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Part V. Planchet Errors:


Alloy errors

Subsurface Corrosion (CW 12/21/15)

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

Rolling Mill Errors

Blanking and Cutting Errors

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)

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

Miscellaneous forms of mint discoloration

Plating Errors

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

Irregular planchets

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

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