Pre-1982 Copper Pennies

An interesting article was recent posted to the Steem blockchain by @david777111 titled: When One Penny Can Be Worth Almost Two Pennies. ^[2]


Of course, I wanted to read more and find out what change was made in 1982 to the metallurgical composition of the penny. A quick search led me to the CoinTalk.com website and the article A Guide to 1982 Lincoln Cent Identification. That article states:

Before 1982, the Lincoln Cent was made on a 95% copper planchet. Due to the cost of materials, a planchet change was needed in the 1980s. It was decided that a change to a 99.2% zinc planchet plated with copper was the economical alternative. So, that change was made in 1982. Unfortunately for collectors, the change was made in the middle of 1982 resulting in some cents comprised of 95% copper and others 99% zinc with no obvious way to tell them apart.^[1]

So, I learned a new word today: planchet, "is a round metal disk that is ready to be struck as a coin." ^[3]

Since the planchet-swap happened mid-year, any coin stamped "1982" could either be predominately copper or predominately zinc. The author of the article cites the difference in weight of the copper planchet versus the zinc planchet as an easy way to determine which was used when the coin was minted. The copper planchet weighs 3.11 grams, and the zinc planchet weighs 2.50 grams. In the absence of a fancy scale, the author constructed a simple method to weigh the coins using a popsicle stick and a soda straw, making a see-saw/teeter-totter gizmo. Having one coin minted much-earlier than 1982 and one much-later, he is able to easily determine the planchet composition of any 1982 penny! I give him kudos for ingenuity!