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<p>[QUOTE=&quot;19Lyds, post: 1082889, member: 15929&quot;]To answer your question, yes, an error occurred in the die making process which is what allowed the coins you refer to, to be created. There are some interesting stories regarding these coins which you&#039;d be wise to research.</p><p>&nbsp;</p><p>Now some details:</p><p>&nbsp;</p><p>Before the 1990&#039;s, when dies were created, they went through multiple steps.</p><p>&nbsp;</p><p>Once a design is approved for production, a galvano gets created which then went to the reducing lathe which reduced the 6&quot; Galvano design down to an exact duplicate of what the coin will look like. This was an engraving process which took upto 48 hours to complete and the end result was whats called a Master Hub. Hubs have positive relief exactly like coins.</p><p>&nbsp;</p><p>The Master Hub gets heat treated and hardened.</p><p>&nbsp;</p><p>The Master hub then would be used to create a Master Die. Dies all have negative relief. However, instead of engraving, master dies are made in hydraulic presses where the hub gets pressed into softened die steel. Mutliple impressions are needed in order to insure that all the design elements are impressed into the Master Die. Each step consists of pressing the die then removing it from the press, heating it to soften it, then reinstalling it in the press for another impression. IF, the Hub and Die are not perfectly aligned during any step of this process, then a Master Doubled Die gets created. Once the Master Die gets created, it gets sent to the engraver who then engraves the date onto the die.</p><p>&nbsp;</p><p>The Master die is now used to create Working Hubs in the exact manner that the Master Die was created. A Master Die can create hundreds of working Hubs and again, each time a Working hub is softened and reinstalled for reimpression, it must be perfectly aligned or a Doubled Working Hub will be created.</p><p>&nbsp;</p><p>Each working Hub is now used to create Working Dies. These are the dies used in the coining presses and each Working hub can create hundreds of working dies and again if any of the softened dies are not perfectly aligned during the repressing step, then a doubled die gets created.</p><p>&nbsp;</p><p>The working dies get stamped with the Mint Mark and then are ready for the production presses.</p><p>&nbsp;</p><p>To minimize alignment problems, the US Mint uses aligning keys on Hubs and Dies however as with anything, sometimes the aligning keys get honked up with the end result being a doubled die. </p><p>&nbsp;</p><p>In the case of the 1955/55 and 1958/58 and 1969/69 Lincolns, the doubling represents whats called Rotated Hub Doubling. This type of doubling occurs when the receiving die gets rotated slightly (around a central pivot point) during the hubbing process. The amount of rotation, on some hub doubled dies, is less than a degree and in many cases, less than half a degree.</p><p>&nbsp;</p><p>Other types of doubling can occur during this process and these include Distorted Hub Doubling, Design Hub Doubling, Offset Hub Doubling, Pivoted Hub Doubling, Distended Hub Doubling, Modified Hub Doubling and the last (and newest form) Tilted Hub Doubling. Pickup ANY numismatic book regarding current coinage with varieties and errors and each of these doubling types is explained in detail.</p><p>&nbsp;</p><p>So...how did doubled dies get produced? Easy, mistakes happen and even though its not noted above, every step in the process is checked for quality including the actual minting process of the coins. </p><p>&nbsp;</p><p>Obvious errors are discarded.</p><p>Not so obvious errors can get through.</p><p>&nbsp;</p><p>I hope this answers your questions and encourages you to do more research.[/QUOTE]</p><p><br /></p>

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