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Cutting Burr

Part V. Planchet Errors:

Blanking and Cutting Errors:

Cutting Burr

Definition: A burr that is generated when the ends or sides of the strip are trimmed or when the strip is split longitudinally.  When a shearing blade, saw, or guillotine trims the strip, this may generate a burr along the trimmed edge.  If this burr curls over onto the surface of the strip and this area is subsequently sliced through by a blanking punch, the result is a straight clip blank with a burr that will eventually be struck into the coin.  The coin will show a straight clip that is paralleled by a narrow fissure.  The fissure marks the internal edge of the struck-in cutting burr.  Almost all cutting burrs are restricted to one face.

The fissure that marks the edge of a struck-in cutting burr used to be erroneously identified as an “incomplete straight clip”.  It was also once thought that the fissure was a scar produced by a guide or stop next to the cutting edge.

01_str_clp_198xD_1c

Struck sometime between 1980 and 1982, this copper-alloy Lincoln cent shows a straight clip and, next to it, a struck-in cutting burr.  The fissure demarcating the internal edge of the burr is easily seen.

cutting_burr_2008P_OK_25c_obvcutting_burr_2008P_OK_25c_rev

Images courtesy of Jon Sullivan

This 2008-P Oklahoma quarter is the only known example of a straight clip with cutting burrs on both faces.  Metal derived from the copper core curled onto both faces and was eventually struck into both faces.  Fissures marking the internal edge of the cutting burrs are easily seen.

 

Die Rings (Tiny Rings, Semicircles, Crescents, And Spirals)

Part IV. Die Errors:

Die Damage:

Die rings (tiny rings, semicircles, crescents, and spirals)


Definition: Tiny rings, semicircles, crescents, and spirals that usually appear in the center of the coin or nearby. Their origin is a mystery and it’s likely that they have more than one cause.

Many rings are isolated, while others form concentric arrays. Size is somewhat variable, ranging from a fraction of a millimeter to almost 2 millimeters. Die rings can be smooth or have a rough appearance. They occur on all denominations from cent to quarter dollar. They can appear on either face, irrespective of whether that face was struck by the hammer or the anvil die.

Two offset crescents or semicircles overlap tip-to-tip to form a composite ring that encircles Lincoln’s statue on the reverse face. A number of reverse 2004 cent dies show similar rings or partial rings on the reverse face.

A single complete ring overlies Lincoln’s neck and jawline on this 1988 cent. Photo courtesy of Jason Cuvelier.

A concentric pair of relatively large, centrally-located, “spiky” die rings appears on the obverse face of this 2018 Lincoln cent.

This clearly defined, tiny die ring is surrounded by additional faint, closely-spaced concentric rings. This is one of many recent reverse nickel dies with rings in Monticello’s doorway. Many rings occur in isolation and most are identical in size to this one. Positions vary slightly but it seems all of them are slightly to the left of center. Dates range from 2012-P to 2015-P.
[2014-P in photo]

This 2012-P nickel features a relatively large, incomplete ring on the reverse face. Its large size, irregular margins, and coarse texture suggest it has a different origin from the small rings.

A centrally-located raised spiral appears on the obverse face of this 2010 cent. Photo courtesy of Richard Cooper.

Struck Through Floating Encrustation

Part IV. Striking Errors:

Struck-Through Errors:

Struck Through Floating Encrustation

Definition: A floating encrustation is a piece of compacted die fill or caked-on grime that enters the striking chamber and is struck into a coin.  Stiff, caked-on grime can come from the bowels of the press.  The lubricated joints and rods are a magnet for dust and dirt.  This material can stiffen over time and then break off.  Die fill (“grease”) is a compacted layer composed of lubricant, dirt, and metal dust that accumulates on the die face.  Pieces can break away to form nondescript struck-through errors.  In either case, the resulting struck-through error resembles a conventional “grease strike”.

The impression left behind by a floating encrustation can be expected to show:

  1. Soft or indistinct margins
  2. Variable depth (reflecting variable thickness of the foreign material)
  3. Variable topography (potentially smooth to rough)
  4. Occasional gaps or thin areas that allow the design to emerge.

