What was the process for overdating dies?
MrEureka
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For example, take a look at the date on this 1817/4 Half Dollar. How did the Mint remove most of the traces of the original "4" in the date? And while we're at it, why wouldn't they remove the entire digit?
Andy Lustig
Doggedly collecting coins of the Central American Republic.
Visit the Society of US Pattern Collectors at USPatterns.com.
Doggedly collecting coins of the Central American Republic.
Visit the Society of US Pattern Collectors at USPatterns.com.
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Volumes have and will been written about this question. I must go and meet the parents of my stepdaughter’s boyfriend, but will offer some thoughts later.
See From Mine to Mint for details, etc.
Three methods were commonly used. "Success" depended on making the original numeral "go away," - i.e., invisible on a coin.
Start with unhardened die.
#1 Crude. Repunch with a different digit, and allow the metal to flow wherever it wants depending on geometry of original and new digit, and exact relative positions of both digits. Minor abrasion of any newly raised edges so they match existing field.
Result. Clear overdate with much of original date visible. Considerable variation in details.
#2 Better. Fill original digit with steel or iron wire, or filings/metal dust. Compress with original digit punch. Smooth surface to match field with abrasive. Punch new digit and again smooth.
Result. Overdating can range from invisible to obvious depending on mechanical strength of filling. Portions of filling might be excellent and others might not hold up well.
#3 Best. Use a graver or fine drill to undercut original digit. (This is what a dentist does in preparing to fill a cavity.) Also, create roughness to help mechanical bonding. Fill with soft die steel until slightly over-full, then compact with graver or original digit punch. Smooth surface to match field. Punch new digit(s). Smooth again.
Result. Properly done, this work is invisible. However, some portions might be stronger than others. This accounts for fragments of the original digit(s) being visible. Most common examples are 1880/79 Morgan dollars and 1900-O/CC dollars.
Note: The simplistic idea "grinding off the old digit and punching in a new digit" is absurd. This would create raised mounds equal to the depth of the original digit on coins.
Agree with the above. As for the 7 over 4 image above one of two things occurred. A, the die-sinker grabbed the wrong number or B, with precious metal scarce in the quantity needed for circulation it was a left over strike from 1814.
Neither. The die sinker used the right punch in 1814 but the die did not get used in that year. In 1817 the die was overdated and used.
It was not an 1814 coin struck a second time in 1817. The crossbar of the 4 would have been flattened by the field of the steel die, and because of the different positions of stars and letters from one die to another there would be double striking evident all over the coin.
From what I understand, if a die has been used to strike coins before, changing the date, with an overdate, is hard and yields mixed results. If the die has never been hardened, the process is easier.
The previously used die must be softened again by heating and then hardened by heating and quenching after the overdate is punched in. This is why it is rare to see a die used to strike a normal coin and then used again to strike an overdate.
I think that the 1806 over 5 quarter is one of the rare examples of this. The trouble is the re-harded die is often not very durable and does not last very long.
I the early days of the mint, dies were prepared with the last digit of the date left off until the die was to go into production. That’s why you see odd looking digits on some early coins. One example is the large and small 7s that appear on this 1797 half dime.
Until at least 1823, as @RogerB described in #1. When metal is impressed with a punch, the metal is displaced, as metal does not compress. The path of least resistance for the displaced metal is the under-digit cavity, which partially collapses with the displaced metal. Thus, the over-digit is always the strongest after final lapping. The die would have to be in an annealed state before punching.
There are both blundered dates and left over dies that were over-dated. In 1805 there were both. The O.101 & 102, T-4 and T-5 were from the old hub from an unused die dated 1804. The O.103, T-11 was a blundered date that came later in the year with the new hub:
In general, I don't believe the First Mint was that concerned with over-dated dies, they wanted to extend use if possible. There were no contemporary complaints of overdates that I am aware of, just a few design complaints. Some are not that obvious. With the number of brockages, 10%+ off-centers, rotated double strikes, heavy adjustment marks, and planchet de-laminations, the overpunched numbers and letters were minor in comparison. Nobody complained except numismatists with 10x loupes. If Scot knew his overdated dies would be magnified 50x on the internet, he would have been more careful!
