Part III. Die Installation Errors:

Use of Canceled and Defaced Dies

Definition: When a die is pulled from service it is first defaced before being sent out to be recycled.  When a design is retired, the remaining dies are canceled or defaced so that no further coins can be struck.  Installation of a canceled or defaced die is unlikely to be an accident and the coins struck by them must be considered intentional errors.

A coin struck by canceled dies will still show most of the design, but the surface will be crossed by one or more thick ridges that may run in parallel or may intersect.  These ridges represent grooves cut into the die face.

A coin struck by defaced dies will show little of the design. Surface details are replaced by a coarsely textured or lumpy surface.

No examples exist of coins struck by canceled or defaced dies within the U.S. Mint.  Several examples are known from other countries. These include a bimetallic 1994 Hong Kong 10 dollar coin with two parallel ridges on each face.  We also have the unique Egyptian coin described below.

This Egyptian 25 piastres planchet was first struck 80% off-center by 25 piastres dies.  It was then struck within a 50 piastres collar by a pair of 2010 Egypt 50 piastres dies that had most of the design ground off.  The defaced 50 piastres dies only contacted the unstruck portion of the off-center 25 piastres coin.  The struck tongue was left untouched by the second strike because its reduced thickness was apparently less than the minimum die clearance of the 50 piastres press.

The 50 piastres reverse die was rotated approximately 120 degrees counterclockwise relative to the obverse die (medal rotation is normal).

The 25 piastres denomination is struck on a planchet composed of nickel-plated steel while the 50 piastres design is normally struck on a planchet composed of brass-plated steel.  We therefore have in this double-denomination error the rare trifecta of a planchet error (off-metal/wrong planchet), a die error (defaced), and a striking error (off-center first strike and rotated die error on second strike).

Part IV. Striking Errors:

Foreign Object Chain Strike

Definition:  A conventional chain strike occurs when the expanding edges of two adjacent discs of coin metal (2 planchets, 2 coins, or one of each) meet and flow together.  A foreign object chain strike occurs when the edge of a coin metal disc and the edge of a foreign object meet and flow together.  Right now, the only recognized foreign object chain strikes involve one member of a pair of feeder/ejection fingers that extend from the same feeder arm.  These errors can therefore also be classified as a form of machine part impingement. Foreign object chain strikes involving other intrusive elements would be hard to recognize, unless they left a tell-tale residue on the edge of the coin or if they left the chain-struck edge with a very peculiar shape and/or texture.

The vast majority of foreign object chain strikes co-occur with a form of intra-strike damage at the opposite pole produced when the protruding portion of the off-center coin is pushed into the other feeder/ejection finger.

Most foreign object chain strikes are seen in multi-struck coins.  These are invariably struck by inverted dies installed in the high-speed Schuler press.

This off-center dime shows a foreign object chain strike on the right side.  Here the edge of the dime and the internal edge of a feeder/ejection finger met and flowed together.  The edge of the dime is slightly convex and bears a 13 millimeter long contact facet.  The opposite pole was pushed in when the protruding portion of the off-center coin was pushed into the other feeder/ejection finger. This form of intra-strike damage almost always accompanies a foreign object chain strike.  The two together form a pattern of bilateral machine part impingement.

This quadruple-struck nickel shows a foreign object chain strike on the right side.  Here the expanding edge of the nickel met the expanding edge of a feeder/ejection finger, leaving the former with a relatively straight edge.  At the opposite pole we again see impact damage from the other feeder/ejection finger.

Part VI. Striking Errors:

Machine Part Impingement

Definition: This error occurs when a coin is pinned and pinched between two machine parts during the strike.  For modern US coins struck with inverted dies in a high-speed Schuler press, the two machine parts are paired feeder/ejector fingers that form the arms of a notch that cradle the planchet and (subsequently) the newly-struck coin.  The feeder/ejection fingers lie at the expanded tip of feeder/ejector arm that looks like a wrench.  Each “wrench” is one of many that fit into a rotating plate that fits the definition of a rotary or dial feeder.

Machine part impingement errors are associated with off-center strikes and with double- and multi-struck coins in which most of the strikes are off-center.  When the dies strike the off-center planchet or coin and the off-center feeder that cradles it, the two elements expand radially.  The facing edges flow together, leaving the coin with a convex facet we call a “foreign object chain strike”.  The portion of the planchet or coin that projects outside the striking chamber is pushed laterally by the expanding coin metal and expanding feeder metal.  The pole opposite the convex facet collides with the other arm of the feeder/ejector, leaving the edge of the coin with a dent and often a warped surface.