There are only two practical ways to distinguish a floating encrustation impression from a grease strike:

  1. Assemble a progression (defined by die markers) that shows the sudden appearance of a struck-through area.
  2. Find a double-struck coin in which the first strike is unobstructed and the second strike is partly or fully obstructed.

floating_encrustation_Argentina_10c_obvfloating_encrustation_Argentina_10c_rev

This broadstruck 1994 Argentina 10 centavos shows an unobstructed first strike.  The second strike was almost fully obstructed on the reverse face by what seems to have been a floating encrustation.  The reverse face was struck by the hammer die.  First-strike elements are flattened, but retain sharp margins.  The only second-strike element to emerge is the C of CENTAVOS.  The irregular texture and indistinct margins of the struck-through area are consistent with a floating encrustation.

floating_encrustation_India_2003_1rupee_obvfloating_encrustation_India_2003_1rupee_rev

This double-struck 2003 India 1 rupee coin shows an unobstructed first strike.  The second strike was fully obstructed on the reverse face, which was struck by the anvil die.  The minimal flattening of the first-strike elements and the variable depth and topography of the impression are inconsistent with a uniface strike against another steel 1 rupee planchet.  I suspect a dollop of stiff grime entered the striking chamber and somehow found itself between the anvil die and the off-center coin on top.  The subsequent strike flattened the crud deposit into a disc-like shape.

 

Pristine Planchets

Part V. Planchet Errors:

Pristine Planchets

Definition: A planchet that lacks the usual tumbling marks and instead has a surface free of imperfections.  Faint roller marks are often present.

A blank (and later on, a planchet) goes through a rough-and-tumble existence as it travels toward the striking chamber.  It picks up small nicks and dings (tumbling marks) as it jostles against equipment and other planchets.  Tumbling marks are picked up as planchets travel along conveyors and are dropped into hoppers and tote bins.  Tumbling marks are even more likely to be inflicted as planchets bounce around in the rotating annealing oven.  Additional hazards await within the rotating, perforated cylinders that spin blanks and planchets through a quench tank, a chemical rinse bath, and a dryer.

Tumbling marks are eventually erased during a normal strike.  But they will persist in the case of off-center strikes and weak strikes.

Off-center strikes and weak strikes that lack tumbling marks present a conundrum.  There are several possibilities (not necessarily mutually exclusive):

  1. The planchet was just lucky.
  2. The planchet skipped the annealing oven.  The annealing oven appears to be the apparatus most likely to bang up a planchet.  Also, a non-annealed planchet is work-hardened, and resists damage.
  3. The planchet was abnormally hard as the result of a problem with the alloy.
  4. The planchet was prepared for a special purpose.

pristine_plan_1986P_5c_obvpristine_plan_1986P_5c_rev

The design of this 1986-P nickel did not strike up completely.  The incomplete strike appears to be the result of an abnormally hard planchet rather than a weak strike.  Unstruck areas are devoid of tumbling marks and instead show fine roller marks.  I suspect this planchet bypassed the annealing oven.

pristine_plan_oc_weak_stk_10c_obvpristine_plan_oc_weak_stk_10c_obv_obliqueObverse

pristine_plan_oc_weak_stk_10c_rev                                                                                     Reverse

This dime received and exceedingly weak, 70% off-center strike.  Design elements are almost completely restricted to the planchet’s proto-rim.  Obverse elements consist of Roosevelt’s lower lip, chin, throat, and the back of his neck.  Reverse elements consist of part of the torch’s flame, and two olive leaves.  The planchet is devoid of tumbling marks and instead has a bright, smooth surface covered by fine roller marks.

 

This may be a specially prepared planchet, although it’s not a proof.  The planchet shows an unusual pattern of upset.  The proto-rim is unusually sharp and narrow, while the edge is gently convex instead of trapezoidal in vertical cross section.

 

Subsurface Corrosion

Part V. Planchet Errors:

Subsurface Corrosion

Definition: Corrosion that occurs beneath the surface due to the presence of contaminants that react with the surrounding metal.  Subsurface corrosion produces an expanding lens of spongy rot that forces up the overlying metal into various shapes.  These solid elevations can be round, oblong, or elongated.  If the roof ruptures, the exposed rot can fall out or collapse, leaving a crater.

Subsurface corrosion can occur in solid-metal coins, appearing most frequently in aluminum coins.

