Chris S. writes: I’ve found a 1931 mercury dime which shows strong doubling on the date and lettering on the obverse. How can I tell if this is machine doubling or an actual double die. I have found a 1939 jefferson double die which has been certified and the doubling on the dime looks very similar.
There exists a 1931-D Mercury dime doubled die. It’s very scarce and usually shows up in low grade. You’re correct about the doubling on the date as that is its strongest doubled feature. The inside serif of the first 1, the tail on the 9 the bottom of the 3 and the last one all show very obvious doubling. Hold on to it. It’s a rare coin!
I love the 1939 doubled Monticello nickel. You’re right, the character of the doubling should be the same as your dime.