BSPF (G SERIES) (British Standard Pipe) Chrome Alloy Hand TapThis series is a pipe thread which is used mainly for mechanical coupling. The angle of thread is mainly 55 however for the US method some threads have a 60 angle. It is specified according to JIS and ISO R228. Bottoming Taps have a lead of two threads and are used to ensure minimum thread run-out when tapping to the bottom of a blind hole. Bottoming Taps are typically preceded by the use of a Taper or Intermediate Tap.