U.S. Coins

Flipover Double Strike

Published December 1, 2023 | 4 min read

By David McCarthy

In the December issue of The Numismatist (p. 17), I wrote a little about Henry Hilgard. He was one of my favorite people to talk coins with for many years. Henry wasn’t particularly interested in what something would grade or how much it was worth. Instead, he wanted to understand completely whatever it was that he was looking at. Early errors were his area of expertise. I’m not exaggerating when I say that he could spend hours reconstructing just how (or why) something like a multiply struck piece of Massachusetts silver came to be. Now and then, I come across a coin I know he’d love. It reminds me how much I miss our talks.

One of these coins popped up at a recent show. A good friend of mine stopped by my table with a typically crude mid-19th-century Vietnamese gold coin. Immediately, I noticed something about it that I knew Henry would have loved. Both sides showed bold, identifiable undertype. After looking at it with a 10x loupe, it was apparent that the piece was a flipover double strike. This popular error generally occurs when a coin is struck, fails to be ejected from the coining chamber, flips over, and is struck again.

This explanation is something of an oversimplification. I’m pretty sure Henry and I must have discussed it at some point. The description generally offered up for these errors proceeds from a modern understanding of the minting process. Today, the mint aims to produce and issue lots of essentially perfect coins. However, an examination of early flipover double-strike errors demonstrates that the early coining facility may not have been as concerned with perfection as modern mints are.

I suppose it’s likely that mint workers would have corrected coins as they were struck.

I’d estimate that around 75 percent of the early flipover double strikes I’ve seen show an error on the first strike with a perfectly centered second strike. Generally, the first-strike error is off-center. However, in some instances, other errors (like brockages) show up as undertype. This suggests that, at least some of the time, a mint employee caught error coins and ran them back through the press to “correct” them.

All of this was on my mind as I looked at the Vietnamese coin. After determining it was a flipover double strike, I realized that although the undertype was the correct denomination and type, the characters didn’t quite match. After studying it for a while, it became apparent that the first and second strikes on this unusual piece were from two different pairs of dies. Why this was done is a mystery to me; no error was apparent under the second strike. My best guess is that a previously struck coin somehow got mixed in with a group of blank planchets.

Thinking about this odd bird made me wonder whether any flipover double-struck errors in the U.S. series were struck from two different die pairs. Over the past month, I’ve looked at old auctions in my free time but have yet to find an example. I suppose it’s likely that mint workers would have corrected coins as they were struck. If Henry were around, he’d have some ideas. And even if we couldn’t get to the bottom of the mystery, we’d end up having a great talk.

A version of this article appears in the January 2024 issue of The Numismatist (money.org).