Hi according to the R.S.Yeoman Redbook a Dimes Diamention is:
DIMES
DRAPED BUST 1796-1807 19MM
CAPPED BUST 1809-1837 18.5MM
LIBERTY SEATED 1837-1891 17.9MM
BARBER 1892-1916 17.9MM
MERCURY 1916-1945 17.9MM
ROOSEVELT 1946-2008 17.9MM
BUT WHAT HAPPENS IF YOUR IN A AREA THAT COULD POSSIBLY HAVE
HAD A HALF DIME LOST THERE AND YOUR USEING A SAND SCOOP
W/ ALL THEM BIG HOLES IN IT, YOUR GOING TO LOSE THE HALF DIME
HALF DIME DIAMENTION:
FLOWING HAIR 1794-1795 16.5MM
DRAPED BUST 1796-1805 16.5MM
CAPPED BUST 1829-1837 15.5MM
LIBERTY SEATED 1837-1873 15.5MM
SO BIGGER IS NOT ALWAYS BETTER
MM INCHES INCHES
15 0.59 9.45/16
SO ITS BETTER TO USE A 9/16" DRILL BIT
JUST TO COVER YOUR BACK FORTY
Dave