1/4" x 19 BSPF HSS Tap Set - Goliath HSS Bright Finish BSPF Hand and Machine Tap Set. Pipe taps are much shorter than a similar size of regular hand tap, but the design features are the same. Goliath HSS taps provide a high hardness to toughness ratio, compressive and tensile strength, good abrasion resistance and resistance to micro-chipping, ensuring a long tool life. British Standard Pipe - G Series (BSPF) 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. Taper Taps have a lead of eight threads and are used as a starting tap in difficult or high precision holes. Intermediate Taps have a lead of four threads and are used in most general purpose applications to cut a thread true to a pre-drilled pilot hole. 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. Manufactured from HSS this general purpose tap is designed for use in medium tensile materials and is for hand or general machine use.