NPTF, ANPT

nptf-anpt_01

nptf-anpt_02

nptf-anpt_03

NPTF Threads are also known as Dryseal threads as they do not require a sealant to form a leak-proof joint.

Type Standard Plug gauges Ring gauges
NPFT ANSI/ASME B 1.20.5 Thread plug gauges L1 & L3
(Basic Step or Min/Max Step) 6 Step Crest Check Plug
Thread ring gauges L1 & L2 (Basic Step or Min/Max Step) 6 Step Crest Check ring
ANPT SAE SA71051B Thread plug gauges L1 & L3
(Basic Step or Min/Max Step) 6 Step Crest Check Plug
Thread ring gauges L1 & L2 (Basic Step or Min/Max Step) 6 Step Crest Check ring
  • NPTF & ANPT threads require additional gauging as the truncation of these threads should be maintained within specified limits.
  • L1 & L3 plug gauges and L1 & L2 Ring gauges are used in combination to verify the size and taper of the component threads along the thread length.
  • 6 Step Crest check plug and ring gauges are used to verify the crest diameter and truncation of the component threads along the thread length.
Check the PDF