Precision gauging for oil & gas threads.
Oil and gas fittings typically rely on a taper thread to make the seal, rather than a separate gasket or O-ring, so the gauge has to verify the taper and depth of engagement, not just a diameter at one point.
NPT and dry-seal NPTF
NPT gauges to ANSI/ASME B1.20.1 check a standard taper pipe thread using a basic or min/max step: on an external thread, the gauge should sit flush with the component face within a single turn when screwed on by hand; on an internal thread, the face should land between the min and max step. NPTF gauges to ANSI/ASME B1.20.5 check the dry-seal variant, where the thread crest and root are deliberately interference-fit.
ISO 7-R, BSPT and PT taper pipe threads
Where the governing standard is ISO 7-2, BS 21 or JIS B0253 rather than NPT, taper pipe thread gauges to the matching standard verify the same taper fit on a 55° thread form.
Getting the right gauge
The first step is identifying which taper standard the drawing actually calls out. NPT, NPTF and ISO 7-R / BSPT / PT threads look superficially similar but are not interchangeable, and a gauge built to the wrong one will give a false acceptance. Once the standard is confirmed, we also build non-standard pipe thread gauges to drawing: extra lengths, air grooves, pilots and depth steps.
Gauge families used for this inspection
Questions about oil & gas
Which gauge families are typically used in oil & gas inspection?
NPT and dry-seal NPTF taper gauges, plus ISO 7-R / BSPT / PT taper pipe thread gauges.
Which standards apply?
NPT to ANSI/ASME B1.20.1, NPTF to ANSI/ASME B1.20.5, and taper pipe threads to ISO 7-2, BS 21 or JIS B0253.
How is a taper pipe thread checked, since there is no GO / NOT-GO?
With a basic or min/max step gauge: on external threads the gauge should sit flush with the component face within a single turn; on internal threads the face should land between the min and max step.
Are NPT and BSPT interchangeable?
No. They are both taper pipe threads but to different standards and thread forms, so a gauge built to one will not correctly accept or reject a part made to the other.
Do you make non-standard taper pipe thread gauges?
Yes, we build 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.
Tell us what you are inspecting.
Share your thread, standard or drawing and get the right acceptance class, certified.