PART V. Planchet Errors:

Lamination:

Lamination loss after strike:

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

PART V. Planchet Errors:

Lamination Errors:

Lamination on Clad Coins

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 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 II. Die Varieties:

Large and Small Mintmark Variations

Definition: This occurs when two different size mintnmarks for the same mint are used in the same year on the same denominational coin.

In 1928, two different S mint marks were used for the Lincoln cent minted out of San Francisco. It is surmised that one of the S mint mark punches broke and a substitute was used. The image to the left shows a “small” S mint mark, which is the more commonly found for this year. The image to the right shows the “large” S mint mark which is less common.

The 1945 Winged Liberty dime also saw the use of two different S mint marks during the same year. The image to the left shows the more common mint mark, while the image to the right shows the less common “micro” S mint mark.

PART II. Die Varieties:

Large Over Small Mintmarks

Definition: A smaller size mintmark is first punched into a working die.  It is followed by a large mintmark bearing the same letter(s).

The image below shows an 1879-CC Morgan Dollar, minted in Carson City, Nevada.  A larger CC-mintmark was punched over a smaller CC-mintmark. This is known as 1879 CC, VAM 3 and 3A.

Image is courtesy of VAMworld.

PART IV. Die Errors:

Lathe rings

Definition: These concentric rings are produced by a lathe which shapes the cone-shaped face of the unfinished working die.  The cone is supposed to be polished smooth before hubbing.  If polishing is omitted or inadequate, the surface will remain covered by concentric lathe marks which will not be erased by subsequent hubbing.

Concentric rings can be seen near the rim under the word TRUST down to the date.

Lathe rings seen on a 1984-P Lincoln cent.

PART X. Wastebasket / Composite Categories:

Longacre’s Doubling

While Longacre’s doubling is most associated with the Indian Head Cent. It is also found on the Seated Liberty denominations and other coins of that era.

There are two theories for Longacre’s doubling. The first, which is most popular, is that the master die was placed into the die steel to form the master die. To add details to the die, the engraver would then shave the sides of the punch used to add design elements, leaving a lip on that punch’s sides. The engraver would then conduct an extra hard hit to the punch leaving the shaved sides effects into the die. The effect would eventually wear off as the master die did age, which is why not all coins from a particular working die would have the Longacre’s doubling.

This is the second scenario. After adding the design elements to the master die, the engraver would move the punch slightly and tap it again. This would produce a ‘lip’ on the die, and the effect would make the metal flow into the punched in design elements more readily. In theory, this would also have prolonged the die’s life.

The image below shows Longeracre’s doubling on the word UNITED on an 1883 Indian Head Cent.

While the subject and study of abnormal reeding has been around for two or more decades, this sub category focuses on a coin of recent vintage, a 2008-P New Mexico state quarter. First, however, a brief history of reeding variants.

One of the best known examples is the “infrequently reeded” 1921 Morgan dollar. A rather extensive discussion of this variant can be found on pages 113-144 of Frank Spadone’s “Major Variety and Oddity Guide to United States Coins” (8th edition). Spadone notes that there are only 154 reeds versus the normal 188 reeds found on other silver dollars produced in 1921. He further observes that the grooves between the reeds are simple slots rather than the more elaborately defined notches seen in other dollars. He suggests it represents a first attempt at fabricating a collar for a denomination that hadn’t been minted for 17 years.

A very uncommon cause of abnormal reeding is collar damage or improper machining. Both Arnold Margolis and Alan Herbert report the use of a broach to create the ridged working face of the collar. A broach is a cylindrical tool with longitudinal ridges that is hammered or driven into a smooth, unfinished collar to create the ridged working face. A worn or damaged broach, or the improper penetration of broach, can theoretically produce abnormal reeding. It’s quite possible that other techniques are periodically used to create the ridged working face. It would be a simple matter to cut evenly-spaced grooves into the working face with a machine tool.