This off-center dime was pinned and pinched between two machine parts.  The right side of the coin shows a gently convex foreign object chain strike.  Here the expanding edge of the dime collided with the expanding internal edge of the feeder/ejection finger.   At the opposite pole, the unstruck portion of the dime was pushed laterally into the other feeder/ejection finger.  This collision pushed in the planchet’s edge, warping the unstruck portion of the dime.  This is an example of intra-strike damage.

This quadruple-struck nickel was pinned and pinched between two feeder/ejection fingers during the last three strikes.  After a normal first strike, the nickel received three closely-spaced off-center strikes that are well-separated from the initial strike.  This is a typical pattern for multi-strikes suffering from machine part impingement.  It’s almost certain that the misplaced and mistimed feeder/ejection arm prevents the coin from leaving the striking chamber entirely.

On the right side there is a long, relatively straight contact facet that represents a foreign object chain strike.  Once again, the culprit is one of the two feeder/ejection fingers that cradle the coin.  The left side of the coin was pushed in when the portion of the coin lying outside the striking chamber was pushed into the other feeder/ejection finger.

Part IV. Die Errors:

Clashed Dies:

Raised Clash Marks

Definition:  Clash marks are generated when dies collide in the absence of a planchet.  Each die transfers part of its design to the opposite die in the form of faint, raised, normally-oriented design elements.  Clash marks are generally confined to the field portion and shallowest devices of the die face.

While clash marks are expected to appear on a coin as incuse, mirror-image features, there are exceptions, both real and apparent.

Raised clash marks may occur in the event of a relatively light collision.  If, on the die face, a narrow strip of field is situated between two relatively broad elements, only that narrow strip will make an (incuse) impression on the opposite die.  The coin will therefore show a correspondingly raised, mirror-image design element.

Two “flames” erupt from the roof of Monticello on this 1983-P nickel.  They represent a pair of identical, offset, raised clash marks that depict the gap between Jefferson’s neck and queue (“ponytail”).

The reverse face of this 2001-P Vermont quarter dollar shows a raised clash mark that has been whimsically interpreted as a vapor cloud emerging from the maple-tapper’s mouth.  The “winter breath” clash mark is actually the area where Washington’s wig meets his neck.

Raised clash marks are also the inevitable result of a clash involving design elements intended to be incuse on a coin.  The corresponding features on the die face are therefore raised, and they will penetrate the opposing die in the event of a clash.  The resulting incuse, normally-oriented accessory design elements will be transferred to a coin as raised, mirror-image design elements.

The reverse design of the New Hampshire quarter contains the incuse legend OLD MAN OF THE MOUNTAIN.  When transferred to the obverse die, they appear on the coin as raised, mirror-image letters.  On this particular 2000-P New Hampshire quarter, behind Washington’s inverted head. we find the letters (OL)D MA(N) on the top line and (O)F TH(E) on the next line.

The 1975 cent shown displays an early-stage counterbrockage of the obverse design on the obverse face. It was produced when an obverse die cap with a brockage of the obverse design on the reverse face struck a succession of planchets, this being one of them.

Machine parts above collar can impede expanding

coins

By Mike Diamond | May 21, 2011 10:00 a.m.
Article first published in 2011-05-30, Expert Advice section of Coin World

An off-center cent with a “sideneck strike.” Driven toward the northeast by the expanding die-struck portion of the coin, the unstruck edge collided with the side of the adjacent hammer die neck.

Images by Mike Diamond.

As a coin is struck, its expansion is abruptly halted by the surrounding collar.

When the collar fails to deploy, a coin expands in all directions. As a result, all off-center strikes and broadstrikes are wider than a normal coin, to varying degrees.

On some occasions a coin’s expansion is impeded, and the edge damaged, by machine parts positioned above the collar plate.

The most familiar obstacle to unfettered expansion is the neck of an adjacent hammer die. In a dual or quad Bliss press (the last of which was retired in 2005), the close proximity of adjacent die pairs results in the occasional production of a “sideneck strike,” also referred to as an “almost saddle strike” or a “one-die saddle strike.”

A typical example is shown here in an off-center Lincoln cent. At the pole opposite the 1 o’clock position of the obverse face, we see a deep, concave notch and an associated pressure ridge. The planchet represented by this coin lay partly within one striking chamber and almost managed to encroach on the adjacent striking chamber. In other words, the coin fell just short of becoming a “saddle strike.” When struck, the expanding die-struck area pushed the unstruck portion toward the adjacent striking chamber. It collided with the side of the hammer (obverse) die neck as the latter was striking its own coin.

