Hey guys. Lately i have have been researching a lot about errors. I was always under the impression that a doubled die occurs when a coin is punched, and then instead of fully ejected is moved over a tiny bit and punched again. If this is wrong please please please correct me. But if this is right how are there multiple doubled dies for single dates. Take the '55 doubled die cent. If this is a rare occasion where the coin is barely moved over instead of ejected, how could there be soooo many '55 doubled dies.
What you're describing is not a doubled die. Here's a good reference to understand how a doubled die occurs: http://www.coinresource.com/articles/doubled_dies.htm This is Ken Potter's site and has great explanations for all types of doubling, collectible and otherwise: http://koinpro.tripod.com/Articles/OtherFormsOfDoubling.htm
First, coins are struck, not punched. (Dies strike the planchet. Past-tense of strike is struck.) A coin that is struck and stays in the coining chamber to be struck again is called a double-struck coin. The 1955 DDO Lincoln Cent is a doubled-die coin. You may need to study up a bit on the coin-making process but very simply the dies used to strike coins (called 'Working Dies') used to require several hubbings before they were complete. The hubbing process is where a hub (positive image of the coin) is pressed into a die blank to make a die (or vice versa). Between each hubbing the die blank was removed to be annealed. When the die blank (and the hub - if it was removed) was placed back in the hubbing machine if the die and the hub were not precisely aligned a doubled die could be produced. The features (lettering, numerals, devices, etc.) previously pressed into the die is offset from the latest one creating a doubling of those features. So the doubling is part of the die and every coin struck by that die will have the doulbing.
