An Overview of NPTF L-1 Ring Gages

NPTF L1 ring gages inspect the hand-tight engagement or the functional size of a part in question. This includes the male threads or the nipple that must conform to specific calculations before being deemed usable. NPTF L-1 RIngs are designed to conform to the ANSI/ASME B1.20.5 standards. Gaging the NPTF external threads requires using more equipment so it confirms the standards stated.

Screw thread pipe ring gages have two basic classes which includes plain and threaded. NPTF Rings L-1 belongs to the latter. The gage is threaded onto the pipe or equipment to be measured via hand.

More About NPTF Rings L-1:
NPTF is also called “Dryseal” because the thread tolerance is controlled very strictly. Still, the gages are used in a similar manner to plug gages except for the difference in the thread, which is internal in the case of pipe plugs and external in the case of rings. NPTF Rings L-1 is also called “thin” gage and parts that are measured on it are considered tolerable when they come flush to the ring’s end to a positive or negative one turn of the unmarked side, effective measuring the first 4 or 5 threads. For the further threads, NPTF L-2 ring gage is used which measures from the fifth to seventh threads.

About NPTF Threads:
NPTF threads are measured in the same fashion as ANTP threads both internally and externally (we use the NPTF L-1 ring for external measurement). But the gages are still dimensionally different which is why they cannot be used interchangeably. From the basic number of turns specified for the NPTF L-1 Ring, a turn of 1 ½ from the basic turn is still acceptable for the L2 ring gage.

Both NPT and NPTF have the same taper per inch, as well as threads per inch, the real difference lies in diameters (major and minor) along with the crest and the root of the threads. The threads of both, NPT and NPTF are designed differently, with the NPTF threads being designed to have a smaller range than NPT threads and interfere with the mating thread. This in turn creates a dry mechanical seal that prevents leakage without the use of a sealant. This happens because the NPTF threads are designed to have interference at the root and crest of the threads not just minor, but also on the major diameter. This results in a leak-proof connection.

NPTF L-1 Ring Gages from WESTport Corporation are ideal for measuring the external threads of pipes and/or other equipment and ensuring the said equipment or part in question falls within the said parameters. Using state-of-the-art technology and excellent customer service, we are thoroughly committed to ensuring we retain our status as one of the major quality assurance products and services. WESTport has been servicing industry worldwide since 1989 and is an ISO 9001 and ISO 17025 accredited manufacturer of quality assurance products.

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