This rather roundabout introduction leads us to the focus of our entry – a 2008-P New Mexico quarter with abnormal reeding. The reeding on this quarter takes the form of low, thin ridges separated by broad, flat valleys. A normal quarter shows taller, wider ridges separated by deeper, V-shaped valleys. The ridges on the working face of the collar were ground off almost to their bases.

An essentially identical error is known on a 1964-D quarter.

Below is a 2008-P New Mexico quarter. The left image displays normal reeding. The right image displays abnormal reeding. Center image is a comparison edge view of both the normal and abnormal reeding.

http://www.coinworld.com/articles/a-second-case-of-abnormal-reeding-on-a-state

PART VI. Striking Errors:

Machine Doubling

Definition: This form of doubling typically results from vibration or instability affecting the die, die assembly, or press frame.  It has also occasionally been blamed on a coin sticking to the anvil die during ejection (“ejection doubling”).

Machine doubling has many synonyms: mechanical doubling, machine doubling damage, machine damage doubling, ejection doubling, shift doubling, and strike doubling.

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There are three basic forms of machine doubling:

Push doubling:  Push doubling occurs when a die bounces off the surface of the coin, shifts position, and lands lightly in a different spot.  A diagnostic feature is marginal shelving at the edges of design elements.  Interior features often show rounded doubling that is easily mistaken for the effects of a double strike or a doubled die.  Push doubling can occur on either face, although its most dramatic expressions tend to appear on the face struck by the hammer die.  Cases of push doubling can involve up to three closely-spaced sets of accessory design elements.  Push doubling can occur on both faces simultaneously and often in different directions.  Up to three different doubling directions can be represented on a single face.

Slide doubling:  In this form of doubling, a die drags itself through the newly-struck design, smearing the features.  Strong cases of slide doubling are always restricted to the face struck by the hammer die.  After reaching the lowest point of its downstroke, the hammer die shifts to one side without bouncing.  As it drags itself across the newly-struck design, it piles coin metal into a series of ridges.  Weak cases of slide doubling found on the reverse face have previously been assigned to “ejection doubling”, but there is no way to prove that this is actually what happened.

Rim-restricted design duplication: This rare form of doubling has to date only been detected on Presidential dollars (Washington to Madison), 1994 cents (several die pairs), a 2004 cent, and certain quarters and dimes where the peripheral letters hug a very narrow design rim.  It always occurs on the face struck by the hammer die.  After reaching the lowest point of its downstroke, the hammer die bounces up, shifts to one side, and lands lightly on the design rim, leaving a set of raised design elements.  It is also sometimes referred to as “one-sided, rim-restricted design duplication”.

The images below show “Push” machine doubling.

PART VI. Striking Errors:

Machine Doubling:

Machine Doubling in More Than One Direction

Definition: Up to three different directions (north, south, east and west) of machine doubling can be seen on the same face of the coin. This multiple direction type of machine doubling should not be confused with Longacre’s doubling.

The 1991-P Lincoln cent shows three directions of machine doubling. The first image to the right has machine doubling on the east side of Lincoln’s bust.

The same coin’s date has machine doubling on the south side of the digits as shown in the image to the left.The  image to the right of the same coin shows machine doubling on the north side of the RTY of LIBERTY.

PART VI. Striking Errors:

Machine Doubling:

Machine Doubling on Both Faces of the Same Coin

Definition: This form of doubling typically results from vibration or instability affecting the die, die assembly, or press frame.  It has also occasionally been blamed on a coin sticking to the anvil die during ejection (“ejection doubling”). At times, machine doubling can affect both the obverse and reverse face of the coin.

This 1991(P) Lincoln cent has been affected by machine doubling on both the obverse and reverse faces of the coin.

The 1991(P) Lincoln cent pictured above may have been struck by the same dies as the 1991(P) Lincoln cent shown first. Both the obverse and reverse of this coin show exaggerated shelf-like machine doubling.

This coin is courtesy of Cindy Helms.