With the popularity of coin microscopes, hobbyists are finding all manner of doubled dies, but only one really is valuable. Nevertheless, it is important to identify the three main types so that you can tell whether you have a valuable or face value coin.

Types of doubling covered in this article:

• Hub doubling.
• Machine doubling.
• Die deterioration doubling.

By becoming familiar with the various types of doubling, you not only will be able to increase your knowledge of numismatics but also can help others with their finds.

Hub Doubling

This is the most important kind of doubling, always valuable because most kinds have a decent spread of letters, numbers and devices. You usually do not need a microscope. You can see these with a loupe or naked eye.

This type of doubling is produced by a misaligned hub that engraves the defect directly into the working die, meaning the image will be evident in every coin struck by that working die. That is why the result is called a variety, and not an error.

Here is the most famous doubled die resulting from a misaligned working die:

Some 40,000 of the 1955 DDO were initially struck, with about half of the run caught and destroyed, leaving about 24,000 that made it into circulation.

The key distinction of hub doubling is separated, raised and rounded doubling. Older coins typically have this kind of doubling. In the 1990s, the US Mint introduced what is called a Single Squeeze Process, reducing the number of doubled dies with less of a spread and with doubling occurring more toward the middle of the coin.

If you want to learn more about hub doubling and the minting process, see “How Does Hub Doubling Happen.”

Machine Doubling

Machine doubling occurs when the die moves slightly during the striking process, distinguishing it from hub doubling, which is associated with the working die.

Because machine doubling happens during a strike, its “double” image is flat and shelf-like and not raised enveloping the letter or number like hub doubling,

Compare the two in this comparison image:

Machine doubling, which often requires a microscope to see, is common because the Mint uses extraordinarily high-speed machinery whose vibration often causes the working die to bounce on impact.

Machine doubling typically is caused by a single strike, meaning not all coins of that run will have the same impression, as happens with hub doubling. That is why machine doubling is a mechanical error and not a variety.

It also has no collector value.

Die Deterioration Doubling (DDD)

Like any manufacturing facility, the US Mint uses its equipment on a cost-saving basis, meaning working dies are used until they begin to deteriorate. The striking process is high-speed and powerful. When a die is overused, some of the lettering, numbering or devices begin to erode slightly with metal flows entering the degraded areas.

That’s why die deterioration doubling is common, without value, even though at times this mechanical error looks stretched rather than flat. This is how you distinguish between machine doubling and DDD. (Also, die deterioration appears to be a weak strike.)

When the US Mint started producing copper-plated zinc coins with pressure to produce billions of them each year, mint operators over-extended the lives of working dies, producing millions of DDDs.

There are two other types of doubling, “Split Plate Doubling” and “Reduction Lathe Doubling.” The former also is associated with copper-plated zinc cents with the plating eroding in what looks like doubling, especially on mintmarks that people confuse with repunched mintmarks (RPMs).

The final type is “Reduction Lathe Doubling,” really a production issue that happens when a design is transferred to a master hub by a lathe vibrating slightly. The doubling is subtle and again, not valuable. It looks like machine doubling and really is just a category of it.

If you would like to learn more about the minting process, click here.

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You can find more information about types, varieties, errors, grading, bidding and buying in Coin News Updated: The Essential Guide to Online Bidding. Please consider buying or gifting the work for a friend, as it underwrites this hobbyist blog. Thank you.

By Jack Riley

Counterfeiters aren’t numismatists. They often use incorrect design types that are impossible for a given coin and do not understand how third party grading services holder the coins they certify. This example may take the cake! A counterfeit 1892-CC $20 Gold piece in a fake PCGS holder. Not just any holder, a holder pedigreed to D.L. Hansen!

Let’s view the counterfeit example compared to the genuine one below that from Hansen’s collection.

When you compare the two, it is very clear that they are not the same coin. One can see the CC position is incorrect along with a large lump on the ribbon.

The “Family” is likely very extensive and many dates have been noted sharing this common reverse. Additional images shared below are from an 1891-CC coin as well as an 1893-CC. These were recently shared to a large Facebook group where they got mixed reviews.

Now to the connection between the common reverses. This 1882-CC shares the “common reverse.” The obverse is very distinct as well for this date. The 1882 date was interchanged with both P and CC mint reverses. Noteworthy: the surface lump above Liberty’s head, spike protruding from the bridge of the nose, and a raised line under the date.

