ASME B1.20.2M:2006 pdf free download

ASME B1.20.2M:2006 pdf free download.Pipe Threads, 60 deg, General Purpose.
ASME B1.20.2M specifies the designations, dimensions, and tolerances and establishes a verification system for 60 deg included angle pipe threads. It is applicable for general purpose pipe and fitting connections. Where pressure-tight joints are required, it is intended that taper pipe threads conforming to this Standard be made up wrench-tight with a sealant. To prevent galling on certain piping materials such as stainless steel, the sealant should contain a lubricant.
Internal parallel (straight) pipe threads, series NPSC, are used with external taper pipe threads, series NPT. Internal taper pipe threads, series NI’T, are used with external taper pipe threads, series NPT.
2 REFERENCE AND SYMBOLS
2.1 Reference Standard
The following publication is referenced in this Standard. The latest edition shall apply.
ASME B1.20.1, Pipe Threads, General Purpose (Inch)
Publisher: The American Society of Mechanical Engineers (ASME), Three Park Avenue, Ness’ York, NY 10016-5900; Order Department: 22 Law Drive, P.O. Box 2300, Fairfield, NJ 07007-2300
2.2 Symbols
The following symbols are used (see Fig. I):
D = outside diameter of pipe
E0 basic pitch diameter at small end of external thread (or end of pipe)
E1 = basic pitch diameter at plane of hand-tight engagement length (L1), external thread, large end of internal thread
E2 = basic pitch diameter at plane of effective thread length (L2), external thread
E3 = basic pitch diameter at plane of wrench-tight engagement
E — basic pitch diameter at £5
= basic minor diameter at small end of external thread (or end of pipe)
L1 = length of hand-tight engagement between internal and external threads
L2 = length of effective thread, external thread
L3 = length of thread beyond L1 allowing wrench-tight engagement, internal thread;
6.2.2 Working Gauges. Each set of working gauges consists of an L1 taper-threaded ring gauge and an L1 taper-threaded plug gauge and is used for checking the product. These gauges are made of hardened steel or equivalent material to dimensions given in Table 5 (see para. 6.3.2 for tolerance). In locating the basic notch of the plug gauge, the plane of the notch should intersect the crest of the thread.
6.3 Gauge Tolerances
In the manufacture of gauges, variations from basic dimensions are unavoidable. Furthermore, gauges will wear in use. In order to fix the maximum allowable variations of gauges, tolerances have been established. See Table 6 and para. 6.3.2.
6.3.1 Master Gauge Tolerances. The set of master gauges should be made to the basic dimensions as accurately as possible, but in no case shall the cumulative variation exceed one-half of the total cumulative toleranceinColumns l3and l4ofTable6. Each mastergauge should be accompanied by a record of the measurement of all elements of the thread and the standoff of master plug to master ring (large end of ring gauge to basic notch of plug gauge).
6.3.2 Working Gauge Tolerance. All gauges applied to the product thread, whether in manufacture or inspection, are designated as working gauges. All working gauges should be made to the basic dimensions specified in Table 7 and within tolerances specified in Table 6. The maximum wear on a working gauge shall not be more than the equivalent of one-quarter turn from its original dimensions, as determined by its master gauge.
6.4 Relation of Lead and Angle Variations to Pitch Diameter Tolerance of Gauges
When it is necessary to compute from measurements the decimal part of a turn that a gauge varies from the basic dimensions, Tables 7 and 8 should be used. Table 7 gives the correction in diameter for lead variations and Table H gives the correction in diameter for angle variations. These corrections are always added to the pitch diameter in the case of external threads and subtracted in the case of internal threads regardless of whether the lead or angle variations are plus or minus.
The diameter equivalent for lead and angle variations plus the pitch diameter variation multiplied by 16 gives the longitudinal variation from basic at the gauging notch. This longitudinal variation divided by the pitch equals the decimal part of a turn that the gauge varies from basic at the gauging notch.