Error Token Info

An error coin is a coin that was manufactured incorrectly by a mint. Many times called mint errors, error coins come in scores of "shapes, sizes and types." The sheer variety of minted errors adds excitement and uniqueness in collecting them.

Errors can be the result of defective planchets, defective dies or the result of mistakes made during striking. The planchet, die, and striking (or PDS) classification. Some errors have multiple causes and not all errors fall neatly within the categories.

Some errors, such as an off-center strike, are unique. Other errors, such as those resulting from a specific die crack, form a variety, i.e., a group of coins with distinctive details or characteristics. Uniqueness does not necessarily make an error coin valuable. Accidental error coins are perhaps the most numerous, although in modern minting they are rare, making them potentially valuable to collectors. Intentional intervention by mint personnel does not typically involve a deliberate attempt to create an error, but usually involves an action intended to improve quality that miscarries.

Clipped Planchet

A misfeed can occur when the metal strip is fed through the blanking machine. The punches sometimes overlap the leading edge of the metal producing a straight clip. Sometimes, the punches strike an area of the strip which overlaps the hole left by the previous strike producing a curved clip. On such curved-clip coins, often the rim opposite the clip shows a distinctive distortion and loss of detail called Blakesley Effect. Sometimes punches strike the irregular trailing edge of the metal strip producing irregular clips.

Improper Planchet Thickness

Coins are sometimes struck on planchets that are either too thin or too thick producing underweight or overweight coins. This error can be due to incorrect equipment settings causing the metal strip to be rolled to the wrong thickness or due to the use of a metal strip intended for another coin denomination, such as a U.S. quarter planchet cut from a metal roll intended for dimes.

Lamination Flaw

A lamination flaw is a planchet defect that results from metal impurities or internal stresses. Lamination flaws cause discoloration, uneven surfaces, peeling, and splitting.

Split Planchet

A split planchet coin error occurs when, during the preparation of the planchet strip, impurities such as gas, dirt, or grease become trapped under the surface of the metal blank, creating a weakness or lamination defect. This weak area of the metal may flake, peel, or split because the adhesion is poor.

Split planchet errors are normally restricted to planchets composed of a solid alloy. Split planchet errors should not be confused with "separation errors", which only affect clad and plated coins. Separation errors are bonding errors, not alloy errors.

A split can occur either before or after the coin is struck. The descriptive terms split before strike and split after strike are used to distinguish the respective types. A "split before strike" will show design on both sides of the coin, have coarse to fine striations, and will usually be weakly struck. A "split after strike" will show a normal strike on one side, but will have a rough, design-free surface on the other side and will always weigh less than a normal planchet.

Hub and Die Errors

Mints use hubs bearing raised images similar to the images that appear on a coin to imprint indented images onto the ends of steel rods. Those rods become the dies which strike planchets making them into coins. Hub and die errors can occur at the time the dies are made, when the dies are installed into presses, and from die deterioration during use. Modern coins can still be released with hub and die errors when the defects are too small to be seen with the naked eye. Sometimes, dies are used despite producing obvious flaws.

Missing Design Elements

Missing mintmarks, dates, and other design elements occur as the result of errors in the die or at the time of striking. A design element that is missing from the die when it is made is a fundamental error. Missing design elements that occur because dies are tilted and do not strike the planchet face-on are known as misaligned dies. A design element may be missing because foreign matter, such as grease, plugs the cavity into which the planchet's metal would normally flow under the striking pressure. This error is also known as a filled die or a strike through. Although this does involve a die, it is typically thought of as a striking error, but is included here for completeness.

Doubled Die

A doubled die occurs when a die receives an additional, misaligned impression from the hub. Overdate coins such as the 1942/1 U.S. Mercury dime and 1918/7 U.S. buffalo nickel are also doubled dies. They are both listed by CONECA as class III doubled dies. Class III means the die was hubbed with different "designs" (or hubs that had different dates). They are not repunched dates, since the dates were punched onto the hub. Die deterioration may also appear as doubling.

Die Defects: Cracks, Breaks, and Chips

Dies can crack during use producing jagged, raised lines on the surface of subsequently struck coins. Dies with cracks, especially those with cracks near the edge, sometimes break. The broken piece may be retained in position or fall away. Die cracks and retained die breaks can be difficult to distinguish. Retained die breaks cross the coin's face from rim to rim with the area to one side of the break being slightly higher than the other. Coins struck after the break falls away have a raised, rounded, unstruck area along the edge. These coins are known to collectors as cuds. Sometimes, an area of a die will chip out of the center. These so-called die chips also appear as raised, rounded, unstruck areas on subsequently struck coins.

Die Clash

A die clash occurs when the obverse and reverse dies are damaged upon striking each other without a planchet between them. Due to the tremendous pressure used, parts of the image of one die may be impressed on the other. Planchets subsequently struck by the clashed dies receive the distorted image.

