Can someone explain to me how mahine doubling occurs? What does this do to the potential value of the error? Thank you. PD13
machine doubling occurs when a 'part' slips during the imprint... this causes the gosted image (not the best explanation, i know lol). The easiest way to tell a true doubling to machien doubling, is to look at whats called the 'seriffs'. These will split, and look like 2 distinct letters ro numbers. In the image above, they all join back to the same starting point. machine doublin adds nothing, nada, ziltch to the value of a coin.
Think of machine doubling this way - - - the dies come together to strike the planchet between them. A moment after the coin is struck the dies start to pull apart and one "chatters" (moves slightly). The sideways motion of this "chattering" die shears off a portion of the raised portions of the just struck coin. This is what causes the "terraced" look. Machine doubling is not an error. As daggarjon noted, machine doubling does not increase the value of a coin and in some cases may decrease a coin's value.
See other threads and posts See other threads and posts on true doublED dies versus other forms of doubling or The Chapters in Cherry Pickers Guild. The very best way I have devised so far on how to explain machine doubling is - The dies or luggs holding the dies become loose from pounding, then when the dies strike a coin there is a flopping together when they strike the planchet, or as it is ejected, (ejection doubling) (because they are loose) and then a portion of the design is doubled by a scooting, pulling or pushing of the metal creating an extra image. If you were able to see a thousand or more coins right after the dies (and before they tightened the equipment) became loose you would see some progression of doubling becoming more pronounced as the dies gave way to more play, (became looser). On true doubled dies the doubling will be same and the only thing that will ever change is the die state as the die (doublED die ) wears more and more. Hope this helps,
