Taper thread gauges, manufactured in Pune.

Families covered
FamilyStandardRange
Taper gauges (NPT)ANSI/ASME B1.20.1Ring gauges: Basic & min/max stepView specifications
NPTF & ANPT gaugesANSI/ASME B1.20.5NPTF plug/ring: L1 & L3 · basic or min/maxView specifications
Taper pipe threadsISO 7-2Standards: ISO 7-2 · BS 21View specifications

External threads: when screwed on by hand, the basic step gauge should be flush with the component face within a single turn. Internal threads: with a min/max step gauge, the component face should sit flush between the minimum and maximum step limits.

Common questions

Questions about taper thread gauges

What is a taper thread gauge?

A taper thread gauge checks a taper pipe thread, which seals by the taper fit itself rather than a separate sealing face, using a basic or min/max step gauge instead of a parallel GO / NOT-GO pair.

Which standards does Accusize cover?

NPT to ANSI/ASME B1.20.1, dry-seal NPTF to ANSI/ASME B1.20.5, ANPT to SAE AS71051B, and ISO 7-R / BSPT / PT taper pipe threads to ISO 7-2, BS 21 and JIS B0253.

How is a taper thread gauge checked, since there is no GO / NOT-GO?

On external threads, the basic step gauge should sit flush with the component face within a single turn when screwed on by hand. On internal threads, the component face should sit flush between the minimum and maximum step limits of a min/max step gauge.

What members are available?

NPT ring and plug gauges in basic and min/max step; NPTF L1 & L3 plug and L1 & L2 ring gauges plus ANPT 6-step crest crack members; and ISO 7-R / BSPT / PT taper pipe thread gauges.

Do you make special or non-standard taper thread gauges?

Yes. Alongside standard NPT, NPTF/ANPT and taper pipe thread gauges, we also make non-standard designs to drawing: extra lengths, air grooves, pilots and depth steps.

How do I request a quote?

Share the thread size, standard or a drawing on our quote page and we will confirm the class, availability and pricing within one business day.

Need taper thread gauges?

Share your thread, standard or drawing and get the right acceptance class, certified.