Sideneck strikes are always concave and always closest to the adjacent striking chamber. In most years, this chamber would lie along a line drawn from the 1 o’clock position in Lincoln cents, or the 11 o’clock position in Jefferson 5-cent coins and Roosevelt dimes.

Strike-related edge damage of another kind is seen in an undated Jefferson 5-cent coin. The pole opposite the off-center strike has a flat, vertically oriented contact facet. It appears that the facet was produced when the unstruck portion of the planchet was pushed south by the expanding die-struck area and collided with a machine part. Another possibility is that the coin was hit while momentarily immobilized by the two dies.

In either case, we can’t be sure what machine part was responsible, although I suspect a feeder finger. I’ve encountered these flat facets on quite a few off-center and double-struck cents and 5-cent coins. In each case, the strike is about 70 percent off-center and the contact facet lies opposite the base of the bust.

The introduction of the Schuler press introduced new types of strike-related edge damage. This press uses a single die pair, with the reverse die operating as the hammer die. The damage is primarily associated with multi-struck coins. A representative example is provided by a quadruple-struck 5-cent coin. The first strike was normal. The other strikes were delivered about 20 percent off-center and are closely spaced. Edge damage is present on both the right and left sides. The contact facet on the right side is convex, slightly beveled, and extends from 12 o’clock to 2:30.

The dies evidently struck whatever machine part rested against the coin. On the left side the coin buckled when it collided with a hard object. The contact facet here is quite compact and lies next to the w of we. It’s possible that the coin was pushed laterally into an obstruction by expansion produced by the off-center strikes. It’s also possible that an object hit the coin as the latter was temporarily immobilized between the dies.

This type of edge damage can be found on numerous multi-struck cents, 5-cent coins, and Washington quarter dollars struck by Schuler presses. The pattern is consistent, although the long facet and the short facet can be located on either the right or the left side.

The affected coins all show a sequence of strikes involving a normal (or at least centered) first strike, and one or more closely spaced off-center strikes. Coins in which the off-center strikes are widely spaced or erratically positioned typically do not show this edge damage. The long facet that hugs the edge of the off-center strikes is almost certainly caused by contact with a feeder finger. I’m not sure about the short facet.

Coin World’s Collectors’ Clearinghouse department does not accept coins or other items for examination without prior permission from News Editor William T. Gibbs. Materials sent to Clearinghouse without prior permission will be returned unexamined. Please address all Clearinghouse inquiries to cweditor@coinworld.com or to (800) 673-8311, Ext. 172

http://www.coinworld.com/articles/machine-parts-above-collar-can-impede-expandi/

Copyright 2012 by Amos Hobby Publishing Inc. Reposted by permission from the March 22, 2012, issue of Coin World.)

PART V. Planchet Errors

Blanking and Cutting Errors:

Ragged clips:

Definition: A coin with a ragged clip has its circular outline interrupted by a very irregular edge.  Ragged clips are traditionally thought to be derived from the unfinished leading or trailing end of the coin metal strip.  While these ends are supposed to be trimmed, this step can be accidentally (or intentionally) skipped.

While ragged clips are sometimes referred to as “end of sheet” or “end of strip” clips, this same area is also a likely source for straight clips (see Straight Clip).  Therefore the term “ragged clip” is preferred.

Ragged clips can also be derived from the middle of the strip.  As the strip is rolled out, ragged fissures sometimes develop. If a blanking die slices through such a fissure, the resulting blank will have a ragged clip indistinguishable from one derived from the ends of the strip.

The shape of a ragged clip is highly variable.  Many are straight, some form “ragged notches” and some turn into “ragged fissures”.

The edge texture of a ragged clip is invariably rough and shows some graininess

Ragged clips are sometimes confused with broken coin and broken planchet errors.

The three images below are a 1985 Indian 25 paise struck off-center with a ragged clip planchet. The lower image isan oblique angle of the grainy edge of the ragged clip.

PART II. Die Varieties:

Wrong Date:

Date Later Than Final Issue:

1913 Liberty Head nickel

Definition: A coin carrying a date later than the last official date for the issue.

Washington quarter obverse with a 2000P Sacagawea

dollar reverse.

Debuting in May of 2000, this slip up was destined to make history. At the time, it was the only known “mule” coin in United States history.