The Great Coin Weight Experiment

SilverEagles92

I conducted my own little experiment with some of my PCGS slabbed Half Eagles.

Hypothesis: The more worn a coin is, the less it will weigh (versus its MS counterpart).

The Experiment: First, I gathered 3 different PCGS-slabbed Half Eagles. I then proceeded to put them on my digital scale (accurate to 0.1g) and weighed them. I used one VF35 Half Eagle, one AU55 Half Eagle, and a FR02 Half Eagle. The results were surprising.

Results:
AU55: 39.8g
VF35: 39.4g
FR02: 38.8g

Now, a note on the FR02 coin. This coin was a Classic Head Half Eagle, rather than a Liberty Head half eagle like the other two coins were. There is 0.001g of a difference in weight between the two (in MS condition), but there is also a 0.9mm difference in diamater, accounting for less plastic weight in the PCGS slab. I am also willing to accept that there will be inconsistencies within the PCGS slabs, errors in the weighing by the scale, yadda yadda yadda. Still, I would say that the coin actually has lost about half a gram of weight since it was in Mint State condition.

I would also say that from MS to VF, this particular half eagle lost 0.3g or so (again, inconsistencies in the plastic); and since AU was our control, I cannot speculate on the weight of that particular coin.

Can anyone prove or disprove my hypothesis? Has anyone else conducted a similar experiment to this one? What were the results?

I await your feedback!

ricko

JMHO... the experiment needs to be conducted without slabs and all the identical type coins. This is interesting, but leaves too many factors unaccounted for.... Cheers, RickO

Nysoto

Yes, get rid of the slabs. I have weighed about 15 early halves, and am planning to do a full analysis. There is considerable variance for the same grade, even beyond the tolerance defined by the US Mint, as the filing of planchets was not that accurate. For fun, I also weighed statehood quarters, and there was variance of +-.03 gram (if I remember right), I am not sure what the spec is for these.

It would be interesting to see the range of weight for other series within the same grade, this would have to be factored in to any grade/weight estimates that would give a range, rather than a specific amount, for a grade.

cladking

There is a lot of correlation between preservation and weight but
it sould be remembered that strike characteristic play a large role in
both the rate at which the designs are worn but the initial state of
these designs. There is also a lot of variability between planchets
in their weights and annealings. There is a little variability in planchet
size because the blanking dies wear which leaves varying amounts
of metal at the edges of the upset planchets.

Coins with strong rims wear better than those with poor or weakly
defined rims. Designs that are well struck up remain visible much long-
er than designs which are weak or even non-existent. There is also
some variability in wear itself. Some coins recieve only the normal
rubbing sort of wear for most or all of their lives while others might
lose two or three grades almost all at once in an "event". Coins can
get caught up in a poker game or in machinery.

Weight does get too little notice in coin grading but even coins with
close tolerances ($20 gold) can't be graded on weight alone. Strik-
ing characteristics should get a great deal more attention on all but
the most heavily worn coins.