Description

Bordo NPT Bottoming HSS Hand and Machine Tap - 3052

HSS NPT Bottoming Hand and Machine Tap.
National Pipe Tapered is a US standard for tapered threads used to join pipes and fittings.
ANSI/ASME standard B1.20.1 covers threads of 60° form with flat crests and roots.
The taper on NPT threads allows them to form a seal when torqued as the flanks of the threads compress against each other.
However a clearance remains between the crests and roots of the threads, resulting in a leakage around this spiral.
This means that NPT fittings must be made leak free with the aid of thread seal tape or a thread sealant compound.
For each 12" increase in distance from the end, the diameter increases by 3/4".
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.