When a Mint Employee's Mallet Struck Twice

Before 1990, the U.S. Mint added mint marks to working dies by hand. A Mint employee would position a small steel punch bearing the appropriate letter (D, S, O, CC, W) over the designated spot on the die and strike it with a mallet. This manual process was inherently imprecise — and that imprecision created Repunched Mint Marks (RPMs).

RPMs occurred when the first punch was off-position, didn't sink deep enough, or the die shifted between strikes. The result: traces of both the original and repositioned mint mark, creating visible doubling, tilting, or displacement.

The 1990 Cutoff

In 1990, the Mint began adding mint marks to the master die rather than individual working dies. This meant all working dies had identical mint mark placement, effectively ending new RPM production. RPMs on 1990+ coins are extremely rare. The prime collecting era is 1909 through 1989.

Prime Hunting Ground: Jefferson Nickels

The Jefferson nickel series has hundreds of documented RPM varieties, many affordable. The mint mark was on the reverse (1938-1964) and then moved to the obverse (1968-present), so RPMs appear in both locations. Cherry-picking through bank rolls of pre-1990 nickels remains productive.

What to Look For

North/South RPM — Secondary mint mark above or below the primary
East/West RPM — Secondary to the left or right
Tilted RPM — Secondary at an angle to the primary
Over Mint Mark (OMM) — A different letter punched over the original (e.g., D/S)

Discussion

Do you collect RPMs? What series do you focus on?
Have you cherry-picked an RPM from a dealer's inventory or a bank roll?
What's the most dramatic repunching you've seen — N/S, E/W, or tilted?
Do you use Wexler's doubleddie.com or CONECA's VarietyVista for attribution?

Hub & Punch Errors

Repunched Mint Marks: Hand-Punched History