Hey folks, I have some questions about mint marks and the process of putting them on a coin. When in the minting process are they put on? I ask because I am wondering how it is possible to have two different mint marks on a coin. For example, a D over S...etc Thank you for the help. -greg
Until the late 1980's, mint marks were hand punched into individual dies, if they were wrong, they were punched again over the earlier mark. Today, they are machined into the master die, making it impossible to have doubled or over mint marks.
G, All of the mintmarks were punched into the dies at Philadelphia before they were shipped to the branch mints which made it possible for a diesinker to mistakenly use the wrong letter punch. Chris
Well yes, but there were exceptions. For example, a shipment of dies is sent to San Francisco for use. All of the dies are already marked with an S. But then the SF mint stops minting those coins and they have dies left over. But now Denver, for whatever reason, needs to mint more of those same coins - but they are out of dies. So Denver calls SF and gets them to ship the excess SF dies (already marked with an S) to Denver. The Denver mint then uses a punch and places a D mint mark over that S mint mark. And thus you have a D over S coin. And it didn't happen in Philly.
Except Denver doesn't have a D mintmark punch. Overmintmarks were made at the Philadelphia mint and the dies were typically shipped already hardened so punching in a D in Denver would be very difficult to impossible. More likely Philadelphia had a supply of unhardened S mint dies on hand and when they were determined to be superfluous they were remarked with the D and shipped to Denver.