@BillJones:
Another rare example is 1806/5 O.104, T-1, the first in the emission of 1806 half dollars. The over-dated obverse die was used several times in 1805, and did not last long in 1806:
Nysoto's bottom photo (O-103 T-11), is a good example of punching one digit over the original with no attempt to repair the area first. An Unc example might show slight depressed areas due to metal upward deformation.
As the OP's question was not date specific, you need to add #4 Hub a die to the point that at least part of the date is formed, if not all, and finish the die with a dated hub of a subsequent year.
Pop Quiz: Name a popular pre-1902 U.S. Overdate that was created using only one punch, not two different punches.
To illustrate how much metal can be deformed in the die using method #1, Look at the Mint Mark area on an 1854-O "Huge O" Quarter. Look at how the R & D are partially collapsed, as well as the arrow feather and branch above the O.
Interesting thread.... I learned a bit today... always a good day when that happens...I have the Morgan 1900 O/CC... I will pull that out and look at it again with this information. The coin has clear features, so it will be a good one to study. Cheers, RickO
Thinking of the 1851/81 cent, but this would technically be a repunched date rather than an overdate, as it didn't involve re-dating a die, simply covering up a screw-up. A few others come to mind, including 1809/6 half cent, 1858/inverted date half dime,
Keeper of the VAM Catalog • Professional Coin Imaging • Prime Number Set • World Coins in Early America • British Trade Dollars • Variety Attribution
Bingo! 1839/6 and 1844/81 cents as well, plus the 1865-S $10. The hobby considers them to be overdates, even though they are technically blundered dies.
Item #4 was omitted because the question was about overdating, not completing a date with a separate punch. (An exception would be a die with complete or partial date on a logotype punched in upside down....)
The entire lower reverse of the 1854 "Huge O" quarters has a lot of deterioration going on. I wouldn't necessarily ascribe the deformation of the nearby letters to the heavy mint mark punching.
The O mint marks would have normally been punched into the dies in Philadelphia before the dies would be shipped to New Orleans. It is probable that the Huge O came about because the die details in the area of the mint mark were corrupted and someone at the New Orleans mint recut the O mint mark (rather heavily, of course). The re-cutting was done by cutting metal away, not by punching.
I did, however, perform a few over-punching tests (in die steel) a couple years ago.
I used small "O" and "S" punches to simulate an O/S (similar to the 1882-O/S Morgan Dollars).
The picture below shows how the O punch caused the initial S punch to partially close up and become thinner near the boundaries of the O.
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I respectfully but firmly disagree.
Just an interesting coin...
Doggedly collecting coins of the Central American Republic.
Visit the Society of US Pattern Collectors at USPatterns.com.
The California ten Mr. Eureka posted looks like a rough drill-and-fill. I.e., Use a common metal drill to make a hole (or partial hole) were the original digit was, fill with a steel plug, restrike with a new digit. Quick and cheap to do.
After reading all your thoughts and trying to grasp all the tech. talk.
What would be the purpose for some thing like this?
A clear S inside the letter B in liberty. Sorry for the intrusion, buts its been on my mind for a while.
Technical question. There are some overdates from a specific period (1877/6 Half, 1880/79 various Dollars) that show very definite remnants of the underdate atop (i.e. in the highest relief) the overdate. How does this happen vis-a-vis the above possibilities, and is it possible there was a short-lived different technique?
You'll find instances in the bust half world of "overdates" that were nothing more than re-engraved numerals. The 1824/4 O.109 is an example. The numeral 4 was usually hand-sculpted, not punched. Nonetheless, it is a Redbook variety and registry required.
Lance.
Punching over an existing date digit does not necessarily obliterate the under digit. Metal does not really "flow". It bends.
Just like when adjustment marks on a planchet are not struck out by the die.
The 1880/79 overdates are fascinating. Some only show the remains of the underdates deep in the die, such as the P-mint VAM-23, while some of the CC's show strong outlines at the level of the field. My favorite is of course the P-mint VAM-6. I used to own a nice AU of it.
Great thread!
My 1866 Philly Mint Set
Slightly earlier die state but not unc
And a just in your face example
