Overdate

I too would like to know if anyone really knows that one. I've heard so many different explanations over the years that I really wonder if anyone knows. I can see the explanations of an RPM but many overdates don't make CENTS. For example why would there be so many 1942/41 Mercury dimes? With coins minted of over hundreds of millions, why bother to try lining up a coin for a new date? Then too some are vague and I really wonder how they were ever figured out. The Indian Head cent 1888/7 or is it 8/8 or 8/9? Of course 8/9 may be a little nutty for me to say. I can't tell and wonder if anyone really can why this all happens.

This topic has been covered pretty well. At least for 19th C. overdates, the primary cause is probably economics, where a surviving die from the previous year's run is impressed with a new date. This can be documented when overdate dies match strikes from the previous year. Some cases might be unused dies from the prior year or new dies were mistakenly impressed with an older date punch and fixed- there is no real way to know because mint records never disclose mistakes. The only evidence we have is what remains of the prior date--after the majority is polished away of course.

Thanks to a friend, here's a great example of a doubled-hubbed overdate, which shows on most of this Australia 1933 1d.
I would call this a 1933/1932 overdate because two whole dates are involved.



The number of digits repunched depends a lot on the processes used to make the die. I have quite a few overdates from Sweden, where only the last 2 digits were involved.
Overlays can help clarify what happened. This overdate has been confirmed as a 1875/74.




Sometimes all 4 digits were obviously repunched, as in the case of this 1901/1891 ½ Dinero from Peru:



Btw, that's one nice 1797 large cent!

The overdated Working Dies were re-processed by grinding down and polishing away as much of the overdate as was possible. Each die was identified, and re-worked to remove traces of the underlying "3" in the last numeral of the date.
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OverdateA variety created when all or part of the date is engraved over another date on a die, part of the old date is still visible under the new one. For example, the 1942/1 Mercury dime.
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Overdate - A variety in which at least one digit of the date has been hubbed over or altered to a different number in the die.
Recessed - The lowering or sinking of a specific area on a coin, usually the date, so that it does not wear as quickly.
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Obviously per this article on mimi.hu and several other sites the over dates are not double die coins at all. They are simply reused dies from one date, ground down and a new date entered. If the process is incomplete, some or parts of the previous dates appear.
Per a Google search of overdates it appears that this is the case in all entries. Not sure how to Link those but one is https://www.bestcoin.com/overdate-error-coins.htm
Like I said I'm not a good Link person but a search on Google produced numerous stories about over dated coins and none are explained as double dies.

Coppercoins (naturally) has it right, specifically for US coinage of the 20th C. It could also be said that no RPDs were possible after working hubs were dated.

That said, there are a few exceptions to 20th C. overdate coins, where new digits were individually punched into dies. For example, the Copenhagen mint (Denmark) repunched individual digits into dies when making coins for Iceland prior to the 1940s. I'm sure something similar was done on my Sweden overdates 1912/1 and 1906/5. The first two digits were on the hub, the second two were added later--shown by the different positions on individual coins. At some point, everyone went to dated hubs in the 20th C., but for earlier coins there's quite a mix of methods used on dies of coins I collect.

Btw, I read this at the site mentioned above--isn't that the general consensus for US 20th C. overdates?