Any bimetallic coin can have its core flipped. It's surprisingly common to find Canadian $2 coins that have been core-flipped.
A bimetallic coin is made of two separate pieces of metal. Different metals react differently to temperature, expanding and contracting at different rates. So exposing the coin to either extreme heat or extreme cold (which one works depends on the properties of the two metals in question) can loosen the core enough to allow it to simply pop out. Then you can put it back in backwards, upside-down, sideways or whatever. As with many "fake errors", it's even entirely possible that such things are made "accidentally", by someone whose coin fell apart on them and they reassembled it without paying any attention to which way around it "should" have been. The coin gets spent and the next person to pay attention to it "discovers" what they assume to be some kind of error coin.
Quote:
What other bogus errors are out there? Does anyone have any useful tips?
The most useful tip is, of course, what you have already discovered: to become familiar with how coins are actually made, so that you can look at a coin with an "error" and fail to imagine any possible way the coinage process can go wrong in such a way as to produce that error.
For example: one-sided coins are a common "fake error". But a coin is made by pressing a blank piece of metal in between two coin dies. A genuine "one-sided error", where one side is perfectly normal and the other side is perfectly smooth and flat, is as logically impossible to create in the mint as the sound of one hand clapping. To create a genuine one, someone in the mint would have had to deliberately create a blank die, specifically to create a one-sided coin. This usually only happens for experimental patterns and trial pieces. Now, there are things that can fall in between a die and a planchet that you might think could create a "one-sided coin", but they tend to create other kinds of errors - a brockage, for example, is made when a coin fails to eject, gets stuck in the die and the next coin is struck with the first coin still stuck in the die. Or, if two blanks fall into the press at the same time, one on top of each other - this creates two "one-sided coins" of a sort, but because there's twice as much metal between the dies as there's supposed to be, the surplus metal tends to squirt out all over the place and the resultant coins look entirely unlike a fake "one sided coin", which is usually made simply by grinding down one side of a perfectly normal coin with a grinder of some kind.
Likewise, "two-headed coins" are rare and valuable errors when genuine, but are commonly and fairly easily faked. Making one in the mint is nearly impossible because the dies used for obverses and reverses for coins are usually not interchangeable; they deliberately make them from differently shaped pieces of metal to fit into different shaped slots in the press; the square peg on the obverse die won't fit into the round hole of the reverse die-slot on the press. They do this specifically to make it difficult for an inattentive mint worker to accidentally put the wrong side in the wrong place. Most fake double-sided errors are "
Magician's coins", trick coins made so a coin-tosser can call heads and win every time; these are made by taking two perfectly normal coins, grinding one coin down until it's just a thin one-sided disc and grinding out a shallow bowl-shaped hole into the other side of the second coin just big enough to accept the disc. The tell-tale to look for is the gap between the disc and the bowl, often carefully hidden inside the rim on one side.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
Posted 05/29/2014 11:06 am
