Many mid to late 1960 coins are titled SMS 'Special Mint Set', are all of a certain era this SMS? What causes these to be SMS? If they're not all, how do you tell what SMS is?
From 1965-67 the mint didn't produce any proof sets. They in stead made Special Mint Sets which were somewhat proof like. SMS coins tend to be highly reflective and well struck but don't have quite the same quality as a proof. Sometimes it is very difficult to tell a SMS coin from a normal business strike apart because the differences can be quite subtle.
SMS - Special Mint Sets - were minted for collectors in 1965, 1966 & 1967. During those tumultuous years at the Mint (severe coin shortage, end of silver coinage and beginning of clad coinage, temporary removal of mintmarks, etc.) Proof Sets were not released. SMS coins fall somewhere between Business Strike coins and Proof coins. SMS coins have more detail than Business Strike coins because they were struck once with more pressure than Business Strike coins. If my memory serves me, the dies and planchets were not polished like Proof coins. Proof coins, on the other hand, are struck twice or more under high pressure so they have even better detail. And they are struck on polished planchets with polished dies. Hope this helps.
The best way to learn to identify them is to buy a set and compare them to a normal business strike. As has already been said, the complete SMS sets from each year and very inexpensive.
Presidents Many of the new Presidential Dollars are NGC slabbed with SMS (Satin Mint State)grades, whereas PGCS uses SF (Satin Finish)
This is true too. For the last several years the mint sets have had a special satin finish and are referred to as SMS as well. But those are different from the sets from the 60s.
