One of the most common questions I get asked is about two-headed coins. Someone finds the coin in circulation, so they're sure it has to be genuine! They look at the edge, and don't see a seam, indicating that the coin was two "heads" halves that have been joined together. If the two-headed coin is a fake, it has to have this seam, right?
Well, no... In fact, most two-headed coins are very cleverly put together because they are intended to be examined by spectators during a magician's show or during some other display of clever coin manipulation (such as tossing a coin to see who buys the drinks.) One thing all two-headed U.S. coins have in common is that they did not come from the U.S. Mint this way!
Learn about how to detect the joined halves of two-headed coins, so you can authenticate these cleverly deceptive marvels for yourself.

Comments
I have seen this same question asked all over the internet. It’s usually right behind the rant about how there’s no such thing as a U.S. penny.
I do have a question about something you wrote in the article that you linked to. You wrote, “The shaft of the dies are made to be a certain size and shape, so that they will only fit into the coin presses a certain way.” The explanation of round and square was great. My question is, do you know where I might find some photos of this? I have never noticed a gallery on the U.S. mint’s website. Unless it’s a national security threat for us to see what the machines look like!
I found pics of dies just by punching in “pictures of US coin dies” There were quite a few US Dies there.
Susan was 100 percent right regarding overgrading by some companies. I bought an 1880-0 Morgan on EBAY advertised as BU+++MS 65. I paid $400.00 and purchased 4 other coins from the same dealer. I took 1880 to an expert who advised the coin had been polished and valued at about $25.00. The seller immediately took all coins back (probably to keep a “perfect” rating with EBAY. No more EBAY for me. thanks Susan