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 Replies: 9 / Views: 17,787 |
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New Member
United States
2 Posts |
I recently ordered 5 silver American Eagles of various dates from 1986 through 2007. They all look fine (except one looked a little dull, but it got shinier when polished it a little). But I also ordered a digital scale and weighed them all. The official weight is 31.103 grams. These weighted between 30.86 and 31.16 grams, for a variance from high to low of .3 grams, or about 1%. Now, my scale might be off by a little, so it may be that these are all over 31.103 grams, but there is definitely a variance in weight. Is this normal? I've searched far and wide for an answer here but I've heard it all. Some people say no variance is possible in real coins, which I find very unlikely. Another says that he has some Maple Leafs and they have up to a 1% variance too. What I really would like to hear is from someone who has weighed "known good" silver American Eagles and can cite the variance they found. Thanks in advance!
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Bedrock of the Community
Australia
21788 Posts |
All mints, in the specification for each type of coin they make have what is known as a 'Remedy Allowance' This is the range of weight between the upper and lower weight, whereby the coin is legal. Coins outside this weight range should never be issued, and should be remelted.
With a bit of digging, you should be able to obtain this information from the U.S.Mint. I'll let you do the digging, and have fun learning more about numismatics.
Read about the Trial of the Pyx in regard to British coins. This is a tradition steeped in British Coinage history. There is an annual ceremony that go back hundreds of years.
Edited by sel_69l
10/02/2010 03:52 am
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Bedrock of the Community
United States
10982 Posts |
31.103g is nominal weight for a ASE as you noted. Very few in home scales are accurate at 0.01 of a gram, so just round to a tenth. On your coin that weighs 30.86g, we'll call it 30.9g with 31.1g being spec nominal. I get 0.6% under weight with my calculator. Is the piece worn at all? A pocket piece perhaps? Losing 0.6% weight could easily happen with a little mis-handling or carrying it around in your pocket. Now if it looks BU, I'd re-weigh it on a calibrated scale. There are a hundred million ASEs floating around and at under $25/each, they're not a big target for counterfeiters. |
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New Member
 United States
2 Posts |
The scale I have has a resolution of .01g. I would also suspect the scale of inaccuracy, but each coin weighs consistently within .01g. That is, if it weighed 30.86g the first time, it will weigh within .01g of that every time I weigh it, so I think the weights are accurate with at least a couple hundredths (except for the possible calibration issue, that is).
Edited by mrdarklight
10/02/2010 04:26 am
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Valued Member
United States
487 Posts |
Question for the people on this thread. What is a good manufacture for a scale and how much should one pay for a scale? Any help would greatly be appreciated.
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Bedrock of the Community
Australia
21788 Posts |
If you only have to weigh a coin accurately once every blue moon, there are two ways I can think of to get the information you seek:
1.) Go to your local pharmacist, he may be able to help you, because he is almost certainly to have an accurate electronic mass balance,
2.) Take your coin to a high school student you can trust. His / her school will have a chemical mass balance in their classroom lab., either a balance beam type or a one pan mass balance.
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Moderator
 United States
56855 Posts |
Quote:
They all look fine (except one looked a little dull, but it got shinier when polished it a little). If these coins are for collecting you should never clean them,if they are simply a form of holding silver then it's o.k. I guess.Just saying,
John1  |
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Valued Member
United States
182 Posts |
Commercially purchased scales are famously inaccurate. Their tolerance, combined with the Mint's own variance, makes you forget about the importance of the thousandth digit. The best thing you can get insofar as accuracy is a good set of weights to zero and span your scale. If you set your digital scale's thousandth digit to 32 grams plus or minus .001, then you know what you are reading is bang-on. If it reads 31.006 after you calibrate it for full scale to be accurate to the thousandth, plus or minus NO ERROR, well, alrighty then: 31.006 equals 31.006.
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Bedrock of the Community
Australia
21788 Posts |
If you are going to use a balance beam mass balance , obviously the best counterbalance is to put a coin of known mass against the coin you are trying to get the mass of. Small counterbalance masses then allow you to more easily determine the mass of the coin you are seeking.
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Bedrock of the Community
United States
17884 Posts |
The mint does has a tolerance range for the silver eagle but I don't know what it is. I would imagine it would be at least as tight as the tolerance was on the old silver dollars or +/-.097 grams. With that tolerance your 30.86 gram coin is low weight and out of tolerance but the 31.16 gram coin is still within tolerance. Just as a rule of thumb call that .097 a +/-.1 grams so if they weigh between 31 grams and 31.2 grams they are within tolerance.
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Replies: 9 / Views: 17,787 |
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Posted 10/02/2010 04:06 am
