Hey everyone ! So, Iv'e only been a member for about a month and I'm new to Errors (embarrassingly so ) . Well I recently learned about Longacre Double when I posted my 1882 IHC and asked if it was a Doubled Die Obverse . Instead of reciting, I decided to provide you with an excellent Link and my Pics of my coin . http://numissociety.com/content.php?135-Longacre-Doubling-A-discussion
Thing is most of the problems aren't errors at all but just post mint damage or PMD . Also, I see a lot of Dryer coins
I have always felt that Longacre deliberately added that small shoulder to the punches used to create the master dies as a visual aid so he would know when the punch had been driven deeply enough into the die. Longacre was not a die sinker, he was an engraver, in fact mostly a flat plate engraver. So he was not experience in knowing how deeply the lettering needed to punched. The shoulder also aided in die polishing/basining. When the shoulders disappeared the die would be properly basined and the lettering and devices would be at the proper desired relief above the field on the final coin. So a coin that still shows the Longacre doubling is from a die that wasn't properly finished. After Longacre died the master dies and hubs he had made continued in use so the Longacre doubling effect can be seen long after he passed. But whenever the hubs were modified after he died, even if the general design didn't change, Longacre doubling disappears. For example on the Indian head cent Longacre Doubling is common until 1886, On the later date Hub of 1886 coins Longacre doubling is not seen. On the reverse that the last modification was the hub of 1870 which Longacre must have made in 1869 before his death. That hub was used through the end of the series and Longacre doubling can be found on the reverse through at least 1907.
I sent this coin to NGC for a friend, noticed the Longacre doubling when I got it back. Shame about the grade though.