Unusually severe examples of die wear are uncommon and generally reflect a failure to remove a die in a timely fashion. The current America the Beautiful quarter dollars series is known for poor-quality strikes caused by heavy die wear.
Most ring-shaped defects are tiny and centrally located, like the circle that surrounds the Lincoln statue on the reverse face of the illustrated 2004 Lincoln cent. However, precise positioning varies from die to die making diagnosis difficult, and whatever made the irregular, closely-spaced hexagonal rings on one die is especially beyond imagination.
Weak strikes caused by excessive minimum die clearance (the most common proximate cause) vary in how far the dies sink into the planchet or coin. Since the design rim is usually the highest point on a normal coin, it may be the only area in which a second strike delivered by insufficiently approximated dies can be seen.
Most orphan off-metal errors are one-off events. The presence of two nearly identical examples struck on solid copper-nickel blanks suggests there may have been some planning involved The first comes from error dealer Jon Sullivan and weighs 4.81 grams. It has two very thin, partially worn-through patches of embedded copper-colored material on the reverse face....
How do modern overdates occur? Several explanations and causes may be at play.
Major horizontal misalignments of the anvil die are exceedingly rare. Such misalignments necessarily involve the collar as well, since the latter confines the neck of the anvil die. The collar either has to break apart or break free of its moorings. Even rarer are coins that display major horizontal misalignments of both dies.
Die fill is a combination of various factory-floor elements — think metal dust and filings, and heavy grease — that can end up on the surface of a die. The material can fill the recesses of a die where, under the impact of striking coins, it eventually becomes quite hardened. What happens if, during the heat of striking, it expands beyond the surface of the die face?
Only normal-sized coins are likely to make their way into rolls, so most error finds are of kinds that don’t change a coin’s size, such as doubled dies, clashed die errors, and grease strikes. Roll searcher Steve Smith recently discovered a more unusual combination of striking errors, which still left the coin its normal size and allowed it to slip undetected into a roll...
When a collar die breaks the results may differ. Mike Diamond breaks down what you should be checking for.
A collar break (“collar cud”) is expected to appear in the same spot on the edge of every coin struck within that collar. Such is indeed the case for every known 20th and 21st century collar break — except this one.