I've posted before about one of my 1776-1976 US Bicentennial coinage errors: http://goccf.com/t/159418
Today, I thought I'd "show-and-tell" about a Bicentennial set I recently added to my collection - a set of reverse clad layer missing coins.
In 1965, the US changed the planchets it used for its traditional circulating silver coinage from solid silver (90% silver/10% copper) to one comprised of three layers. For the dime and quarter, the new "sandwich" planchets were made of a pure copper core in between layers of 75% copper/25% nickel. The 1965-70 half-dollar planchet consisted of outer layers of 80% silver/20% copper and an inner core of 20.9% silver/79.1% copper - it produced a 40% silver (by weight) planchet. From 1971, the circulating half-dollar planchet was the same composition as that used for the circulating dime and quarter.Read More: Commems Collection
The use of clad planchets created an entirely new area for error coin collectors to pursue. Namely, "sandwich" coins that were struck on planchets that were missing one (or both) of the copper-nickel layers that surrounded the copper core. Coins struck on these "missing clad layer" planchets have their design pressed into the copper core and result in a "red" coin rather than one with the expected silvery appearance. Missing layer coins are available for all of the clad denominations and can be found with either the obverse or reverse struck on the side with the missing layer; they can also be found for most (if not all) years since 1965. On rare occasions, coins can be found that were struck only on the inner core (i.e., with both clad layers missing!).
For quite some time, I've thought about assembling a set of Bicentennial reverse clad layer missing coins, I thought they would present an interesting contrast to the standard coins. As they are reasonably scarce, however, they do not come on the market with great frequency. Recently, I had the opportunity to acquire a nice mint state set and so decided to take the plunge.
Here they are!