, 7/11/22, 6/27/22, 4/10/23)
  - Distorted first-strike brockages
- Mid-stage and late-stage brockages
- By struck fragment (CW 6/11/12)
  - Aligned with opposite, die-struck design
  - Not aligned with opposite design
- From struck die fill (very rare) (CW 8/20/18)
- From thin pieces of metal (CW 7/23/18)
- From large dropped filling (CW 5/13/19)
- Multiple brockages CW 9/26/11)
  - From multiple strikes
  - From clashed cap
  - From multi-struck coin (CW 7/4/22)
  - From more than one coin in striking chamber
  - From coin trapped between die cap and planchet
- Clashed cap strikes (CW 8/30/10, 11/21/11, 1/13/14)
  - From a late-stage die cap that clashed with the opposite die
  - From a uniface die cap that clashed with the opposite die
  - From an early-stage die cap that clashed with the opposite die
  - From a cap that was striking counterbrockages that clashed with the opposite die
  - From a flipover die cap that clashed with the opposite die (CW 1/13/14)

Counterbrockages

- Full (CW 10/11/10)
- Partial (CW 11/8/10)
- In-collar/out-of-collar
- Counterbrockage of obverse on obverse
- Counterbrockage of reverse on reverse
- Flipover counterbrockage (CW 4/19/21)
- Early, middle, and late-stage counterbrockages
- From another error coin
- Brockage-counterbrockage combination (8 types) (ES Nov/Dec 2009; CW 11/12/12)
- Multiple counterbrockages (ES March/April 2010)
- On second strike
- Rebound counterbrockage (always on 3^rd strike) (CW 11/9/15)
- Secondary counterbrockage (CW 4/19/21)
- Grease-generated counterbrockage (CW 4/11/22)

Horizontal lipping (CW 11/30/15)

- In conjunction with in-collar indents, partial brockages, and struck-through errors

Die caps (CW 8/6/13, 1/7/20)

- Hammer die caps (usually the obverse die)
  - Raised design on working face
  - Brockage on working face
  - Uniface die caps
  - Complex die caps
- Anvil die caps (usually the reverse die)
  - Cupped toward anvil die, hammer die, both dies at opposite poles, or expanded in the horizontal plane
- Partial (off-center) die caps (hammer or anvil) (CW 1/17/11)
  - With cupping
  - Without cupping
- Detached cap bottoms (ES March/April 2001, May/June 2001)
- Clashed caps (CW 1/22/24)

Capped die strikes (generic — without identifiable images)

- Struck by uniface die cap
- Struck through late-stage die cap
- Struck through cap-like obstruction
- Struck through split or torn cap
- Proportional de-expansion (both faces struck through die cap or cap-like obstruction) (CW 11/11/13, 5/28/18)

Struck by impaled die cap (CW 6/10/13)

Capped die doubling (doubling associated with capped die strikes) (ES Sept/Oct 2005; CW 6/18/12, 5/16/22)

- Shifted/rotated cap strikes (ES May/June 2000, March/April 2012; CW 11/21/11)
  - Correctly-facing incuse design elements (CW 11/3/08, 6/28/10, 6/11/12, 10/19/15, 8/12/19, 10/23/23, 11/13/23)
    - Multiple sets due to several preceding shift-and strike event
- Unexplained, close raised doubling
  - Expansion ripples
- Incuse doubling surrounding raised elements (CW 8/24/20)

