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 Replies: 10 / Views: 1,975 |
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Pillar of the Community
Hong Kong
1270 Posts |
Bought this Trade dollar in 2016.7 from ebay and find it different with my other pieces, it is 26.11gr and 38.6mm in diameter,0.4mm smaller from standard and about 0.8gr lighter. Very odd to me... Let you see it is real or struck by different die and smaller planchet. Please comment...    Edited by wonghinghi
08/09/2020 06:02 am
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Pillar of the Community
 Hong Kong
1270 Posts |
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Bedrock of the Community
Australia
21786 Posts |
The specifications you give for diameter and weight suggest to me that it could be a
pressure die cast copy.
Same manufacturing techniques have been used for the production of diecast zinc metal toys (eg scale model cars), for many decades.
There is a tiny amount of shrinkage after a metal object has been cast. The lack of any suggestion of radial mint luster on a coin in this condition can also suggest that it may be pressure diecast.
Density and alloy composition should be investigated.
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Pillar of the Community
Hong Kong
1270 Posts |
  It looks the 1899 piece had two dies, this piece has no dot after the year and no triangle at the ship. @sel I don't understand what is pressure diecast. I compare the first trade with this normal one (26.82gr, 39.0mm), the hitting sound and tested by neodymium magnet, both give the same effect. I am quite confident that the first coin is made of silver. Do you mean the first coin is fake? |
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Bedrock of the Community
 United States
12477 Posts |
Quote:
Do you mean the first coin is fake? That's the suggestion, I believe. Just because it may be silver doesn't mean it's genuine. In Memory of Crazyb0 12-26-1951 to 7-27-2020
In Memory of Tootallious 3-31-1964 to 4-15-2020
In Memory of T-BOP 10-12-1949 to 1-19-2024
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Pillar of the Community
Hong Kong
1270 Posts |
That is a really excellent counterfeit!
I query why the counterfeiters needed to make another die for a fake?
Is it a contemporary counterfeit?
Or I just imagine would the mint officer cheated by using some small planchet for his own profit.
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Pillar of the Community
United States
1912 Posts |
These coins are faked and plentiful in large numbers. Mine came from China.
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Pillar of the Community
United States
5362 Posts |
These are modern numismatic forgeries not contemporaneous circulating counterfeits. The edge shows the signs of a post casting application using a tapered ring die. They are well finished but not Worth more than melt value of the metal used. In the US they should be countermarked "COPY" to comply with the Hobby Protection Act of 1973.
Pressure die casting also known as centrifugal casting is a technique used by jewelers to create small intricate castings. The procedure has been used by modern forgers for years. The casting mold is normally a flexible plastic or rubber that can resist high heat. There are images pressed into the pair of plastic molds so that one injection of metal produces 6 to 12 coins. The metal is forced into the mold while the mold is spinning. This fills even the tiniest crevasses. There are good descriptions of the technique on line.
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Pillar of the Community
Hong Kong
1270 Posts |
Thank you all your opinion.
If both coins are fake, I am eager to see a real of this type. Anyone can share?
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Bedrock of the Community
Australia
21786 Posts |
At this stage, I am not saying the coin is fake,
because I don't know enough about it.
That is why I do suggest that further investigation is required. Some of that further suggestion of same comparative ping tone certainly helps with authenticity.
What I don't understand is why it is 0.4mm less in diameter. Casting shrinkage is consistent with what has been found here. Perhaps? some genuine coins are quite legitimately 0.4mm less in diameter, but I don't know enough about this subject.
There a number of good videos on the manufacturing of diecast (mostly zinc) metal toys. Few or no casting bubbles or surface roughness are seen in these products.
XRF testing may not help, because it could be silver plated, if? not genuine.
Edited by sel_69l
08/11/2020 11:12 pm
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Pillar of the Community
Hong Kong
1270 Posts |
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Replies: 10 / Views: 1,975 |
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Posted 08/09/2020 08:57 am
