Since they started making 40% halves in 1965, why didn't they make the other denominations in 40% silver ie quarter and dime.
I believe it was done to honor Kennedy by not debasing his coin, as his assassination was still relatively recent in 1965.
From what I understand, the Western Silver producing states would not get on board with no silver at all so the 40% Silver halfs were put in as a compromise.
It doesn't directly answer your question, but Wikipedia's article on the Coinage Act of 1965 is definitely worth reading if you're curious about this.
They made 40% Silver halfs from 1965-1969, as Jaelus said, I also believe that this was done because of Kennedy's assassination.
As with many things, there were a number of factors going into this. The Franklin half was not that old, having only started in 1948 and so should still have had a number of years into it before the design was changed. If it had continued, I think that even with silver producing states opposition, that the half would have also gone with the no silver in 1965 and we would not have this discussion. Just like the Washington Quarter or the Roosevelt Dime, a change to silver would not have caused any problem. Silver older halves would have continued to be pulled because of the change, but minting more halves would have let it be ok. However, JFK was assasinated in late Nov, 1963, and there was a rush job to put him on coinage. So much so, and also the fact that Franklin was not the most popular real person on coins at that time and he had never been a president, compelled the halves to be the one to be changed. First mintings of JFK halves came in January 1964. That is fast, to have less than two months from someone dying to having his image on a major US coin. Also, there was not any public notice (forewarning around 1963, early 1964 to the general populace) that coins would lose the silver in 1965. Couple that with the reasoning that the Kennedy coins were also being hoarded rather than having general usage and the mint not wanting to make the 1964 coins a one-off silver issue (with no silver in any future ones) which could make the entire 1964 minting a waste of their time and effort. They still probably(my speculation) thought they could get past the hoarding of the first year issue and that halves would continue to circulate freely. But, in 1965-1972, these were the first years where that would not happen. And I don't think it was simply because of the Franklin half being changed. These were years that because the mint also removed mintmarks to discourage collecting and years where the larger bills and larger coins were less in favor for general usage. Fifty cents was no longer a big deal to people and it was much easier to simply use quarters instead of halves. It became a rarity to even contemplate seeing a 500 or 1000 dollar bill also. The last 1000 dollar bill had been printed in 1945 and so just over time it would have caused those not to be much in 'circulation'. The 500 dollar bills The last 500 dollar bill printing wasn't until 1969 and this decision reflected what I am talking about.... basically less than a decade when common usage types of coins/bills (to some extent, obviously not in common use everywhere for everyone) being so out of use that they became obsolete. After 1969, even hundreds (except for use in getting to other countries, as it is the favored unit when traveling to exchange for $$$ in crisp, new bills) became less common as a usage to most people. I believe that had Kennedy not died and immediately been given the half to commemorate him, there would have been a full debasement of metal in the Franklin half in 1965 and at some point, that unit may have ceased to be coined. Sometimes a person's death coming at just the 'right' time can make a huge difference in many other things. We now have to suffer having dollar and half coins basically only being minted (since 2002 for the Kennedy Half) to keep up production. None of them are being minted for circulation, though of course you do find them being circulated at times. We also have to suffer with coins like the small dollar coins. The only bright spot in continuing the larger issues is that the Ike was made. It has some character.
There couldn't have been because clad coinage wasn't approved until May of 1965, and it was the 40% silver in the halves compromise that got the votes from the silver producing states in the Senate. Without them the Coinage Act of 1965 and clad coinage wouldn't have passed. Oh I'm sure it would have eventually, but we may not have gotten clad coinage until 1966 or 67. Printing of both the $1000 and the $500 was discontinued June 26, 1946. In 1969 it was mandated that any $500's or $1000's received at banks be returned to the Fed for destruction. Before that time they could be reissued by the banks.