Misaligned Dies

Dies must be properly aligned in presses for coins to be struck correctly. Errors occur when dies are offset, tilted, or rotated. Offset errors occur when the hammer die is not centered over the anvil die typically resulting in an off-centered obverse, but centered reverse. Tilting errors occur when die surfaces are not parallel producing coins that are thinner along one edge, and sometimes causing missing design elements along the opposite edge because of insufficient pressure being exerted on that edge. Rotation errors occur when the images on the obverse and reverse dies are turned from the normal positions such as when the reverse image is at a right angle to the obverse.

Strike Errors

Strike errors occur when the planchet is struck. It is a fault in the manufacturing process rather than in either the die or the planchet. Numismatists often prize strike-error coins over perfectly struck examples, which tend to be more common, but less highly than die-error coins, which are usually rarer, making them valuable.

Broadstrike

Broadstrike errors are produced when the collar die (the circular die surrounding the lower die) malfunctions. The collar prevents the metal of the blank from flowing outside the confines of the die. All denominations of U.S. coins with a broadstrike have plain edges.

Strike Through

A "strike-through" coin is made when another object comes between a blank and a die at the time of striking. That object's outline is pressed into the blank's surface. Common examples include hard objects such as staples, metal shavings, and other coins as well as soft objects such as cloth and grease. Hard objects leave sharp outlines and, on occasion, adhere to the blank producing a coin called a "retained strike-through". A planchet "struck-through" a coin is left with an impression of the coin called brockage (discussed below). When the "strike-through object is a blank planchet the result is a uni-face coin with one struck side and one blank side (see below). When the "struck-through" object is another coin, and that coin adheres to a die(as opposed to the other coin), the adhered coin is called a "die cap" (discussed below). Two coins which adhere to one another are called "bonded pairs". Softer objects, such as grease, can fill crevices in a die, producing a weak strike with a smudged appearance. These errors are often called "missing element coins" (discussed above and as "filled dies").

Uni-Faced Coin (Blank Reverse)

A uni-face coin results when two planchets are stacked one atop the other at the time of striking. This produces two coins: one with only an obverse image, and a second with only the reverse image. The planchets may be centered over the die producing one complete image on each coin or off-centered producing partial images on each side. In the accompanying image of the blank reverse, the shadow or outline of Lincoln's profile from the obverse side of the coin is visible.

Die Cap

A struck coin remains on a die and leaves its slowly fading impression (called brockage) on subsequently struck coins and, over time, changing shape to resemble a bottle cap.

Brockage

Brockage occurs when a mirror image of a coin is struck on a blank. After a struck coin fails to eject, a new blank is fed between the struck coin and the hammer die. The hammer die strikes the second blank leaving its image on one side while pressing the blank against the previously stuck coin which sinks its image into opposite side. Most brockages are off-center, but fully overlapping brockages are the most desirable.

Edge Strike

There are two types of edge strikes. A standing edge strike occurs when a blank "bounces" so that it is standing on edge as it is struck. Striking pressure produces edge indentations where the dies strike, and sometimes bends the blank. Repeated strikes can produce a coin that is folded flat. . Chain edge strikes occur when two blanks are fed into the space between dies at the same time. The blanks expand when struck and press together leaving each with single indented edge. Two chain edge struck coins together are known as a matched pair.

Multiple Strike

A multiple strike, also referred to as a double exposure, occurs when the coin has additional images from being struck again, off center. The result is sometimes mistaken for being a "doubled die". On occasion, a coin will flip over between strikes so that the second image is that of the opposite side of the coin.

Off-Center Strike

An off-center coin is produced when the coin is struck once, albeit off center. Unlike a broadstrike, the punch is not in the center of the coin, but rather the edge. This results in a coin which is not circular. The coin gives a freakish appearance as a result, and various amounts of blank planchet space are visible. The coins can vary in value because of how far off center they are struck, although coins with full dates are more desirable than coins without a date or missing digits.

Struck On Wrong Planchet

Sometimes planchets for one coin denomination are fed into a coin-stamping press equipped with dies of another denomination. This results in a coin that has been stamped with a design intended for a differently sized coin. The resulting errors are prized by collectors, though they are usually caught during the manufacturing process and destroyed. Such errors are sometimes called "double denomination" coins, but that term is also used to refer to coins struck a second time with dies of a different denomination.

Edge and Rim Errors

Blanks are surrounded by collars when struck to prevent the blank from flattening and spreading. Edge and rim errors occur when collars are either out of position or are deteriorated. A wire rim occurs when excessive pressure squeezes out metal between the collar and the edge of the die producing an extremely high thin rim. A partial collar occurs when an out-of-position collar leaves a line around the coin which is visible when looking at its edge. A partial collar is sometimes called a railroad rim when a reeded edge coin is involved as the line resembles a rail and the reeds resemble railroad ties.

Mated Pair or Set

A collection of two or more coins struck at the same time or during successive strikes on one or more dies, these coins with the resulting errors are related to one another, fitting together as a set. All brockages, indents, chain edge strikes, and capped die strikes have a corresponding coin, but are rarely found together. A single coin of the set may be discovered by mint staff during quality control and removed, or the coins may be separated into different lots to be distributed separately into circulation.