Subsurface corrosion occurs even more frequently in plated coins, when contaminants get trapped between the plating and the core.  For example, in copper-plated zinc cents, domes of solid rot will push up the overlying copper plating.  These domes can resemble plating blisters, but their etiology is entirely different.  Plating blisters are hollow and are produced by expanding gas in the immediate aftermath of the strike.

Although subsurface corrosion is technically a planchet error, it is undesirable and has no value.

SKorea_1won_corrosion_ridge_obvcorrosion_ridge_close

This solid-aluminum 1969 South Korea 1 won shows the effects of subsurface corrosion on its obverse face.  A long, thin ridge is the dominant feature.  Although it resembles a die crack, the fact that the design continues across it shows that this is not the case.  Accessory patches of corrosion are found elsewhere on the obverse.  Some of the smaller pimples have ruptured, exposing pale, milky rot.

FUN 2016 Winter Convention

Once again Florida United Numismatics will be in the great city of Tampa, Florida. This year’s FUN show will be conducted at the Tampa Convention Center from January 7th until January 10th, 2016. This is the same venue where we held the very successful 2011 Winter Fun Convention.

Our bellwether show will offer over 600 tables of the finest dealers, with a huge assortment of coins and currencies from both the United States and abroad. There will be educational exhibits that will astound one’s mind and there are sixteen extremely interesting numismatic presentations from some of the leading experts in this hobby being held from Thursday until Saturday.

As always, leading this show’s attraction is the world class auctions by Heritage, who seem to always have some very interesting, unusual and very rare coins and paper money up on the auction blocks.

It is again our honor to have the U. S. Mint and Bureau of Engraving and Printing at this show; they always have outstanding exhibits. Special guest Abraham Lincoln (Dennis Boggs) will be present as well as Piedmont Gold Panners who will have their full set-up for those willing to try their luck in getting that valued nugget of gold. They will show you the ins and outs of panning for gold and all that you find you can keep.

If you are looking to have that certain coin graded and encapsulated, the four top end Third Party Grading companies will be in attendance; ANACS, ICG, NGC and PCGS. If it is numismatic supplies that you need, Leaphart, Lighthouse, Whitman and Wizard will be at this show as well.

There will be special sections for “Ancient & Foreign Dealers” and be sure to visit the “Specialty Clubs” area for some great give-aways and information on joining these specialty clubs.

On Saturday the 9th of January, 2016, YN and Scout Merit Badge programs will be conducted at the show in a prearranged area.

Folks, this is one numismatic coin show that should be on everyone’s “bucket list”. So, bring the family and friends for there are extraordinary sights and events for all ages and genders at this wonderful extravaganza.

For more information, follow the below links:

YN and Scout Merit badge

FUN Convention Information

Tampa Convention Center Parking

Slide Zone Ghost Elements

Part X. Wastebasket/Composite Categories:

Ghost Images:

Slide Zone Ghost Elements

Description: Outlines and silhouettes of peripheral letters (and occasionally the last digit of the date) located in the slide zone of off-center zinc cents.  The ghost elements consist of exposed zinc surrounded by intact copper plating.  Plating of just the right thickness, combined with just the right striking pressure, produces slight disruption of the copper plating.  The ghost elements record the point of initial contact between the dies and the planchet.

Slide_zone_ghost_letters_obvSlide_zone_ghost_letters_rev

The reverse face of this off-center copper-plated zinc cent shows ghost letters in the slide zone.  The letters of UNITED STATES take the form of outlines and silhouettes of exposed zinc.  There are no slide zone ghost elements on the obverse face.

 

Rebound Counterbrockages

PART VI: Striking Errors

Counterbrockages:

Rebound Counterbrockage

Definition:  A counterbrockage produced during a third strike that closely overlaps flattened first-strike design elements.  The sequence of events begins when a struck coin and an unstruck planchet are both present in the striking chamber.  After a normal first strike, the coin is struck a second time with a planchet partly or completely covering one face.  This leaves an indent on the first coin whose floor is adorned by flattened first-strike design elements.  The intrusive planchet is converted into a broadstrike or off-center coin that has a first-strike brockage on one face.  After the second strike, the intrusive brockaged coin shifts position relative to the indented, double-struck coin.  The brockaged coin is driven back into the indent, with the brockaged elements acting as a “soft die”.  The brockaged elements generate a counterbrockage that overlaps the flattened first-strike elements.

