What it is
A wrong planchet error is a coin struck on a blank meant for another denomination or alloy, such as a cent struck on a dime planchet or a 1943 cent struck on a bronze blank.
What causes it
Leftover blanks stuck in bins or tote bags were fed into the wrong press.
How to identify it
- The coin's weight and color do not match the denomination.
- A smaller planchet leaves part of the design missing.
- Weight is the key test: compare with the official weight for both coins.
How to tell it from damage
Plated coins change color but not weight. Always weigh a suspected wrong planchet coin.
Famous examples
How a blank ends up in the wrong press
Each press is set up for one coin, with dies and a collar sized for its planchets. Blanks travel from the annealing and cleaning lines to the presses in large bins and tote bins. A wrong planchet error happens when a stray blank from one job is caught in a corner of a bin, conveyor or feeder and is carried into a press making another coin. The stray blank is struck like any other, but it does not match the dies.
If the stray blank is smaller than the correct planchet, it drops into the collar and receives a full-force strike but covers only part of the die. If it is larger, it cannot fit in the collar and is usually struck out of collar, off-center or crumpled. The Mint keeps blanks for different coins apart and inspects bins between jobs, so modern wrong planchet errors are scarce.
Types of wrong planchet errors
Collectors separate several kinds. An off-metal error is struck on a blank of a different alloy, such as a cent on a dime planchet, a nickel on a cent planchet or a quarter on a nickel planchet. A transitional error is struck on the previous or next year's alloy when the Mint changed metals, such as a 1943 cent on a bronze blank, a 1944 cent on a steel blank or a 1965 quarter on a 90% silver blank. A foreign planchet error is struck on a blank made for a coin the Mint produced for another country.
Two related errors are collected alongside them. A wrong stock error is struck on a blank of the correct alloy but punched from strip of the wrong thickness. A double denomination is struck on a coin that had already been struck as another denomination, so traces of the first design show under the second.
Famous wrong planchet coins
The 1943 bronze Lincoln cent is the best known. In 1943 cents were struck on zinc-coated steel to save copper for the war, but a few bronze blanks left over from 1942 were struck with 1943 dies at Philadelphia, Denver and San Francisco. The opposite case, the 1944 steel cent, came from steel blanks left over when the Mint returned to a copper alloy. Both are rarities.
The 1965 changeover to copper-nickel clad produced 1965 quarters and dimes struck on 90% silver blanks left from 1964. The 2000-P Sacagawea dollar mule, which pairs a state quarter obverse with the dollar reverse, is sometimes called a wrong planchet error, but it is a die-pairing error struck on the correct dollar blank.
Weights and sizes that settle the question
A digital scale reading to a hundredth of a gram is the most useful tool. Standard weights are 3.11 grams for a copper cent, 2.5 grams for a copper-plated zinc cent, 2.7 grams for a 1943 steel cent, 5.0 grams for a nickel, 2.268 grams for a clad dime, 2.5 grams for a silver dime, 5.67 grams for a clad quarter, 6.25 grams for a silver quarter and 8.1 grams for the small-size dollar coins.
A cent struck on a dime planchet should weigh about 2.27 grams and look silver-gray. A 1965 quarter on a silver blank should weigh about 6.25 grams rather than 5.67. Diameter helps too. A smaller wrong planchet leaves part of the design missing around the edge and the coin stays close to the size of the blank it was punched for. For 1943 and 1944 cents, a magnet is the quickest first test, because steel sticks and bronze does not.
Fakes and look-alikes
Plating is the most common trick. Cents plated with silver or nickel look like wrong planchet errors but weigh the same as a normal cent and often show the plating wearing through at the rim. Copper-plated 1943 steel cents are sold as bronze 1943s. A magnet exposes them at once. Another fake 1943 bronze cent is a 1948 cent with the 8 altered to a 3, which is why the shape of the 3 must match genuine 1943 dies.
Genuine wrong planchet coins show a crisp, full-pressure strike on the part of the blank that met the dies. Where the dies missed a smaller blank, the original edge and upset rim of that blank are still intact.
Grading and attribution
Grading services name the planchet on the label, for example struck on a dime planchet or struck on a silver planchet. Because transitional coins such as the 1943 bronze cent are heavily faked, collectors buy them only certified and grading services may test the metal before they attribute one.
Frequently asked questions
What causes a wrong planchet error?
Leftover blanks stuck in bins or tote bags were fed into the wrong press.
How can I tell a wrong planchet error from damage?
Plated coins change color but not weight. Always weigh a suspected wrong planchet coin.
How do I know if my coin was struck on the wrong planchet?
Weigh it and compare with the standard weights for both the coin and the planchet you suspect. Color, a magnet test for 1943 and 1944 cents and a partly missing design on a smaller blank are further clues.
Is my 1943 copper penny real?
Probably not, because most are copper-plated steel cents or altered dates. A genuine 1943 bronze cent does not stick to a magnet and weighs about 3.11 grams.
Why is part of the design missing on a wrong planchet coin?
The blank was smaller than the dies, so the outer part of the design had no metal to strike. That is normal for a coin struck on a smaller denomination's planchet.