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NPTF 6 step taperpipe plug gage

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  • NPTF L1-L3 taperpipe plug gage
  • NPTF 6 step taperpipe plug gage
  • NPT L1 taperpipe plug gage
  • NPSM plug gage

Taperpipe Plug Gages

  • NPT L1 plug inspects the functional size or hand tight engagement of couplings or an internal thread
  • NPTF L1 plug inspects the functional size or hand tight engagement of couplings or an internal thread
  • NPTF L3 plug inspects the wrench engagement and taper of couplings or internal threads and is used in conjunction or relationship with the NPTF L1
  • NPTF 6 step plug inspects the crest truncation or profile of the internal threads and is used in conjunction with L1 plug
  • NPT pipe thread plug and ring gages are manufactured per ANSI/ASME B1.20.1
  • NPTF gages are manufactured per ANSI/ASME B1.20.5
  • Free NIST certificate of accuracy

  • NPT Plug Gage L-1
  • NPTF plug gage L-1
  • NPTF plug page L-3
  • NPTF plug gage 6-Step


Part# Product Name Size Price Sale Price
NPTP-01 Taperpipe NPT Plug Gage L-1 1/6-27 $90.00 $82.00
NPTP-02 Taperpipe NPT Plug Gage L-1 1/8-27 $70.00 $64.00
NPTP-03 Taperpipe NPT Plug Gage L-1 1/4-18 $74.00 $67.00
NPTP-04 Taperpipe NPT Plug Gage L-1 3/8-18 $81.00 $73.00
NPTP-05 Taperpipe NPT Plug Gage L-1 1/2-14 $91.00 $83.00
NPTP-06 Taperpipe NPT Plug Gage L-1 3/4-14 $105.00 $95.00
NPTP-07 Taperpipe NPT Plug Gage L-1 1-11 1/2 $116.00 $105.00
NPTP-08 Taperpipe NPT Plug Gage L-1 1 1/4-11 1/2 $130.00 $118.00
NPTP-09 Taperpipe NPT Plug Gage L-1 1 1/2-11 1/2 $147.00 $133.00
NPTP-10 Taperpipe NPT Plug Gage L-1 2-11 1/2 $180.00 $162.00
NPTP-11 Taperpipe NPT Plug Gage L-1 2 1/2-8 $215.00 $195.00
NPTP-12 Taperpipe NPT Plug Gage L-1 3-8 $250.00 $226.00
NPTP-13 Taperpipe NPT Plug Gage L-1 3 1/2-8 $375.00 $339.00
NPTP-14 Taperpipe NPT Plug Gage L-1 4-8 $417.00 $377.00
NPTP-15 Taperpipe NPT Plug Gage L-1 5-8 $583.00 $527.00
NPTP-16 Taperpipe NPT Plug Gage L-1 6-8 $694.00 $628.00


NPT L1 plug (American National Standard Taper Pipe) is used to check an internal threaded hole. The NPT L1 plug inspects the functional size or hand tight engagement of couplings or an internal thread. Parts being checked are generally acceptable when they come flush with the notch to plus (+) or minus (-) one turn.

NPT L1 taper pipe ring gages are used to check external threaded parts. NPT L1 rings inspect the functional size or hand tight engagement of the pipe, nipple or male threads. When gaging NPT threaded parts, thread the marked side on first. Parts being checked are generally acceptable when they come flush to end of ring to plus (+) or minus (-) one turn.

NPTF L1 plug is used to check an internal threaded hole. The NPTF L1 plug inspects the functional size or hand tight engagement of couplings or an internal thread. NPTF gages are used to inspect pipe threads that are used in Dryseal applications. NPTF gages are manufactured per ANSI/ASME B1.20.5Screw the L1 plug into the fitting (hand tighten). This classifies the thread as to “Maximum”, “Basic”, or “Minimum”. NPTF (Dryseal) and ANPT (Aeronautical) thread tolerances are more closely controlled requiring an L3 gage as well as an L1.

NPTF L3 plug is used to check an internal threaded hole. The NPTF L3 plug inspects the wrench engagement and taper of couplings or internal threads and is used in conjunction or relationship with the NPTF L1. NPTF gages are used to inspect pipe threads that are used in Dryseal applications Screw the L3 plug into the fitting (hand tighten). The gage must match the classification of the L1 plug within +/- 1/2 turns. NPTF (Dryseal) and ANPT (Aeronautical) thread tolerances are more closely controlled requiring an L3 gage as well as an L1.

NPTF 6 step plug is used in tapered threaded holes. The NPTF 6 step plug inspects the crest truncation or profile of the internal threads and is used in conjunction with L1 plug. NPTF gages are used to inspect pipe threads that are used in Dryseal applications. Insert the 6-step (crest check) plug into the fitting. When the L1 plug is at the maximum notch, the 6-step gage must go between “MX” and “MXT” notch. When the L1 plug is at the Basic Notch, the 6-Step gage must go between “B” and “BT” notch. When the L1 plug is at minimum notch, the 6-Step gage must go between the “MN” and “MNT” notch.

NPTF L1 ring gages are used to check external threaded parts. NPTF L1 ring gages inspect the functional size or hand tight engagement of the pipe, nipple or male threads. NPTF gages are used to inspect pipe threads that are used in Dryseal applications NPTF (Dryseal) and ANPT (Aeronautical) thread tolerances are more closely controlled requiring an L2 thick ring gage as well as the L1 ring.

NPTF L2 ring inspects the wrench engagement threads of a coupling and taper of the external threads and to be used in conjunction or relationship with the NPTF L1. NPTF gages are used to inspect pipe threads that are used in Dryseal applications NPTF (Dryseal) and ANPT (Aeronautical) thread tolerances are more closely controlled requiring an L2 thick ring gage as well as the L1 ring.

NPTF 6 step ring gages are used to check external threaded parts. NPTF 6 step ring gages check the crest truncation or profile of the external threads and are used in conjunction or relationship with the L1 ring. NPTF gages are used to inspect pipe threads that are used in Dryseal applications NPTF (Dryseal) and ANPT (Aeronautical) thread tolerances are more closely controlled requiring an L2 thick ring gage as well as the L1 ring.

WESTport Gage offers a complete line of taper pipe gages including special and custom designs. NPT general purpose pipe thread plug and ring gages are manufactured per ANSI/ASME B1.20.1. Threads are within the permissible limits of the tolerance when the gaging notch of the plug or gaging face of the ring is plus or minus one turn from being flush with the end of the thread.

NPTF gages are used to inspect pipe threads that are used in dryseal applications. NPTF gages are manufactured per ANSI/ASME B1.20.5. Standard practice for gaging NPTF threads calls for using 2 or 3 gages used in conjunction with each other. The standard calls out class 1 and class 2 NPTF threads. Class 1 signifies that specific inspection of root and crest truncation is not required, while class 2 signifies that such is required. Other taper pipe thread gages include PTF SAE Short and NGT sizes.

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