Here's an Overview of the ANPT L-2 Ring Gage


ANPT L2 ring gage is the second ring gage that is used for the measurement of the external rings on components like fittings, pipes, plugs, etc. Before this, ANPT L1 ring gage is used which is for the purpose of determining the thread elements that are engaged when the component is Hand tightened. In contrast to that, the ANPT L2 ring gage is used to engage the thread elements that will be engaged when the component is wrench tightened

How To Use It?

ANPT L2 ring gages are used in conjunction with L1 rings as well as with the 6-step ring. However, L1 and 6 step rings are more commonly used in conjunction in contrast to ANPT L2 ring gage. The L2 gage measures the effective external threads that are situated beyond the L1 distance. The application of both, L1 and L2 gages are similar to a major degree with a difference in the count of the number of turns that the product travels or fails to travel, in case the piping of the component is determined to be faulty.

More On ANPT L-2 Ring Gage

ANPT or the Aeronautical National Piper Thread rings are different from the NPT or the NPTF thread rings, given that they are for aeronautical applications. The do not require the use of any sealants as the threads form an airtight mechanical seal that prevents any sort of leakage. This is why they are called “dry seal” threads.

Although the ANPT threads are similar to NPT threads, the difference in the application for aeronautical purposes dictates that they must be controlled very carefully for taper, thread form, and diameter. This is because up until the length of 2-inch size, the ANPT and NPT threads are almost identical and have a requirement of an L1 gage.

The ANPT L2 ring gage is for measuring the second half of the threads that are engaged when the component is wrench tightened After both, the L1 and L2 lengths have been checked, the ANPT 6-step ring is used which helps to measure the major and minor diameter of the threads of the part in use.

ANPT threads are measured in the same fashion as NPTF threads, both internally and externally (we use the ANPT 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 ANPT L-2 ring, a turn of 1 ½ from the basic turn is still acceptable for the L2 ring gage. 


WESTport Taper pipe ANPT L2 Ring Gage is available in a variety of styles and over a wide range of measurements. WESTport stands proud as an ISO 17025  manufacturer of quality assurance products with a commitment to client satisfaction and the provision of reliable products as an industry leader. Production units with regular and excessive use of Taper Pipe NPTF L3 Plug Gage are advised to have several spares at hand along with a master thread plug to regularly check on the wear and tear of their ANPT L2 Plug Gage.

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