Leader Corporation offers a complete line of tapered 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 in coordination 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 tapered pipe thread gages include PTF SAE Short and NGT sizes.