What variation in cents should I anticipate?

[coppernickel]

What variation in cents should I anticipate?

I have recently started weighing and saving 1982 cents. What variation in cents should I anticipate?

On my scale I am getting variations of 2.9-3.1 grams and 2.3-2.6 grams.

Looking at the reported exacting standards of the mint quality controls this makes me a bit nervous.

If finding this much variation in cents what should be expected when checking other coins?

[Recyclersteve]

The ones which are heavier are copper cents and the ones which are lighter are zinc. They transitioned from largely copper to largely zinc during the year 1982 which is why you are getting such a variation in weights.

Many on this site are saving the coppers- probably very few are saving the zincs, unless there is some kind of error/variety that year that makes them worth saving.

[68Camaro]

First, if you care about the first decimal place (x.x) then you need a scale that will read to (and is reasonably accurate to) the next decimal place (x.xx). Doesn't sound like you have a scale that reads to hundredths of grams, which is what you would need to resolve some of this.

Second, lower your expectations on the mint's "exacting standards". For circulating coin they weren't that exacting on an individual basis. +/-4 or 5 percent in the extreme isn't ridiculous for some coin (I've noted those levels in thousands of individual silver coin weighings, and kept a couple of the real odd-ball low and high outliers off to the side). I've not weighed a lot of cents, but I wouldn't expect anything different. And that doesn't include the bias to the low side for coin that was heavily circulated and worn.

What you're seeing are two groups for the two types of cents in 82: the group of 95% copper cents, which had nominal weight of 3.1 grams, and the group of copper plated zinc cents, which had nominal weight of 2.5 grams.

[coppernickel]

The coppers are interesting to me that most are just under weight, 2.9-3.1 grams, but the Zinc appear to have more variation being in the 2.3-2.6 grams range.

My presumption was the scale was accurate, but it appears more decimal places and accuracy are needed.

I am worried this will make verifying silver coins more difficult, is the mint more accurate with collectible coins?

[68Camaro]

Circulating silver is what I've based most of my conclusions on. From that I've concluded you can't distinguish an individual counterfeit by weight alone, unless they are truly awful counterfeits (and some are that). If they can get within 5% of nominal they are within the bounds of error. Granted, most real coins are within +/- 2%. Ultimately the best defense these days is a PMV (precious metals verifier), which measures electrical conductivity.

In contrast the bullion coins (e.g., ASEs) are made from very precise planchets; the variation on those individual coins is 2 orders of magnitude less than the circulating coin.

[TwoAndAHalfCents]

Sounds like the accuracy of the scale is the issue. I weigh 1982 cents all the time on my gram scale which has a reading to two decimal places. I sort the copper from zinc by the ring test and then weigh the separated coins in stacks of ten. A stack of ten copper cents will come in at 31g +/- 0.05 on my scale and a stack of ten zinc cents weighs in at 25g with a slightly wider tolerance.

[68Camaro]

Sounds like the accuracy of the scale is the issue. I weigh 1982 cents all the time on my gram scale which has a reading to two decimal places. I sort the copper from zinc by the ring test and then weigh the separated coins in stacks of ten. A stack of ten copper cents will come in at 31g +/- 0.05 on my scale and a stack of ten zinc cents weighs in at 25g with a slightly wider tolerance.

Scale is a big part of it, but for the OP your results would be more meaningful if you reported the range of variation of individual cents rather than the sample average; by weighing 10 at a time you are both shifting the weight of the sample into the most accurate range of the scale, as well as averaging out the variation of the individual cents. The average of a population is indeed 3.1 and 2.5 for each type.

[TwoAndAHalfCents]

Yes, my technique is averaging out the variation of individual cents.

[coppernickel]

Interesting, I hadn't thought about weighing more than one.

Appreciate the help.

[Recyclersteve]

I always weigh them two at a time. If I see a weight of, say, 5.2 grams, I know it is two zincs. If it is 6.2 grams, I know it is two coppers. That saves me a lot of time versus weighing them one at a time. I also use a Ryedale when I want a machine aided sort.