Overdates: Let's get technical!
MrEureka
Posts: 24,355 ✭✭✭✭✭
Most overdates show a weakened "under-date". For example, consider the underlying 4 under 7 on the 1817/4 half dollar.
On that coin, what was the process by which the 7 was placed over the 4? Was there any separate attempt to remove the 4?
Why didn't the metal around the 7/4 on the die bulge upwards? If it did, how was it evened out?
Are there (probably) a lot of overdates that show no sign of the under-date?
What else am I missing?
On that coin, what was the process by which the 7 was placed over the 4? Was there any separate attempt to remove the 4?
Why didn't the metal around the 7/4 on the die bulge upwards? If it did, how was it evened out?
Are there (probably) a lot of overdates that show no sign of the under-date?
What else am I missing?
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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Comments
On that coin, what was the process by which the 7 was placed over the 4? Was there any separate attempt to remove the 4?...they can't remove a deep impressed stamping
Why didn't the metal around the 7/4 on the die bulge upwards? If it did, how was it evened out?....i would imagine they ground and polished it flat before re-hardening the die for use
so it was ground flat in that area
Are there (probably) a lot of overdates that show no sign of the under-date? ...if they show no sign of an under date...how can they be an overdate?...as it has only one date
What else am I missing?...interesting times that happened at the mint...supervisor saying...."here...fix this for us" as the tool n die department was uh...ok
<< <i>If the die was worked on properly then it does not make over-date coins. >>
I suppose there's logic to that. But it would be possible to determine through attribution that the new coin comes from the same die (if previously used in an earlier year). Speaking of bust halves, e.g.
I believe, however, that CBH overdates were always made from unused dies.
Lance.
Assuming that the previously-dated die had not yet been hardened, he could just punch the new date over the old date and see what happened. Or, he could try to ease any work hardening in the date area caused by the first dating by re-annealing the die. In the few cases where old dies actually used to strike coinage were subsequently overdated, it is a safe assumption that the die was re-annealed before being overdated.
I assume that any punching of a date or a mint mark into an annealed die did "bulge up" a shallow crater ring around the impression. This would routinely be poilished off the die before it is used, but I have seen enough 20th century coins with depressions around the mint mark to know that sometimes they forgot. I would assume that a large date digit would leave a larger crater ring than a small mint mark punch.
If the crater ring from the first dating had been polished off before the second date was impressed into the die, then the overdating would only leave one crater ring. If it had not, they there would be two overlapping crater rings of different shapes.
Besides throwing up the secondary crater ring, the overdating would tend to partially collapse the initial impression. How much it collapsed and/or filled in would depend on the shapes of the two digits.
As I am writing this a thought occurs to me that perhaps the raised crater ring on the die would provide the engraver with some "extra metal" that he could "chase" into the unwanted portions of the original date. I shall have to consider this further.
TD
Great transactions with oih82w8, JasonGaming, Moose1913.
<< <i>Weren't the numbers of the date punched in one at a time? >>
Yes, as were the stars. In spite of some wags who liked the idea of gang punches, a silly notion. I'm not sure where you're going with this, though.
Some folks think old, unused dies were used as a matter of expedience. A little lapping and polish, maybe annealing, and good-to-go. I've read that simple, human-error might be to blame. It was a new year, 1814 perhaps, but the die was punched with 1813. Ever write a check in January with the prior year?
Whatever the cause and fix there's no doubt that overdates are special. A nice 1817/3 bust half is probably close in value to the regal 1815/2.
Lance.
<< <i>
<< <i>Weren't the numbers of the date punched in one at a time? >>
Yes, as were the stars. In spite of some wags who liked the idea of gang punches, a silly notion. I'm not sure where you're going with this, though.
Some folks think old, unused dies were used as a matter of expedience. A little lapping and polish, maybe annealing, and good-to-go. I've read that simple, human-error might be to blame. It was a new year, 1814 perhaps, but the die was punched with 1813. Ever write a check in January with the prior year?
Whatever the cause and fix there's no doubt that overdates are special. A nice 1817/3 bust half is probably close in value to the regal 1815/2.
Lance. >>
After reading CaptHenway's post I had the impression maybe I was wrong and not all dates were individually punched. I was just trying to contemplate the metal flow of
repunching a single digit vs an entire date at once into the die, then how to remove the under date. Just pondering all of this.
Great transactions with oih82w8, JasonGaming, Moose1913.
Sorry if I misled you.
Lance.
That's what I was originally thinking but I guess I was trying to get too scientific vs. logical.
Great transactions with oih82w8, JasonGaming, Moose1913.
Great transactions with oih82w8, JasonGaming, Moose1913.
<< <i>Two samples of the 1817/4 half. It looks as if these were from separate dies and both had the overdate handled in a different manner.
No, they're the same die. That first example is the latest discovered (the 12th coin I believe). It was mentioned in an article I read, when it first made it's appearance at the last ANA, that the coin had been tooled near the date.
<< <i>Weren't the numbers of the date punched in one at a time? >>
As I said, there were different techniques used at different times over the years. In 1817 they were punching one digit at a time. Some time around 1840 they started using gang punches.