Varieties
Repunched Mintmarks (RPM): How to Identify and Attribute Them
Repunched mintmarks are one of the most approachable die varieties to hunt. They sit on a tiny, predictable spot on the coin, many are listed in specialist references, and once you’ve seen a real one under magnification you won’t forget it. The challenge is telling a true repunching from strike doubling, die wear, and a mintmark that was simply damaged in circulation.
Quick answer
- An RPM happens when a mintmark punch was struck into a working die more than once and the impressions didn’t line up perfectly.
- An over mintmark (OMM) is a different letter punched over another, such as a D over an S.
- True RPMs show a distinct secondary impression of the letter, often with its own serifs or curves, offset in a consistent direction.
- Machine doubling on a mintmark looks like a flat shelf on one side and usually matches doubling on nearby date digits.
- Describe the direction of the secondary mintmark (north, south, east, west, or combinations) and compare to published listings before claiming an attribution.
How repunched mintmarks happened
For much of U.S. coinage history, the mintmark was not part of the hub. Each working die destined for a branch mint had its mintmark added by hand, with a punch and a hammer. Sometimes the first blow was light, tilted, or out of position, so the worker struck the punch again. If the second impression didn’t sit exactly over the first, the die now carried two overlapping letters, and every coin struck by that die shows both.
Because the doubling is in the die, an RPM is a die variety, not a strike error. That’s why it repeats on every coin from that die and why specialists can catalog it. (If the variety/error distinction is new to you, start with our post on doubled die identification, which uses the same logic.)
On older coinage, the same hand-punching process was used for date digits, which is why repunched dates and over-dates exist too. Once the Mint moved mintmarks into an earlier stage of die making, new RPMs essentially stopped appearing on circulating coins.
RPM, OMM and their relatives
| Type | What happened | What you see |
|---|---|---|
| Repunched mintmark (RPM) | Same letter punched two or more times, slightly offset | Two overlapping images of the same letter |
| Over mintmark (OMM) | One mint’s letter punched over another’s (e.g. D over S) | Remnants of a different letter shape under the main one |
| Tilted or rotated mintmark | Single punch, struck at an angle or rotated | One letter, noticeably out of normal alignment |
| Misplaced mintmark | Mintmark punched in the wrong place first, then corrected | Traces of a letter where none belongs |
| Machine-doubled mintmark | Strike doubling, not die doubling | Flat shelf on one side of the letter, usually also on nearby digits |
A well-known over mintmark is the 1938-D/S Buffalo nickel, where traces of an S are visible beneath the D. It’s a useful study example because it shows how a different letter’s curves peek out from under the main mintmark.
How to tell a true RPM from machine doubling
This is the key skill. Machine doubling (also called strike doubling or mechanical doubling) happens during the strike when a die bounces or shifts slightly, smearing the design sideways. It’s very common and doesn’t create a variety. On a mintmark it can mimic an RPM at a glance.
- Shape of the secondary image. A true RPM shows a second impression with its own curves, serifs or corners. Machine doubling shows a flat, squared-off shelf, as if the edge of the letter was pushed sideways and flattened.
- Height. The secondary RPM image is usually rounded and at or near the same relief character as the main letter. Machine doubling sits lower and flat.
- Neighbouring features. Machine doubling usually affects nearby date digits and lettering in the same direction. An RPM affects only the mintmark.
- Direction. RPM secondaries can be offset in any direction, including inside the main letter. Machine doubling tends to appear on the same side of all affected elements.
Our posts on machine doubling vs doubled dies and what to compare show the same principle applied to whole designs.
Other look-alikes
Die deterioration
Worn dies produce blurry, ghosted outlines around design elements, including mintmarks. The effect looks like a soft halo rather than a second, defined letter. Late-die-state coins also tend to show grainy fields and flow lines. See die deterioration vs true doubling.
Filled or damaged mintmark punches
Debris in the die or a chipped punch can leave odd shapes in or around the letter. These don’t produce a second, offset image of the whole letter.