“Struck-through” errors

- Struck through fragment
- Struck through clipped planchet (ES Sept/Oct 2002; CW 8/25/14)
- Struck through thin struck fragment (CW 6/11/12)
  - Face-up (normally-oriented incuse design elements)
  - Face-down (mirror-image design elements)
  - Trapped between planchet and opposite die (mirror-image design elements)
- Struck through detached lamination flake (CW 2/7/05, 6/11/12)
- Struck through clad layer
  - Clad layer unstruck
  - Clad layer previously struck
- Struck through reeding (CW 11/14/16, 8/21/23)
- Struck through split planchet
  - Obverse
  - Reverse
- Struck through hardware (bolts, screws, washers, etc) (CW 3/7/11)
- Struck through feeder (ES Nov/Dec 2005; CW 3/7/11)
- Struck-through unidentified machine part (CW 3/7/11)
- Struck through emery disc (CW 12/16/02)
  - 1986 Silver Eagles struck through emery disc (CW 12/16/02)
- Struck through “grease” (die fill)
  - Assorted ingredients, textures, viscosities, and consistencies (smooth, coarse, stiff, viscous, etc.)
  - “Greasy ghosts” (ghost images from grease accumulations) (CW 7/5/10, 7/10/17)
  - Grease-mold doubling (ES March/April 2006, July/August 2006, Nov/Dec 2008; CW 8/19/13, 10/20/14)
  - Grease-mediated radial smear (CW 7/31/17)
  - “Spackled dies” (intentionally applied grease) (CW 10/18/21)
  - Bifacial (5/22/23)
- Filled dies
  - Single design element (CW 6/29/20)
  - Multiple design elements
- Struck through bulging die filling (CW 1/16/17, 5/20/19)
- Filled collar/obstructed collar (ES Jan/Feb 2006; CW 9/22/14)
  - With flange
- Surface Film Effects (ES May/June 2003; CW 8/16/10, 6/11/12, 10/29/12)
  - Surface film doubling
  - Surface film afterimage
  - Surface film transfer
  - Surface film transfer with clash marks
- Dropped fillings (ES May/June 2003; CW 8/16/10, 6/11/12, 10/29/12)
  - Isolated elements (dropped letter, dropped number) (CW 2/7/05)
  - Conjoined dropped fillings (CW 8/16/10)
  - Large, multi-element dropped fillings (CW 4/19/10, 8/16/10, 11/14/22)
  - Retained dropped fillings
- Struck through floating encrustation (on second strike) (CW 1/18/16, 6/18/18)
- Yanked-out fillings (CW 1/16/23)
- Struck through miscellaneous foreign matter
  - Metal dust, shavings
  - Cloth (CW 5/14/12, 12/3/18, 9/26/22)
  - String (CW 3/9/20)
  - Wire
- Field-restricted struck-through errors (CW 11/18/13)
- Split or torn in two by struck-thru object (ES Nov/Dec 2007; CW 3/7/11, 7/13/15)
- Retained struck-through errors (struck-in errors) (CW 7/18/16, 1/25/21, 9/13/21)
  - Embedded dropped filling (see above)
  - Embedded die fill (shapeless)
  - Die fragment (CW 2/6/23, 3/13/23)
  - Scrap metal
  - “Staple” (bristle from wire brush)
  - Plastic (associated with bullion coins)
  - Metal foil
    - (Cu-Ni)? associated with dimes and nickels)
    - Copper foil (ES Nov/Dec 2007)
  - Rubbery material (from die cover?)

Uniface strikes (cross-classified with indents) (CW 7/30/12, 9/16/19)

- In-collar (CW 12/5/22)
- On second strike (CW 11/29/10, 9/16/19, 6/5/23)
- “Augmented” in-collar uniface strikes (CW 9/14/20)
  - Out-of-collar
    - Centered
    - Off-center

Sandwich strike (coin struck between two coins or planchets) (CW 5/16/11, 10/31/16, 11/20/17, 5/28/18, 3/22/21)

- Partial
- Full
- Between two struck coins
- Between two planchets
- Between a coin and a planchet
- Between struck coin and obverse die cap
- Between obverse and reverse die cap

Nested coins (CW 3/16/20)

Mated pairs (CW 11/9/20)

Bonded coins

- pile-ups (clusters)

Strike clips (ES July/Aug 1999, May/June 2001; CW 6/15/15)

