3 8 is 18 July 8, 2019 16 32 64 128 3 8 is 18 eggs 3 8 18 npt 3 8 18 npt tap drill size 3 8 18 38 3 8 18 npt drill size 3 8 18 npt thread dimensions 3 8 18 nptf 3 8 18 tap drill size 3 8 18 tap 3 8 18 nptf thread dimensions 3 8 18 bolt 3 8 18 npsm 3 8 18 npt major diameter 3 8 18 thread