Post-mint damage
A nick or scratch near the mintmark can look like an extra stroke. Check whether it is recessed (likely damage) or raised (consistent with die features). Damage often pushes metal and disturbs the surrounding luster.
Describing direction: the compass method
RPMs are described by where the secondary image sits relative to the main letter, using compass directions with the coin held in its normal upright orientation. North is toward the top of the coin, east to the right, and so on.
- “D/D North”: the secondary D shows above the main D.
- “S/S South”: the secondary S peeks out below.
- “D/D Northwest”, “S/S East” and so on for diagonal or side offsets.
- “Rotated” when the secondary is turned rather than shifted.
Using this vocabulary in your notes and when asking for opinions makes it much easier for specialists to match your coin against their listings.
Step-by-step: checking a mintmark
- Confirm the basics. Date, mint and design type. Make sure the coin should have a mintmark at all; many Philadelphia coins don’t (here’s why).
- Magnify to around 15x–30x with a single low-angle light. A stereo microscope makes this much easier than a loupe.
- Rotate the coin through 360°. Secondary images often appear only from one lighting direction.
- Write what you see: shape, direction, raised or flat, whether nearby digits show doubling. (See observations before attribution.)
- Check published listings for that date and mint. Specialist references list RPMs with photos and die markers, often numbered.
- Match die markers, not just the mintmark. Different dies can have similar RPMs; small die chips, cracks or polish lines tell them apart.
- Photograph and ask specialists if you can’t match a listing. Our microscope settings guide helps you avoid photos that invent detail.
Where RPMs show up
RPMs are found on many older series that carried mintmarks, and Lincoln cents are a popular place to learn because they are plentiful, inexpensive, and well documented in specialist listings. Older nickels, dimes and other denominations from branch mints also have numerous listed RPMs. Rather than chase any particular date because a headline mentioned it, pick a series you enjoy and work through it systematically with a reference in hand.
When you’re ready to see certified examples, searching by attribution term gives the best results:
Attribution and value research
Minor RPMs are frequently left raw, while major listed ones are often certified with the variety on the label. Grading services name an RPM on the label only if it is on their recognized list; specialist attributers catalog many more. Our guide to grading and certification explains the options.
When researching value, compare the same listed RPM in similar grade. An unlisted or minor RPM on the same date is a different coin in market terms. Always use sold results, not asking prices:
See sold certified RPM coins on eBay
Storage once you find one
Keep an attributed raw RPM in an inert holder with a note card listing the date, mint, RPM direction, any attribution number you matched, and where you found it. If you later submit it, that record makes the submission form simple and gives you a reference if the result differs from what you expected.
Browse archival coin flips on Amazon
Frequently asked questions
Are repunched mintmarks rare?
Many RPMs are common enough to be found by patient searchers, while a few are major listed varieties. Because they were made die by die, there are a great many minor RPMs. Rarity and collector interest vary widely, so research each attribution separately rather than assuming any RPM is valuable.
Why don’t I find RPMs on recent coins?
Repunched mintmarks come from the era when mintmarks were hand-punched into each working die. Once the Mint moved the mintmark into an earlier stage of the die-making process, the opportunity for a hand-punched mintmark to be doubled largely disappeared. Focus RPM searches on older coinage.
What does RPM #1 mean?
Specialist catalogs number the RPM dies they have listed for a given date and mint, for example RPM #1, RPM #2 and so on. The number refers to a specific die with specific diagnostics, not to a ranking of importance.
Can an RPM be faked?
Altered mintmarks are a known problem in general numismatics, especially where adding or changing a mintmark would mimic a scarcer coin. Look for tooling marks, disturbed surfaces around the letter, or a letter that doesn’t match the punch style. For anything significant, get professional authentication.
The bottom line
A real repunched mintmark has a story you can see: a second, distinct impression of the same letter, offset in a consistent direction, with the design and surface around it undisturbed. Machine doubling, die wear and damage tell different stories. Learn to describe what you see by direction and shape, match it to a listing’s diagnostics, and ask specialists before assuming you’ve found something new.
RPMs are a great way to train your eye for every other die variety, because the area is small and the evidence is concentrated.