TUBE OD UN / UNF S L D PART NO. mm Inch N mm mm mm 6 1/4 7/16 -20 14 17 9 4F-CAP 8 5/16 1/2 -20 17 19.5 10.5 5F-CAP 10 3/8 9/16 -18 19 20.5 10.5 6F-CAP 12 1/2 3/4 -16 22 23.9 13 8F-CAP 14/15/16 5/8 7/8 -14 27 27.1 14 10F-CAP 18/20 3/4 1 1/16 -12 32 31.6 14 12F-CAP 25 1 1 5/16 -12 41 32.8 17 16F-CAP 28/30/32 1 1/4 1 5/8 -12 50 35.47 19 20F-CAP 35/38 1 1/2 1 7/8 -12 60 43.2 21 24F-CAP