1 Name: pipe thread tap, water pipe tap 

 2 material: high speed steel (HSS) 

 3 units: a branch 

 4 specification:

     divided into G represents cylinder pipe thread [55 degree]

     ZG stands for conical pipe threads [55 degrees] 

     Z stands for conical pipe threads [60 degrees] 

 5 purpose: reaming pipe fittings and internal thread of general machinery. 

      The 6-pipe thread taps are G, Z, ZG, NPT, RC, RP, PT, PF, NPS, NPSM, NPSF, NPTF, BSPT and other models. The most commonly used pipe thread tap old mark: G, Z, ZG, the most commonly used pipe thread tap new mark: NPT, RC new standard. Among them, RC=ZG, NPT=Z, PF (Japanese standard) =G can be used. 

 1 pipe ---1/8 (outer diameter 9.73)

 2 pipe ---1/4 (outer diameter 13.16 or so) 

 3 pipe ---3/8 (outer diameter 16.66)

 4 pipe ---1/2 (outer diameter 20.96 or so)

 6 in charge of ---3/4 (outer diameter 26.44)

 8 pipe ---1 "(outer diameter 33.25 or so)