alexbq2 Posted February 3, 2012 Report Share Posted February 3, 2012 This was posted on one of Russian coin forums, I hope that topic starter will not mind me sharing his images. Look at the coin below. See the mirror images of the flip side ghosting on both obverse and reverse. This looks exactly like a die clash, but the 'foreign elements' are not concave! It looks like there is a mirrored coin imprint on both dies. And this is not the only coin with this type of error - http://coins.su/forum/index.php?showtopic=80670&st=0. Any ideas? Link to comment Share on other sites More sharing options...
constanius Posted February 3, 2012 Report Share Posted February 3, 2012 Perhaps the coin was struck then flipped over & struck again, leaving traces of the first strike(obverse) under the second strike(reverse) & visa versa. Or maybe the planchet was of a recalled worn coin and the reverse of it was struck by the obverse die etc. Edit: Looking & reading again, "the mirror image" does rule out both my suggestions. Link to comment Share on other sites More sharing options...
constanius Posted February 3, 2012 Report Share Posted February 3, 2012 The only "foreign" parts showing through to the othersides are located in the same general area. Pehaps the planchet was extra thick in that one area & the excess material was forced to the other side causing this effect. This also does not seem very likely Link to comment Share on other sites More sharing options...
BKB Posted February 3, 2012 Report Share Posted February 3, 2012 Mirror image also kills the theory of an old die being reused. somehow this is a result of die clashing. I do not know how it could happen, because the details are not concave, however, the only possible explanation of a mirror image design on the die would be a result of clashed dies. But, why the details on the coin are not concave, I do not know... Link to comment Share on other sites More sharing options...
alexbq2 Posted February 3, 2012 Author Report Share Posted February 3, 2012 Here's a theory proposed on the Russian forum. Dies were damaged through a die clash, then repaired by filing of convex imprints "foreign elements", this removed some of the tempered hard steel from the top layer specifically in the pattern of the die clash damage. The dies kept being used, and the softer parts of the die got hammered inwards a bit forming a concave pattern on the die, which started striking these mirrored convex elements onto the coins. Does that hold water from the metallurgic and minting perspective? Link to comment Share on other sites More sharing options...
constanius Posted February 3, 2012 Report Share Posted February 3, 2012 Sounds very plausible. Link to comment Share on other sites More sharing options...
bobh Posted February 3, 2012 Report Share Posted February 3, 2012 Look at the coin below. See the mirror images of the flip side ghosting on both obverse and reverse. This looks exactly like a die clash, but the 'foreign elements' are not concave! It looks like there is a mirrored coin imprint on both dies. And this is not the only coin with this type of error - http://coins.su/foru...pic=80670&st=0. Any ideas? I must have misunderstood something, but the ghost imprint of a clash should be convex, not concave, I think? (i.e. concave = depressed, convex = raised). Or did you mean something else by concave? Link to comment Share on other sites More sharing options...
alexbq2 Posted February 3, 2012 Author Report Share Posted February 3, 2012 I must have misunderstood something, but the ghost imprint of a clash should be convex, not concave, I think? (i.e. concave = depressed, convex = raised). Or did you mean something else by concave? It's convex on the die, but concave on the coin. Link to comment Share on other sites More sharing options...
BKB Posted February 4, 2012 Report Share Posted February 4, 2012 The elements on the coin are raised. That is the problem here. Otherwise, simple die clash... I do not know about the fill in theory. What the hell do you use to "fill in" those traces of die clash?! Link to comment Share on other sites More sharing options...
alexbq2 Posted February 4, 2012 Author Report Share Posted February 4, 2012 The elements on the coin are raised. That is the problem here. Otherwise, simple die clash... I do not know about the fill in theory. What the hell do you use to "fill in" those traces of die clash?! I didn't say "fill in", I mean die clash damage was filed off from dies. Link to comment Share on other sites More sharing options...
BKB Posted February 4, 2012 Report Share Posted February 4, 2012 When you grind off the field (cannot file it off), you take off a lot of design elements. In reality, you may have to redo the whole die, if you loose enough. That is why it was not done and we see all those traces of die clashes. On the other hand, even if you do it, why would it create this effect? Link to comment Share on other sites More sharing options...
constanius Posted February 4, 2012 Report Share Posted February 4, 2012 When you grind off the field (cannot file it off), you take off a lot of design elements. In reality, you may have to redo the whole die, if you loose enough. That is why it was not done and we see all those traces of die clashes. On the other hand, even if you do it, why would it create this effect? Because, the theory goes, inadvertently when you file off the hardened surface of the die in the removal of the convex impression left by the die clash you leave that exact area softened & each time the die then strikes another planchet the area which has had the hardened surface removed becomes minutely more & more depressed. So what was the convex impression, because of the removal of the hardened layer of the die, becomes a depressed concave impression. Link to comment Share on other sites More sharing options...
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