We all know that a proof coin is different from a business strike due to it's method of manufacture. They are struck multiple times with more pressure. They are struck using highly polished dies with laser etched devices to give the mirror fields and frosted devices (at least for modern brilliant proofs) and as such a proof coins is always a proof coin regardless of it's grade because of how it was made. From 1965-1967, the US mint stopped making proof sets and normal mint sets and instead made "Special Mint Sets" which contain coins that aren't really circulation business strikes...but also aren't proofs. They are almost something in between (or so I have always assumed). What I have wondered for a long time is this...how were the SMS coins manufactured compared to the circulation business strike coins from those years and proof coins from that era (1964, 1968, ect.)? How the did the strike pressure, number of strikes, die preparation differ from these three types of coins?
Excellent questions, all. I believe that one major difference is that all SMS coins were struck only once. I also know there is a way to tell the difference between an SMS coin and a really nice circulation strike from 1965-67. I don't know exactly what it is, but I do know there is a way.
Amazing.. did you see this thread I created this morning? - https://www.cointalk.com/threads/special-mint-sets-post-your-sms-mint-errors.308134/#post-2947729
Here is some information I want to share with you - http://numismaster.com/ta/numis/Article.jsp?ArticleId=9469 and https://www.thespruce.com/what-is-a-special-mint-set-768864
Actually I didn't...but those strike through errors are cool. This thread is what finally sparked the idea of me asking the question: https://www.cointalk.com/threads/mint-set-or-proof-set.308139/#post-2947850 Thank you for the links. The second one especially answered my questions and confirmed that these coins truly are "between a business strike and a proof." This is what it said:
so... special dies, more strike pressure, and only 1 strike, but no special treatment for the planchets
@paddyman98 I knew how SMS cents were minted. Thanks for the interesting info about the rest of the coins of those years! Reed
