In 1982, the Philadelphia Mint produced a small quantity of dimes without a mintmark, the first such error to occur on a coin made for circulation. This inconceivable error came about thanks to a Mint employee who failed to add the mintmark onto an obverse die. Traditionally, Mint employees punch the mintmark into working dies, which are then inspected for any flaws or omissions. In this case, the omission of the mintmark went unnoticed and thousands of 1982 dimes without mintmarks escaped from the Philadelphia Mint that year.

The 1982 No Mintmark dimes were first discovered in late December, 1982. Credit for the discovery is shared by Walter Placzankis, Andrew Macdonald and Lane Durkee. The largest concentration of these error coins was in the area around Sandusky, Ohio, where approximately 8,000 to 10,000 of them were found. All of the coins from the Sandusky area display strong strikes with a date separated from the rim of the coin. Many of the error coins were given out as change to visitors at the Cedar Point Amusement Park. Additional error coins eventually turned up in circulation.

In August 1983, more 1982 No Mintmark dimes were reported in Pittsburgh. The original estimate for this hoard was in the 3,000 to 5,000 range. The coins from this hoard were weakly struck, as opposed to the strong strikes found in Sandusky. On the weakly struck examples, the number "2" of the date is weak and closer to the rim when compared to the well-struck examples.

Both varieties of the "Weak" and "Strong" 1982 No P Mint Mark Dimes were traced to mint bags that came from the Federal Reserve Bank of Cleveland. Later, additional 1982 No Mintmark dimes were found in the Boston area, giving the indication that at least part of the Cleveland shipment ended up in Boston. Most of the uncirculated examples were retrieved directly from the Citizen's Bank or from some of the dealers who purchased them from local bank tellers. The discoveries were pinpointed to three major locations, thus providing some very crucial clues as to how many coins were released.

A prominent Toledo coin dealer by the name of Clyde Englehardt owned about 1,500 of these error coins at one time; this is the area where most of the coins were found. Clyde, who has been dealing in coins since 1960, is also mentioned in Walter Breen's Encyclopedia of U.S. Coins.

When we interviewed Clyde, he reminisced about the early 1980s, just as the coins were being discovered and how the local dealers and bank tellers would offer him 1982 No Mintmark dimes by the roll! He also preserved different inserts and periodicals relating to the 1982 No Mintmark dimes over the years that were very helpful for this article.

In 1987, Clyde donated examples to the American Numismatic Association and the Smithsonian Institution. He never found a 1982 No Mintmark Dime in circulation, but that never stopped him from buying them. He also made some very keen observations on the Weak and Strong varieties. For example, he discovered that only 47 to 48 sharply stuck 1982 No Mintmark dimes fit inside a plastic dime tube as opposed to 50 to 51 weakly struck examples fitting in the same tube. Coincidentally, Clyde is the guardian of two very significant coins, each notable because it illustrates a very distinguishable die crack at 1 o'clock on the obverse. The die crack provides additional clues as to how many of these errors were created in 1982.

Many experts believe the Weak 1982 No Mintmark dimes were created before the Strong versions. It is very possible that a mint employee noticed the weakly struck examples early in the production process, then increased the striking pressure to obtain a better and stronger strike (resulting in the Strong variety). The die cracks on Clyde's coins may have been the result of the increased pressure. Once this damage was noticed by the press operator, the die would have been pulled and discarded, thus ending the production of 1982 No Mintmark dimes.

In 1982, the expected life of a single die pair was 75,000 circulation strikes, placing an upper limit on the mintage of the 1982 No Mintmark dimes. However, if the increased striking pressure caused the dies to crack prematurely, the actual mintage might be significantly lower.