§ Metric conversion table. Inches Millimeters (mm) 8/64 equals 3.2 16/64 equals 6.4 24/64 equals 9.5 32/64 equals 12.7 40/64 equals 15.9 48/64 equals 19.1 51/64 equals 20.2 52/64 equals 20.6 54/64 equals 21.4 56/64 equals 22.2 1 equals 25.4 18/64 equals 28.6 116/64 equals 31.8 124/64 equals 34.9