§ 51.3212 - Metric conversion table.
§ Metric conversion table. Inches Millimeters (mm) 1/8 3.2 1/4 6.4 3/8 9.5 1/2 12.7 5/8 15.9 3/4 19.1 7/8 22.2 1 25.4 11/4 31.8 11/2 38.1 13/4 44.5 2 50.8 21/2 63.5 23/4 69.9 3 76.2 31/2 88.9 4 101.6