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BROCKAGE & Broadstrike errors

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A mirror image of a coin has been struck on both sides of the planchet. This error typically occurs when a coin remains on either die after striking. (The planchet wraps around the bottom die like a soda bottle cap and remains in place.) The second coin receives the image from the die, though its blank other side also receives the image of the struck coin. The result is an incuse mirror image, and the coin is known as a brockage error.




Broadstrike errors are produced when the collar die malfunctions. The collar is the circular die surrounding the anvil (lower) die. It applies the edge device (reeded edge, plain edge) and prevents the metal of the coin being struck from flowing outside of the confines of the die. When the collar is prevented from working properly during striking, it may rest below the surface of the anvil die. All denominations of U.S. coins with a broadstrike have a plain edge.

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[font:Comic Sans MS]1999 Delaware State Quarter Dollar 50% Obverse Brockage and Broad Struck Error[/font]



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These errors happen when a struck coin remains on either die after strike, and impresses its image into the next blank planchet, as its struck, leaving a negative/mirror image.



A brockage error can only occur when there are two coins involved. One of the coins involved will always be a struck coin which has not ejected properly. That struck coin will find its way back between the dies and will be struck next to a blank planchet which was fed into the collar. The image of that first struck coin will be impressed into that side of the blank planchet. The result will be a second coin which has images of the first coin impressed into it. Those images will be pressed into the coin and the image will be in reverse. This incuse sunken image is known as a brockage.



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As dramatic as other errors might be, few are as surreal as the brockage; one side is perfectly normal, but the other side is a mirror image of the first, with the features sunk into the coin instead of raised and the lettering reversed. A brockage results from a glitch in striking. In the modern minting process, a blank planchet is fed between two dies, one lower die or anvil die that does not move, and one upper die or hammer die that is raised and lowered. (The terms anvil and hammer are holdovers from the time when coins were made by hand. A heated planchet was placed on the lower die, the upper die went on top of the planchet, and the broad top surface of the upper die was struck with a mallet or hammer.)


Normally, a planchet goes between the two dies, receives an impression, and then the newly minted coin is ejected to make room for the next planchet. Rarely, though, a newly minted coin sticks to one of the dies. When the next planchet comes in, instead of being struck by two dies, it gets its design from one die and one coin. The coin-as-die is in positive relief, so it gives the planchet a negative impression, and since the coin-as-die shows the side opposite that of the die to which it is stuck, the brockage side of the error mirrors the normal image.


In the case of this 1918 brockage dime, a coin stuck to the reverse die, and this piece was then struck with the obverse die, which created the normal impression, and the obverse of the coin-as-die, which is responsible for the mirror image. Both sides are well-centered and show sharp impressions of Miss Liberty but relatively weak letters and numbers; interestingly enough, the word LIBERTY and the date are more clearly defined on the brockage side. Though this dime is dated (twice!), the mintmark is missing, and where this error was made remains a mystery. Its absence, however, will hardly dampen error collectors' enthusiasm for this double-headed treat.


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