- Vertical shear clips (V)
  - Sheared between die and collar alone
  - Sheared between collar and overlying planchet
- Horizontal shear clips (H)
- Tensile strike clips (T)
- Concave strike clips (V, H, T)
- Elliptical strike clips (V, H ,T) (CW 4/5/10, 12/5/22)
- Straight strike clips (H)
- Saddle strike/strike clips (H)

Detached reeding

- From forced broadstrikes
- From stiff collar
- Torn-off fin

Coin shrapnel (“breakaway fragments”)

- Angular
- Crescentic
- Oval
- Circular or sub-circular
- Semilunar
- Irregular

Intra-Strike Damage (damage coincident with strike) (CW 5/30/11, 12/20/21)

- - Flat contact facet at 6:00 opposite off-center strike
  - Machine part impingement on unstruck portion of off-center coin (CW 5/25/15)
  - Ejection damage to edge of unstruck perimeter.
  - External struck-through errors (with cupping) (CW 3/25/19)
  - Concave damage opposite off-center strike (12/30/19)

Cupping (CW 12/7/09)

- With and without collar scar
- In a single strike
- Associated with multiple strikes
- With die caps
- Cupping toward hammer die
- Cupping toward anvil die
- Expansion in horizontal plane
- On unobstructed strikes (CW 3/18/19)
  - Spontaneous
  - Forced
    - By stiff collar
    - By outlying disc of coin metal
    - By foreign metal or machine part

Impact-Induced Warping (CW 3/16/15, 1/13/20)

Malrotation Errors (multi-sides coins only) (CW 3/23/15, 11/8/21)

Proof edge lettering errors (generated during strike by segmental collar)

- Weak edge design due to segmented collar not closing fully (wide seams)
- Segments arranged in incorrect sequence (see Die Installation Errors) (CW 4/7/08)

Green lettering – major heading

Blue lettering – linked to subject matter

Brown lettering – subject matter covered under that heading

Black lettering – no entry yet

Improper Alloy Mix

PART V. Planchet Errors:

Improper Alloy Mix

Definition: The term “improper alloy mix” can apply to two related errors. The constituent metals of a solid-alloy coin can be well-mixed but in the wrong proportions. In the case of a copper-alloy cent with too much tin or zinc, this will result in a brassy color. Alternatively, the constituent metals can be in the right proportions but poorly mixed. This will leave the coin with light and dark bands. Of course, the two mistakes can occur together.

The most extreme improper alloy mix errors are those in which the minor metallic element isn’t mixed in at all. This would be a type of “intrinsic metallic inclusion”.

This 1941 cent has a brassy color and consists of 86% copper, 11% zinc, and 3% tin. A normal copper-alloy cent
of this period is 95% copper, with the remaining 5% tin and zinc. The component metals are relatively well-mixed. This coin is also significantly overweight at 3.40 grams. So it combines an improper alloy mix error with a rolled-thick error.

Light and dark bands on this 1941 cent indicate poorly-mixed constituent metals. The lighter bands are enriched in zinc, tin, or both.

An unmixed globule of tin or zinc is responsible for the gray band that crosses the obverse face of this 1948 cent. This is an intrinsic metallic inclusion.

The 1938 (P) Lincoln cent shown above has a poorly blended mixture of copper, tin, and zinc. This has resulted in mottled bands of discoloration on both the obverse and reverse of the coin.

A poorly mixed alloy can result in alternating light and dark streaks. This is often referred to as a “wood grain” pattern, and the coins themselves as “woodies”.

The 1908 British half penny shown above has lamination errors and a poorly mixed alloy. The lighter-colored material seen on both the obverse and reverse of the coin is presumably enriched in tin. This poor alloy mix may have contributed to the lamination peels.

Index Of Completed Entries

Index entries are a mixture of higher-level and lower-level entries. Lower-level entries are often inserted into the index in alphabetical order and may therefore be separated from the higher-level entry they fall under in the Checklist.