Here's another coin from my "Something's Missing" collection of US Bicentennial coinage - this one is a low net pressure strike that yields a coin with most of its design details missing - it is often called a Die Adjustment strike (as seen on its PCGS
Weak strikes such as the one seen on this Kennedy half dollar
can be caused when a normally-functioning press is not calibrated to strike a planchet with the proper/needed pressure (a potential scenario during setup) or the coinage dies do not come close enough to the planchet to generate a fully-struck coin.
Mike Diamond, and other error coin experts, suggests that the relative availability of this type of error coin strongly suggests that few of those found in the marketplace are truly Die Adjustment strikes. He argues that such coins occur during a controlled process (e.g., press setup), are produced in limited number and are not part of the normal coining operation such that they could easily escape from the Mint. Instead, he believes an ad hoc equipment malfunction that prevents the dies from coming close enough together to properly strike the coin produces the bulk of these errors.
A great discussion of these error coins by Mike can be found here: Weak (Low Pressure) Strikes
I tend to agree with Mike regarding the cause of most of these "Die Adjustment" coins. The numbers available seem to exceed what would expected if they were all from press operators making adjustments to the dies. It seems far more likely that the majority of coins in the marketplace result from equipment malfunctions that prevent the dies from coming close enough together to fully and properly strike the coin in question. A good number of such coins could be produced before the issue is detected and many could escape detection mixed in among the properly-struck coins.
Turning attention to my coin...I don't know what the PCGS
grader was looking at when he/she graded my coin a MS-60, it's very clearly a MS-61+ example!
Kidding aside, I do think the coin was struck slightly off-center - check out how part of the "L" in "LIBERTY" is missing and how close "IN" from "IN GOD WE TRUST" is to the rim of the coin.
Here are links to a couple of other errors on Bicentennial coinage that I have:
- 1976 Bicentennial Ike Error
- 1986 Bicentennial Clad Layer Missing Errors