Here's an Overview of Our NPTF L-2 Ring Gages

NPTF L-2 Ring Rages are used in conjunction with NPTF L-1 Rings, where it is used to inspect the wrench engagement threads of a coupling and the taper of the external threads. They are manufactured as per the ANSI/ASME B1.20.5 standard. WESTport provides a free certfificate traceable to NIST with each ring gage.

L2 rings are also called the thick ring and that is used to check the thread element of those threads that have been engaged when tightened with a wrench. They are used in conjunction with the NPFT L1 gages and ensure dimensional compliance of the rings of the equipment or part in question.

How They Are Used:
The NPTF L-2 Rings are used as a check on taper where its engagement in the L-1 and L-2 dryseal must be within “One and a half” turn of the difference between the basic turn engagement of the ring gages. Basically, you are using the NPTF external ring gages in a similar fashion to pipe plug gages. The only difference is the measurement of the external gage instead of the internal.

NPTF L-2 Rings are not just for the second half, but also the required half for the measurement of the fifth, sixth, and seventh threads. The L2 in the name is a representation of the dimension in the thread specification that coincides with the “Wrench Tight Engagement Length”.

After the use of NPTF L-2 Ring Gage, a final check involves the use of a plain tapered ring gage, which is also called the NPTF 6 Step which helps in the measurement of the major diameter of the external thread of the part in question.

More on NPTF 6 Step Rings:
NPTF, along with ANPT (Aeronautical National Pipe Taper) external threads are first graded with NPTF L-1 Ring Gage for the measurement of the first five rings. The gage is hand tightened and the parts being checked are considered acceptable when they come flush to the end of the ring to plus or minus one turn of the unmarked side. The L-1 ring is also called the thin ring which is followed by the thick or the L-2 ring for checking the approximation of the rings or threads from fifth to seventh. With special emphasis on thread tolerance, the 6-step ring is used in the end.

Similar to the L1 ring, the L2 ring is also used as per the count of the number of turns that determine the distance traveled by the ring over the object in question. L-1 and NPTF L-2 Rings together inspect the lead, taper, pitch and minor diameter. The face of the rings should not vary more than ½ turn to the relative position of the small end of the pipe and the basic gaging with the use of both L-1 and NPTF L-2.

At WESTport Corporation, we have been providing industry world-wide with precision measuring instruments and calibration services since 1989. WESTport employs state-of-the-art measures to ensure all our products comply with the ISO 9001, and ISO/IEC 17025 standards. Moreover, our expanded product line includes (but is not limited to):
  • Thread and Plain Gages
  • API Plug and Ring Gages
  • Taps and Dies
  • Medical Gages
  • Spline Gages
  • Full-service Metrology Laboratories for tool calibration, repair, and onsite services

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