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 Replies: 36 / Views: 6,104 |
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Pillar of the Community
United States
2740 Posts |
This is a very common form of post-strike damage, and it's not predicated on the presence of a fin beforehand. Percussive impacts along the edge and rim generate a thin apron of metal that migrates over the die-struck design elements. You see this all the time on Dryer Coins, but it's not restricted to Dryer Coins. Error coin writer and researcher.
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Pillar of the Community
United States
5964 Posts |
It was here, Pennyman, my Blanking Burr.  |
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Pillar of the Community
United States
1781 Posts |
The rim is rounded and obviously "worked" indicating it was spun in some kind of rotational devise.
Edited by koinpro
05/11/2015 10:38 pm
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Pillar of the Community
United States
1781 Posts |
Mike, After seeing the images of the edge it's clear this not from a wire-edge (what I call finning) being flattened down, but please explain why it is restricted primarily to the right side of the obverse, why it's only on the obverse and why the coin is still of normal diameter. I still want to believe PMD from a rotational devise but I no longer believe from a dryer as I'd expect the effect to be nondiscriminatory as to the obv/rev or right or left side. You have studied these in far greater detail than I have. I haven't even measured the diameter of one b4. In any event, please offer a more detailed analysis. Edited by koinpro
05/11/2015 10:45 pm
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Pillar of the Community
United States
2740 Posts |
I can't offer a more detailed analysis because I've never seen the process that generates the damage. It's certainly conceivable that the metal was relocated as the coin was rolled and squeezed in a mechanical device. In the end it really doesn't matter as it's clearly post-strike damage. It's important to note, however, that the same sort of damage can occur on blanks and planchets before the strike. But in those cases the thin apron has well-struck letters on top of it and the apron is flattened to the level of the field (except in those cases when it lifts up after the strike). I've reported on several cases in Coin World. http://editions.amospublishing.com/...ing%20damageError coin writer and researcher.
Edited by mikediamond
05/11/2015 11:09 pm
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Pillar of the Community
United States
1781 Posts |
Mike, it's clear that it is PMD but I was just hoping you could clarify a bit more on the specifics as they apply to this coin -- if you had any other ideas. I'm curious. Anyway, the answer may just unfold at some point down the road. A friend of mine has a planchet with the upset rim like this. It can occur to a planchet when the rimmer is set to tight (as I'm sure you know). You can also see a similar effect on some of the Adams dollars that were run through the edge lettering machine set too tight. You may know that the edge lettering machines the Mint uses can also upset rims. If Mint is on a budget they are used for both operations but can only do one operation at a time. The edge inscriptions are applied after the coin is struck at the US Mint but that that is not the way the manufacturer recommends edge lettering be applied. You may find this of interest: http://koinpro.tripod.com/Articles/...brochure.pdf |
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Pillar of the Community
Canada
2632 Posts |
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Pillar of the Community
United States
1781 Posts |
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Pillar of the Community
  United States
1998 Posts |
Thanks everyone for the responses and education. I am going to hold on to this example for future reference
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Pillar of the Community
United States
2740 Posts |
It's doubtful that the upset mill can generate a thin apron along the perimeter of a planchet. Narrow spacing in the upset mill only generates a tall proto-rim but no apron. It is probably some other piece of machinery. Goodness knows, planchets have to travel through many pieces of equipment before they arrive in the striking chamber.
I've seen four other cents with struck-in aprons, indicating that this is not a one-of event.
Error coin writer and researcher.
Edited by mikediamond
05/12/2015 11:25 am
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Pillar of the Community
United States
1781 Posts |
Mike, you are correct in that the effect would not be identical on my friend's planchet to what we see here. I'll have to look at it again as it has been over 25 years. As I look back it seems to me there may have been two planchets involved that piggy backed their way in. Again, I'll have to look.
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Pillar of the Community
United States
1781 Posts |
Now that I think about it, it was an off center coin I saw with this effect (or similar). It showed on the unstruck portion of the planchet. Was this a coin that you wrote about Mike? If so what were your determinations? The effect on my friends planchet is entirely different. I mixed it up with the Off Center I saw somewhere.
Edited by koinpro
05/12/2015 11:11 am
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Pillar of the Community
United States
2740 Posts |
I would suggest you read the Coin World article I linked to, along with earlier column on abormal forms of upset cited within that article. Error coin writer and researcher.
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Pillar of the Community
United States
1781 Posts |
Thanks Mike! You positioned the link to that article so far down from the body of your post that it appeared to be a part of a signature and I never saw it. Very interesting article. In any event, maybe I missed it, but did you get the diameter of the so-called " Dryer Coin"? I'm interested in following this effect further in trying to learn more about the causes. On the Off Center, this one is plain strange. Do you own the coin or have larger images I can see? I have an idea but really need to see the surfaces in far greater detail. |
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Pillar of the Community
United States
2740 Posts |
I'll send you enlarged photos of the off-center nickel. It is really strange-looking, although its weight, dimensions, and composition match that of a nickel planchet. I did not record the diameter of the " Dryer Coin". I believe I still have it, so I'll dig it out and get you the measurements. Error coin writer and researcher.
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Posted 05/11/2015 10:10 pm
