I just made a two headed nickel.
I used a soft 5c collet and bored it to hold the nickel.
Then I made two nickels bored out to .800 dia x .036
deep.[ Half of coin.]
Then I faced and turned a piece of stock to .800 then
I put the bored out coin over the turned dia. Then I
used a live center pushing a bushing against coin to
drive it. Took light cuts about .01 and turned it to
..800 bore size. then I pressed coin slug into the bored piece
and ended up with two headed nickel with no seam showing.
Worked great.
Jim
Have pics if anyone interested.