The way that fake double-headed and two tailed coins are made is not what you'd expect, why many people find them are reluctant to accept the truth about them. They are not made by two coins cut in half and then attacked the mid, why don't you see a seam along the edge giving away money. Instead, two-headed coins are made from outside hub at the center of a coin, intact jagged edges and heads side and then shaving down a second currency, so that it fits snugly inside the shell of the first. You need a fair amount of skill in working to this end, not to mention all the appropriate instruments, but the result is a clever trick that is difficult to detect with the naked eye.
If you use a strong magnifying glass to look very carefully along the rim of the side of the coin double-headed, first or else you will see a very thin line around the circumference of the coin. This line is not on the edge of the coin; is actually on the front (or backwards) very close to the brim. This is where currency shaven down you inserted the empty shell of the other.
If, after having carefully examined the two-headed coin or two-tailed, still not convinced that is an element of novelty, take it to a dealer of currency and ask him to show you how it is made. One thing is certain, that was not done in this way by the Mint of the United States!
The Mint US (and most other mints of the world) have protections against the currencies that have inappropriate or rotation die die accidentally installation. The tree of moulds are made to be of a certain size and shape, so that they fit only in Polish press a certain way. Molds which have their design "heads" (or front) have trees of a shape (perhaps square), while the moulds with the "Code" (or reverse) have a different shape tree (maybe round). Because don't put a tree in a square hole round, this prevents workers from mint coins making accidentally double-sided (or two-tailed).