Pakistan_1rupee_rebound_cbrkge_2005_obv Pakistan_1rupee_rebound_cbrkge_2005_rev rebound_cbr_Pakistan_1rupee_2005_date

This 2005 Pakistan 1 rupee coin received a normal first strike.  It was then struck a second time in a slightly off-center position while partly covered by an intrusive planchet.  This produced an indent in the bottom coin within which lay flattened first-strike elements that include Mohammed Jinnah’s neck and the date.  The overlapping planchet was converted into an off-center coin with a first-strike brockage of the obverse design on its reverse face.  After the second strike, both the double-struck coin and the brockaged off-center coin shifted toward the north, with the off-center coin lagging behind slightly.  The brockaged face of the off-center coin was driven back into the indent, producing a set of raised, counterbrockage elements that overlap the flattened first-strike elements.  In this photo, the counterbrockage date is located in an offset position south of the original date.

More information on this error can be found at this link:

http://www.coinworld.com/news/us-coins/2015/10/collectors-clearinghouse–several-ways-to-a-

Rim-restricted Second Strikes

Part VI. Striking Errors:

Weak Strikes:

Rim-restricted Second Strikes

Description: A second strike in which minimum die clearance has increased to such an extent that the dies only touch down on the design rim.  Second strikes of this nature must also be off-center strikes.

Rim-restricted second strikes can be confused with similar-looking but unrelated striking errors.  If it’s only slightly off-center, a rim-restricted second strike will look very much like a case of rim-restricted design duplication.  The latter is a form of machine doubling in which the hammer die (it’s nearly always the hammer die) bounces off the surface of the coin, shifts to one side, and lands lightly on the design rim.  If the second strike is significantly off-center, then a rim-restricted second strike can be confused with a double strike in which the first strike is off-center and minimally expanded while the second strike is centered.

01a_weak_ds_2005_1c_obv copy01b_weak_ds_2005_1c_rev  01c_weak_ds_2005_1c_IGW copy 01e_weak_ds_2005_1c_UN copy01d_weak_ds_2005_1c_ONE copy

This 2005 cent received a normal first strike and a slightly off-center rim-restricted second strike.  Unlike a case of rim-restricted design duplication, die-struck design elements are present on both faces.

02a_rim-restricted_2nd_stk_1992P_25c_obv02b_rim-restricted_2nd_stk_1992P_25c_rev
02c_rim-restricted_2nd_stk_1992P_25c_obv_close copy 02d_rim-restricted_2nd_stk_1992P_25c_rev_close02e_rim-restricted_2nd_stk_1992P_25c_edge

This 1992-P quarter received an abnormally strong first strike that caused finning of the design rim on the left side.  The second strike is about 75% off-center, rotated 90 degrees clockwise, and die-struck on both faces.  Second-strike design elements are almost completely restricted to the design rim.  On the reverse face, the only recognizable second-strike feature is the design rim.  No interior design elements are present on the reverse because much of the resistance to the impact of the hammer die was provided by a slightly elevated collar.  This simultaneously softened the impact of the anvil die so that no details managed to strike up.  DR2 = 2nd Strike Design Rim

Edge Lettering Applied After Strike: Lettering Die Inclusion

Part VII. Post-Strike Mint Modifications:

Edge Lettering Applied After Strike:

Lettering Die Inclusion

Definition: Foreign matter that is forced into the edge of a manganese-brass clad dollar coin by the lettering die.  Such errors may be difficult to distinguish from foreign matter forced into the edge of a planchet during the upsetting process.  The main difference is that a lettering die inclusion will protrude from the coin’s edge while an upset mill inclusion will be flush with the edge.

 01a_lettering_die_inclusion_edge01b_lettering_die_inclusion_obv

This 2007-P Jefferson dollar has a spiral metal shaving embedded in its edge.  Strongly attracted to a magnet, it’s probably composed of steel.  The right arm of the U of PLURIBUS is deeply impressed into the metal shaving because of the latter’s tight fit against the lettering die.  Discovered by Troy Shoopman.

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