How many is too many?

Will the string of summer sellouts continue when the John F. Kennedy Coin and Chronicles set goes on sale Sept. 16?

The U.S. Mint hopes so, but in a slower and more dignified manner. It doesn't want 15-minute sellouts or website glitches.

What it will get remains to be seen. The Kennedy set mintage was pushed up to 50,000 after the Truman and Eisenhower offers of 17,000.

At some point, collectors could lose interest in the sets as mintages pass the level where they figure they can make a profit on them on the secondary market.

However, 50,000 is still not so high that it will likely cause much discouragement.

The set costs just $57.95. It is considered affordable by many, especially if you throw in the possibility that lucky buyers will be able to double or triple their money by selling them online. Even higher profits might accrue if the pieces in the set are slabbed in top grade and called early releases.

Speculation is not a proper long-term support for collectible coins, but it works wonders for interest levels in the short term – especially knowing that if the Kennedy coin sells out, the Lyndon Johnson piece that will follow will be another slam dunk with a lower mintage.

For the long-term, the question is how collectors will take to the reverse proof Presidential dollars in these 2015 sets. The standard proof did little to excite basic collector interest.

But when the proof dollar became a reverse proof, collectors reversed their opinion of the Coin and Chronicles set and promoted it to the top of their shopping lists.

Buzz blogger Dave Harper has twice won the Numismatic Literary Guild Award for Best Blog and is editor of the weekly newspaper "Numismatic News."