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 Replies: 20 / Views: 2,358 |
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Pillar of the Community
United States
1721 Posts |
Edited by mds308
07/26/2023 09:48 am
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Moderator
 United States
56855 Posts |
Please keep us updated. John1  |
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Pillar of the Community
United States
1048 Posts |
Cool find! Hope it passes muster.
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Pillar of the Community
Canada
1527 Posts |
 I look forward to seeing the results. |
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Bedrock of the Community
United States
73795 Posts |
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Moderator
United States
95018 Posts |
could be roller lines, Is that copper showing on the reeded edge?
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Moderator
United States
95018 Posts |
were 71's 40% silver? I thought that stopped in 1970.
Is that why we see some copper on the edge? A plated coin?
It was in 1975-1976 that they went to 40% silver for the Bicentennial.
EDIT: to fix a silly typo.
Edited by Dearborn
07/26/2023 3:29 pm
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Pillar of the Community
 United States
1721 Posts |
Quote:
were 71's 40% silver? I thought that stopped in 1970.
Is that why we cee some copper on the edge? No. 71's should not be silver but there are known examples made using the wrong planchet. The copper, or what appears to be copper, is intermittent. Some areas of the reed look silver. I'm hoping it's a double error. |
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Bedrock of the Community
United States
10034 Posts |
There is copper showing on the edge in some of the pictures. THis could have been plated at one time. The weight of a 40% is 11.1 to 11.9.
A clad can be 10.8 to 11.7g. So it is within tolerances of clad also.
How much squash could a Sasquatch squash if a Sasquatch would squash squash? Download and read: Grading the graders Costly TPG ineptitude and No FG Kennedy halveshttps://ln5.sync.com/dl/7ca91bdd0/w...i3b-rbj9fir2 |
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Pillar of the Community
United States
7174 Posts |
 closer to clad than 40%. |
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Bedrock of the Community
United States
19126 Posts |
At a glance, the coin appears to have been plated. Wonder what that feature is coming off of Kennedy's bust, pointing to the 7.
Edited by ijn1944
07/26/2023 3:27 pm
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Pillar of the Community
United States
3207 Posts |
if the copper looks red, it's not a 40%
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Moderator
United States
95018 Posts |
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Pillar of the Community
Canada
6244 Posts |
The Sigma will not show you accurate because it is not design for the test you need. This it is design for bars, bullions and not for clad or plated coins. Then the results because it is EMF is just the interpretation of the operator.
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Pillar of the Community
 United States
6464 Posts |
According to a Coin World article on an ANACS certified 40% silver 1971 Kennedy half dollar: Quote:
ANACS senior numismatist Michael Fahey said graders relied on the 40 percent silver 1971-D coin's specific gravity in making the silver-copper clad determination.
The coin's specific gravity is 9.5, close to the standard 9.53 for silver-copper clad, with a weight of 11.44 grams, within tolerance of the U.S. Mint standard 11.5-gram planchet.
Specific gravity for copper-nickel clad is 8.92 and a coin's weight is 11.34 grams. So apparently the ANACS expert grader chose not to do a direct metal test, and instead did a specific gravity test. That probably isn't too tough to accomplish, probably any high school chemistry teacher would be able to precisely measure displacement. Archimedes for the win! |
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Moderator
United States
187702 Posts |
Looking a the edge of this one, I see evidence of plating.  |
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Replies: 20 / Views: 2,358 |
Posted 07/26/2023 10:39 am
