A great link from the U.S. Mint. I like the videos that illustrate each step. https://www.usmint.gov/news/inside-the-mint/how-coins-are-made-coin-production-terminology
Wish I could give you more likes @JeffC I strongly recommend any collectors interested in learning about errors/varieties book mark that site. Understanding the minting and die making process is the key to determining if your "unusual" coin is a truly and error or just PMD.
Thanks. I think that the senior experts here would find it a bit boring, but decided to post it because there are those (like me) who will see this for the first time. My one disappointment was that there was no videos for Step 6 (Striking). I wanted to see - in slow motion - how the coins are struck and what happens when there's edge lettering. Wish they had included that - even if it's CGI, like they did with Upsetting (Step 5) when they showed how the coin moves down the narrowing track.
edge lettering information. That process is actually separate after the coins are minted. ==>https://www.usmint.gov/news/inside-the-mint/behind-the-scenes-denver-san-francisco-mints ==> https://www.coinworld.com/videos/monday-morning-brief-oct-3-2016.html ==> https://presidentialdollarguide.com/presidential-dollar-edge-lettering/