TUBE OD UN / UNF S S1 L L1 L2 D PART NO. mm Inch N mm mm mm mm mm mm 6 1/4 7/16 -20 11 17 24.6 40.4 28.3 4.4 4F-EB 8 5/16 1/2 -20 13 19 26.2 41.1 28.3 6 5F-EB 10 3/8 9/16 -18 14 22 27.7 46 30.1 7.5 6F-EB 12 1/2 3/4 -16 19 24 34.5 53.6 35 9.9 8F-EB 14/15/16 5/8 7/8 -14 22 30 39.6 60.7 38.5 12.3 10F-EB 18/20 3/4 1 1/16 -12 27 36 45.2 67.8 42.8 15.5 12F-EB 25 1 1 5/16 -12 33 41 49 71 42.8 21.5 16F-EB 28/30/32 1 1/4 1 5/8 -12 41 50 55 76 44.1 27.5 20F-EB