Broken die occurs when there’s impurities in the alloy, created a weak fracture line in the planchet, that when struck by the force of the die it seperates into two pieces.
Worn and over-used dies can result in all types of anomalies but we’re referring to dies in which mint employees attempted to prolong the life of the die and inadvertently filed off design features. In return this created some valuable die varieties that are highly collected today. However, not all missing design features make a coin valuable, there’s many instances of a coin being struck through grease or over-filed to remove clash marks but no extra value is added.
It’s all about demand and if there’s two or more just alike and if it is sent in to be attributed by a professional with a press follow-up.
Trail dies are a result of the hubbing or die creation process and are die varieties but it is not completely understood how they’re created. Possible this is similar to strike doubling but caused by the squeeze method where the hub die drag on along the surface of the working die just after retracting from the squeeze.
1922 No D Lincoln Cent is not an example of an omitted mint mark, it was on the die but accidentally removed. Struck through grease filled die is also not an omitted mint mark.
Omitted mint marks are mostly known for proofs without the S, but there is a 1982 Roosevelt Dime without a P mint mark, but Lincoln Cents never had a P mint mark until 2017. So no mint mark cents are normal and where minted at the Philadelphia Mint.
Before the 1990’s mint marks were punched onto the die by use of a hand punch and were not initially part of the die’s design, and an RPM happened when it is punched out of position or to weakly punched, or when the punch broke and the mint employee attempts to punch it again and correct the mistake.
There’s several varieties for die scraped and gouges as well as feeder finger gouges and Rockwell test marks (small round raised area on a coin).
A die break is deeper than a die crack is actually a wider die crack, can result in a part of the die falling out and when it is rim to rim it is called a CUD. A CUD can be retained as in the image below or that part of the die can fall out and fill in with planchet metal forming what looks like a was of CUD; see first image.
A die crack occurs when the stress on the die begins to cause fractures in the die face, these die cracks are not deep but are the beginning of the end for the die. Die cracks rarely add any extra value to a coin, but can be used as markers for know varieties called PUPs (Pick Up Points). In some cases when two or more coins were found with the very same die crack they have been attributed as a variety.
A doubled die happens during the pressing process when the die itself is created and not during the strike of the coin. The doubled secondary will be the same height and width of the design and will not look flat like.
Values for doubled dies are all over the place and 1955 has at least 15 different doubled die varieties with only two worth a large premium and only one is the most famous doubled die in coin collecting. So it’s not enough to say it’s a 1955 DDO; it must also be the exact variety base on the die markers to assign a value.
With that being said most doubled dies don’t add much of a premium to a coin and master die doubling is even less than that. So it is best to seek professional advice when assigning doubled die varieties and their subsequent value.
There’s 8 classes of doubled dies listed below:
Double Die Classification:
- Class I: Die being re-hubbed is rotated near the center of the die from the position it was in during the original Hubbing.
- Class II: Design features on the Die/Hub become distorted or miss-shaped during the annealing/tempering process causing the images to no longer align properly when being re-hubbed.
- Class III: When working hubs with different designs features are used to Hub a Die.
- Class IV: When a Die is moved off center in the Hubbing Press from the position it was in during the initial Hubbing.
- Class V: When a Die is pivoted around a point near the rim during the rehubbing process.
- Class VI: When a Hub is overused and the design features become thickened or flattened creating thick design features on the Working Dies.
- Class VII: When a Die being Hubbed is impressed with a normal hub and a then re-hubbed using a hub that has had its features changed or removed
- Class VIII: When the top of a Die being Hubbed is not parallel to that of the Hub.
Strike doubling is an error and is caused by a loose die but it is NOT a Doubled Die. All strike doubling is considered machine damage and will show on the sides of the letters, numbers and bust as a flat shelf-like doubling, and is actually a flat on the side of a design element were the die actually pushed or slightly gouged the metal as it retracted from the coin’s surface just after it struck the coin.