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 Replies: 15 / Views: 2,076 |
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Pillar of the Community
United States
1215 Posts |
Hey, I was wondering if there is any kind of system by grading coins according to a very accurate scale (down to .1 milligram)
If not, I think it would be interesting if someone were to take samples of a lot of coins of each grade, as done by a professional grading service and doing statistical analysis to see how well the numerical (1-70) grade correlates to the weight of the coin in some kind of relation, assuming same metal of coin and no foreign substance on the coin.
Then grading would be a lot easier.
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Pillar of the Community
Canada
5417 Posts |
0.1 gram isn't even close enough to an accurate scale. Coin weighing needs 0.01g accuracy. To grade by weight would be a very "iffy" idea and would need a very accurate scale, perhaps 0.001g.
Edited by zxcccxz
07/14/2014 6:50 pm
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Moderator
 United States
56855 Posts |
I don't see that working.Lets say you have a coin graded MS65 in the traditional manner and it weights 3.11g.Take that coin and hammer and bang away.Now the coin is all messed up and still weights 3.11g but would grade damaged,not even a G4. John1  |
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Pillar of the Community
United States
5825 Posts |
The Mint has a tolerance range for coins.
I forget what it is but it's much larger than 1 mg and may be as large as 0.2-0.3 gms.
(All my resources are currently packed away.)
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Pillar of the Community
 United States
1215 Posts |
Zxccc, I don't get what you are meaning. 0.1 mg is more accurate than the measures you mentioned.
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Pillar of the Community
United States
5854 Posts |
It would be great if we could grade coins by weight as that would eliminate a some of the subjectivity. The problem is freshly minted coins don't all weigh the same so it would be possible for a coin that is in a lower grade to weigh the same as another in a higher grade. Even given the variability in weight, the idea could still have useful benefit if coins in lower grades were significantly lighter than newly minted coins but in reality coins that are underweight by about 5% are going to be worn flat.
Edited by D0ubl3Eagle
07/14/2014 6:48 pm
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Pillar of the Community
Canada
5417 Posts |
Quote:
Zxccc, I don't get what you are meaning. 0.1 mg is more accurate than the measures you mentioned. It was a typo. I meant grams. |
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Pillar of the Community
United States
1512 Posts |
I think the OP was trying to make a suggestion for a study to be conducted that would list the mass and numerical grades of similar coins and see if there is a correlation between the two, thereby providing another tool to utilize for grading our beloved coins!
For instance if a specific coin's mass was rated at 3.11g and if 95% of all MS64 or greater coins fell within a defined tolerance (say +/- .02g), but only 15% of AG-AU coins fell within the tolerance range then that could possibly help us in making a decision between two coins that appear similar visually.
I don't know for sure, so please, OP, correct me if I am wrong. Interesting idea though.
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Pillar of the Community
United States
1215 Posts |
mattt, I was alluding to that, yes. I would like to see such a study, if it's not yet done. Would make grading easier. One thing about the tolerance issue that people are mentioning: What if the tolerance is only referring to 0.0001% of all coins? Then, they would be consistent. Then again, I don't have two ms70 coins that are not slabbed to find out, though I have a 0.00001 (.1mg) precision scale.
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Pillar of the Community
Canada
519 Posts |
Differences in the starting weight of each coin are quite significant even with modern issued coins. Your scale would be 0.0001g.
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Valued Member
United States
139 Posts |
Hmm. One would think that it wouldn't be difficult for a coin grading service to offer a "stat" sheet on your submitted coin. For a small extra fee, you could have all the precise measurements for that coin, possibly even how it varies from the "standard". Somebody make that happen!
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Valued Member
United States
337 Posts |
So, how much oip and dirt is equivalent to how much metal? Therein lies the problem. And adding a light film would be the new way f altering coins.
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Bedrock of the Community
United States
12437 Posts |
As has already been stated, planchet tolerance renders such an endeavour largely meaningless. For small cents, the tolerance is +/- 2 grains or 0.13 grams so a normal 1864-1982 bronze cent can weigh between 2.98g and 3.24g. Gold coins have the lowest tolerance(0.25-0.5gr depending on denomination) while clad Ikes have the highest(15.2gr).
It is also worth noting that any scale that both purports to measure down to 0.1 milligrams and be accurate in that measurement would qualify as an analytical balance, the one in my research lab retails for ~$2000 so it is certainly not something the average collector can afford.
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Pillar of the Community
United States
1277 Posts |
I don't think it makes sense at all for near uncirculated coins as virtually no metal is lost. It the planchet size were consistent, which it is not, it would be a good way to determine how much metal wore away, which could correlate to the grade for more heavily worn coins.
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Pillar of the Community
United States
1277 Posts |
Of course this would have to be done for each denomination and series.
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Bedrock of the Community
Australia
21788 Posts |
It is not even remotely possible to grade an MS60 or above coin, using weight, because coins of MS60 and above have no wear, and therefore no loss in weight.
It is in coins MS60 to 65 where there is the steepest rise in values.
For the lowest grades where there IS a loss in weight, is is obviously easy to grade by visual inspection. Most coin catalog type of books have a picture guide in them for the benefit of the novice grader.
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Replies: 15 / Views: 2,076 |
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Posted 07/14/2014 6:17 pm
