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Dropped letter error on Polk $1

A 2009-P James K. Polk Presidential dollar with dropped “T” letter on the edge has been found by John Morris of Florida.

This article was originally printed in Numismatic News.
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A 2009-P James K. Polk Presidential dollar with dropped “T” letter on the edge has been found by John Morris of Florida.


The inverted “T” from either the word TRUST or PRESIDENT is only the second example of a dropped letter on the edge of a Presidential dollar that has been sent in by Numismatic News readers since the inception of the Presidential dollar series in 2007.

A dropped letter” is a relatively rare error type with its origins in the common filled die error. When debris, (often referred to by error collectors as “mint goop” or “grease”), clog a die, it may after a few strikes, become compressed within specific cavities of the die such as numerals or letters even after the offending material has been removed from the fields of the die through the repetitive process of striking coins.

In this case, a letter “T” was clogged. Later, the offending material fell out of the “T” recess in the die like Jello from a mold. It fell into the coining chamber and onto the collar. The coin was then struck, impressing the T-shaped goop into the edge.

After the strike, the foreign material fell off out of the edge of the coin, resulting in a perfectly shaped inverted and incuse (recessed) letter “T” struck into the coin’s edge just in front of the Philadelphia “P” mintmark. The fact that it may appear raised in the photo is an optical illusion.

Most dropped letters, (or numerals or other areas of design), are typically found on the obverse or reverse of a coin, but extra careful attention to the edges on edge-lettered coins (such as the Presidential series) has resulted in dropped letter errors being found on the edges in recent years (though the number of reports is still very small). The increased use of horizontal coin minting presses may also be a factor since gravity would increase the chances of this occurring where it was less likely with the traditional vertical style minting technology.

It needs to be pointed out that extra characters found on the edges of Presidential dollars (and now the Native American dollars) have been extremely common. This common error type is unrelated to the dropped letter type and is typically seen as an extra character (or sometimes two) found on the edge of the dollars in random places just like this one, but with a different effect. The common type appears to be the result of an incoming smooth-edge coin entering the edge-lettering die while another coin is in a jammed position a bit further down in the die. When the incoming coin butts up against the jammed coin, force is exerted between the edges of the two coins and one of the incuse characters from the outgoing coin can act like a die and raise a letter onto the incoming coin’s edge as the pressure between the two coins builds up to a point that the jammed coin is finally freed up and ejected or a technician clears the machine.

A diagnostic of this type of error is that it will be a slightly raised character as opposed to the incuse character of a dropped letter. This raised character appears to have been flattened closer to the field like a pancake. This flattening of the raised character is thought to occur when that area of the edge of the coin is passing through the edge-lettering machine to complete the edge inscription and the shoulder of the edge-lettering die smashes the original height of the “extra character” down.

I show one of these flattened characters on the edge of a 2007-P George Washington dollar so you can see a mirror image of a raised “S” flattened down almost level with the field butted up to the right side of the “B” of PLURIBUS.

Be careful when a dropped letter on edge is being offered for sale. It is very rare while the extra letter error from a jam up in the edge-lettering machine is exceedingly common.

New information has come my way since I featured in the Dec. 22, 2009, issue of Numismatic News a 2008-D Martin Van Buren Presidential dollar with a dropped letter from the obverse impressed into the edge of the coin. While the errant letter was correctly described for the error type that it represented, I did make a wrong call on its point of origin. I suggested that the randomly placed incused “A” originated from a grease filled “A” from the reverse.

However, eagle-eyed reader Stanislaus W. Pekala noticed that the font and size of the errant “A” was not a match for any of the “As” on the reverse but was a perfect match for any of the “As” in Martin Van Buren’s name on the obverse.

Numismatic News readers send in scores of questions every week. One anonymous reader e-mailed the following question: I have the book Strike It Rich With Pocket Change and I’m a coin collector. I found a couple of suspicious coins. I do not know if this is the right place to send them for your comments, but here is what the coins are: 1968-D cent with a faded “8” in 1968, 1978 “silver” dime and a 1994 “silver” cent.

In answer, the faded “8” is most probably the result of die abrasion or a lightly filled die of which neither rarely adds much value. Nonetheless, while minor, they are fun to find and collect since the price is right when found in circulation.

The “silver” dime and “silver” cent are most likely the result of being plated after the coins left the Mint. Tens of thousands of coins are plated for novelty purposes every year for use in items ranging from little girls charm bracelets to “pennies in a bottle” to paperweights. If the weights of the coins are normal or nearly so and appear properly struck in all other respects, they are probably altered in this manner. If not then further investigation is needed.

Edward S. of Michigan asked: “How collectible is a proof 1992/1992 Washington quarter? I have enclosed a picture of the doubled date. Neither myself or my coin dealer expert can find any information about it.”

This coin appears to exhibit Strike Doubling on the date (showing lightly to the west of the primary characters) and also on the upper portion of the “V” of Washington’s bust. Strike Doubling, also known as Machine Doubling and Mechanical Doubling, is not a doubled die or repunched date nor any kind of die doubling.

Strike Doubling is a form of doubling that occurs within a split second after the strike and/or during ejection due to vibrations set up in a press somewhat like vibrations in a car with broken motor mounts can cause the contents of your tool box to chatter. Strike doubling is random in its effects just depending on how the finished coin bounces or otherwise makes contact with the die(s) and may affect each coin being ejected from a press differently than the next in strength and areas affected.

Most specialists do not generally consider this form of doubling an error or a variety even though it looks like one. This is because it occurs after the strike and not prior to or during the strike. For most United States coins the minting process ends after the striking of the coin and thus anything that occurs after is not a Mint error or variety (though some changes may be regarded as ‘Official Mint Modifications’). The only exceptions are when a coin needs to be processed by more than one press or is struck again after it has been damaged.

Coins such as all the Presidential dollars and Native American dollars (since 2009) are all run through a second press (known as a Schuler Edge Lettering Machine) and most everything that occurs to the edge during that process is also an error.

Ken Hintz sent an e-mail with an attached image of the reverse of a 1910 Liberty Head nickel that he said: “looks like metal had flaked off before struck, because the strike is there. What do you call this and is the nickel worth much more?”

The missing metal is due to lamination caused by impurities or gas in the planchet. In this case the metal was actually there during the strike and fell off later. The effects of the strike actually alter the internal areas of metal more than many might think. If the metal were missing prior to the strike less design detail (or none) would be present due to the lack of metal to fill the dies as the coin was struck.

As for value, lamination errors are not as popular as some of the other error types unless very dramatic and on higher grades. In this case my guess is that it would add a few dollars to the normal numismatic value of the coin. While this is not a windfall by any means, it is still an error and certainly collectible.

Ken Potter can be reached by sending a long, self-addressed envelope with 61 cents postage to P.O. Box 760232, Lathrup Village, MI 48076, or by e-mail at An educational image gallery may be viewed on his website at

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