"Size","UNC (TPI)","UNF (TPI)","Across flats F","Thickness H"
"1/4″ (6.35)","20","28","7/16″ (11.11)","7/32″ (5.56)"
"5/16″ (7.94)","18","24","1/2″ (12.70)","17/64″ (6.75)"
"3/8″ (9.52)","16","24","9/16″ (14.29)","21/64″ (8.33)"
"7/16″ (11.11)","14","20","11/16″ (17.46)","3/8″ (9.52)"
"1/2″ (12.70)","13","20","3/4″ (19.05)","7/16″ (11.11)"
"9/16″ (14.29)","12","18","7/8″ (22.22)","31/64″ (12.30)"
"5/8″ (15.88)","11","18","15/16″ (23.81)","35/64″ (13.89)"
"3/4″ (19.05)","10","16","1-1/8″ (28.57)","41/64″ (16.27)"
"7/8″ (22.22)","9","14","1-5/16″ (33.34)","3/4″ (19.05)"
"1″ (25.40)","8","12","1-1/2″ (38.10)","55/64″ (21.83)"
"Reference only — confirm against drawing. ASME B18.2.2. REL India"