Npt 3 8 size July 8, 2019 16 32 64 128 Npt 3 8 drill size Npt 3 8 tap drill size 3 8 npt size in mm 3 8 npt drill size mm 3 8 18 npt drill size 3 8 npt size in inches 3 8 npt size chart 3 8 npt thread size 3 8 npt hole size 3 8 npt od size 3 8 npt actual size 3 8 npt id size 3 8 npt knockout size 3 8 npt wrench size 3 8 npt fitting size