| Author |
 Replies: 9 / Views: 252 |
|
|
Valued Member
United States
385 Posts |
Can a copper nickel coin weigh more than a .925 silver coin of the same diameter, width and even design?
On some 80s New Zealand coins Krause is showing 27.22 for silver proofs and 28.28 CuNi business strikes.
|
 Newly listed items on eBay by Lancek. View all Lancek's items on eBay.
 |
|
Pillar of the Community
United States
4590 Posts |
Huh. I would think that the silver is denser than copper.
I copy and pasted this from a website:
A cubic foot of copper would weigh 559 lb. Silver is even denser than copper, at 655 lb for a cubic foot. Gold is really heavy at 1206 lb for a cubic foot.
|
|
Pillar of the Community
United States
5278 Posts |
You would need accurate measurements of the thickness of each coin - be careful, many time this dimension is rounded off.
It is possible for a CuNi coin that is thicker than a same-diameter silver coin to weigh more.
Collecting history one coin or medal at a time! (c) commems. All rights reserved.
|
|
Bedrock of the Community
Australia
18141 Posts |
The copper nickel and silver coins could be exactly of the same weight and diameter, as per Mint specifications.
.925 Silver has a higher density than copper nickel by about 15%, and thus the difference in specification will be found in the thickness of the coins by about 15%, the CN examples being thicker.
The CN coins are also usually identified by having finer edge milling.
Careful measurement for thickness with an accurate micrometer screw gauge becomes essential to help with investigations. You may need the assistance of a engineering machine person if you don't have one.
Problems arise in the investigations when there is a difference in the specifications between the silver and CN coins for weight. This problem can be overcome by careful application of arithmetic for density volume weight and diameter, and the use of the micrometer screw gauge.
|
|
Bedrock of the Community
United States
17230 Posts |
Quote:
Careful measurement for thickness with an accurate micrometer screw gauge becomes essential to help with investigations. But to be meaningful you would need to take a measurement at a couple dozen or more places all over the coin (and not the edge) to determine an average thickness. Trying to measure the "thickness" of a struck coin is an exercise in futility. What you need is to be able to measure the planchet or preferably the blank. Striking pressures can make the thickness of the coin vary. For a copper nickel blank to weight the same as a sterling silver one of the same diameter it would have to be 10% thicker.
Gary Schmidt
Edited by Conder101
02/23/2021 6:41 pm
|
|
Bedrock of the Community
Australia
18141 Posts |
If you need to take thickness measurements on opposing points in the fields of a coin, a specialized type of micrometer screw gauge is needed: one with domed tips on the touch points.
Such instruments are available - usually to be found in materials labs or machine shops.
|
|
Pillar of the Community
United States
4390 Posts |
Yes.
If either the thickness or the relief are different.
No if struck in exactly the same dies.
It is not clear from the original post which of these (if either) applies.
Edited by tdziemia
02/23/2021 8:41 pm
|
|
Valued Member
United States
472 Posts |
"Tell me and I forget. Teach me and I remember. Involve me and I learn." -Benjamin Franklin
|
|
Pillar of the Community
United States
4390 Posts |
Interesting that you were paying enough attention to notice that. I doubt I would have.
Pretty sure the cupronickel coin must be at least 14% thicker.
|
|
Bedrock of the Community
United States
17230 Posts |
Which would mean for a planchet 2.5 mm thick, the copper nickel planchet would have to be 2.9 mm thick.
Gary Schmidt
|
| |
Replies: 9 / Views: 252 |
|
Posted 02/22/2021 2:29 pm
1996 AMERICAN SILVER EAGLE ASE MINT ERROR MS 69 ANACS KEY YEAR!
1846 NETHERLANDS SILVER GULDEN WITH RARER FLEUR DE LIS PRIVY MARK
1892 E GERMANY EMPIRE 20 PFENNIG KM 13 RARER MINT MARK
1887 E GERMANY EMPIRE 20 PFENNIG KM 91
1971 S MS67 EISENHOWER IKE SILVER DOLLAR ANACS RARE HIGH GRADE FOR FIST YEAR