Interesting occurrence with the Philadelphia reverse is that it was later tooled to repair the denticles. The first two images show a depression along with the deformation of the denticles at approximately K12.

The next two images show the deformed denticles but no indentation within them.

“Common” P reverse

Closeup images of markers include:

• Deformed Denticles with a depression, later was repaired
• Spike through “C”
• Small field dot above “T”

“Common” CC reverse

Closeup image of repeating marks include:

• CC centered above denomination
• Small chip above “DOLLARS”

If you purchase a counterfeit coin, especially one as expensive as a $20 gold one, contact the seller for a refund. If the seller refuses to accept a return for a counterfeit coin, immediately initiate a dispute with the payment platform (eBay, PayPal, or credit card company) for an “item not as described,” as counterfeit items are illegal to sell. Document the fraud with professional authentication, and if necessary, report the seller to the U.S. Secret Service or local law enforcement.

If a dispute cannot be resolved, and you report the fraud to the U.S. Secret Service, you may be required to turn the coin over to authorities. In any case, never attempt to re-sell the coin, even if you disclose that it is a counterfeit.

If you like posts like this, you can read more articles on counterfeit coins by Jack D. Young, Jack Riley, John Lorenzo and Michael Bugeja at this URL. Also, please subscribe so you can get our weekly newsletter and be informed whenever there is a new article or column.

Proxiblog also has thousands of followers on Facebook Coin Groups, YouTube and other venues. To get the latest discussion and commentary, be sure to friend us by clicking here.

You can find more information about errors and varieties as well as buying and bidding on coins in Coin News Updated: The Essential Guide to Online Bidding. Please consider purchasing the work for yourself or a friend, as it underwrites this hobbyist website. Thank you.

By Jack Riley

This started on December 26, 2024, when I stumbled across an eBay listing of two Trade Dollars. Both “Bodybagged” by two separate TPG services. NGC returned one as “altered surfaces” and PCGS as “questionable authenticity.” Upon reviewing the images and referencing John Coxe’s attribution guide to Trade Dollar varieties, they didn’t match any known variety.

After a while of internet browsing I stumbled across a Heritage Auction listing of this previously unknown variety. After correspondence with John Coxe, I learned this new genuine variety is to be listed as the 1875cc C-17 when the SSDC site is updated as the last update was in 2022.

NGC example

PCGS example

Now to the coins! Not only did these two match a C-17 but they shared a number of circulation marks indicative of counterfeits. Interestingly both passed a sigma test for 90% silver, along with weight and dimensions being within tolerance of genuine Trade Dollars.

Sigma Metalytics test

Upon review of the obverse, I found there are a number of characteristics indicating these are struck counterfeits. I highlight three primary pickup points of the obverse to distinguish these from genuine counterparts.

• Indentation in the denticle below the base of 1
• Depression in the center below Liberty’s knew
• Field depression adjacent to the star and forehead

Reviewing both examples, the reverse shares a number of repeating circulation marks. However, many are minute and difficult to photograph. Primary pickups are as followed:

• Linear depression of the 9 in “900”
• Diagonal line through “R” in the motto

After sharing these with my friend Jack Young another example surfaced on Ebay a short time later. Now residing in a private collection it is safe from the market!

In preparation of this updated article an example surfaced on eBay certified by PCGS. This is the only example I have seen of this in an authentic TPG holder. It is noteworthy to mention the certification photo indicates it was certified in PCGS’s Chinese facility.

With only a few of these struck counterfeits being seen within the last year, it is safe to assume more exist and may already be in private collections. While the genuine variety itself appears to be scarce, it is unlikely to stumble across one of the struck counterfeits, but nothing is impossible. Actually a very easy variety to spot with CC set further right than any other variety of the date along with a hub break of the “I” of “UNITED”.

If you like posts like this, you can read more articles on counterfeit coins by Jack D. Young, Jack Riley and Michael Bugeja at this URL. Also, please subscribe so you can get our weekly newsletter and be informed whenever there is a new article or column.

Proxiblog also has thousands of followers on Facebook Coin Groups and across social media. To get the latest discussion and commentary, be sure to friend us by clicking here.

You can find more information about errors and varieties as well as buying and bidding on coins in Coin News Updated: The Essential Guide to Online Bidding. Please consider purchasing the work for yourself or a friend, as it underwrites this hobbyist website. Thank you.