图片
产品搜索
产品分类
斯托茨量规厂│Acme螺纹规 GSG美国进口管螺纹量规 GSG石油螺纹规│API量规 GSG美制螺纹规│美标螺纹规 GSG美国精密量规│进口量仪 GSG螺纹指示规│螺纹量仪 GSG美国倒角量规│锪孔量规 海克斯康(Hexagon)测量仪器 苏州甪直三丰Mitutoyo量具 昆山德国Fischer菲希尔仪器 张家港英国易高Elcometer 江阴美国GE超声波探伤仪 无锡奥林巴斯超声波探伤仪 吴江英国GBIS超声波探头 太仓Spectronics无损检测 常熟Bruker布鲁克光谱仪 美国赛普斯SCIAPS光谱仪 镇江美国磁通Magnaflux Western Instrument仪器 嘉兴南通友联无损检测仪器 绍兴G.A.L. Gage焊接量规 宁波瑞士Maurer Magnetic 苏州标样│无损探伤试块 盐城建湖BAQ GmbH硬度计 吴江测高仪│粗糙度仪│量具 金湖SIC MARKING西刻打标机 Clark硬度计│Sun-Tec硬度块 日本future-tech硬度计 美国King便携式布氏硬度计 美国Rex Gauge邵氏硬度计 进口Ames便携式洛氏硬度计 美国Hemco螺纹规中国总代理 PMC Lone Star石油螺纹量规 Vermont螺纹规│VTG螺纹规 GageAssembly螺纹规代理商 英国Threadmaster进口螺纹规 美国Westport螺纹规│硬度块 Threadcheck螺纹规│三线规 美国Mueller Gage沟槽量仪 德国Kroeplin内外径卡规 美国环球Universal Punch 东莞DULIANG光学检测仪器 德国Schwenk进口内径量仪 宝石石油量规│API石油规 美国Allen Gauge单项仪 美国Fowler High Precision Swiss Precision Instruments
NPT Taper Plug and Ring Gauges-Technical Specifications
作者:管理员    发布于:2018-02-04 09:36:10    文字:【】【】【
摘要:Gauges for testing threads to American National Standard ANSI/ASME B.1.20.1 - 1983.

NPT Taper Plug and Ring Gauges

Gauges for testing threads to American National Standard ANSI/ASME B.1.20.1 - 1983.

This standard covers dimensions and gauging of pipe threads for general purpose applications.

The main types of threads designated are NPT, NPSC and NPSM.

The significance of each letter is as follows:

N = National (American) Standard
P = Pipe
T = Taper
C = Coupling
S = Straight
M = Mechanical

NPT Threads

Threaded fittings made to this standard consist of an external taper and an internal taper to form a joint having general purpose applications. These threads are intended to be made up wrench-tight, with a sealant whenever a pressure-tight joint is required.

The taper of the thread is 1:16 on diameter, normal to the axis. The pipe fittings range in size from 1/16 inch to 24 inch.

Provision is made for two types of gauge.

Master gauges: used to check working gauges.

Working gauges: used to check product threads during and after manufacture.

A set of master gauges

consists of a taper plug with a gauging notch located at L1 distance from the small end. The ring gauge has an overall length equal to the L1 dimension. This ring is fitted to its mating plug seating flush at the gauging notch. It should be understood that only a specifically matched set of masters (L1 plug and L1 ring) can be expected to assemble together within a stand-off tolerance of +/-0.002 inch as specified.

A set of working gauges

consists of a taper plug gauge having a basic step at L1 distance from the small end, and a taper ring having an overall length equal to the L1 dimension. Plug and ring gauges can be supplied with limit steps to indicate the minimum and maximum diametral condition of the product. These gauges are known as MIN/MAX. The basic steps can be included or omitted as requested.

The L1 dimension is the axial distance from the small end of the pipe to the plane of handtight engagement.


These are parallel internal threads only in pipe couplings, and have the same thread form as the NPT thread. They are used to form pressure tight joints when assembled with NPT external threads, and made up wrench-tight with a sealant.
NPSC Threads

The threads range in size from 1/8 inch to 4 inch.

Go/No Go parallel plug gauges can be supplied to test the diametral limits of these threads, although the standard states that NPT taper plug gauges should be used to test the internal product thread where the mating external threads are tapered and a pressure tight joint is required.

NPSM Threads

These are parallel threads, internal and external. The basic thread details correspond with NPT threads at the plane of handtight engagement.

Free fitting mechanical joints are used for special applications where there are no internal pressures. NPSM threads range in size from 1.8 inch to 6 inch.

NPT Taper Plug
  • Notation
  • H = 0.866025p = height of 60deg. sharp V thread
  • h = 0.800000p = height of thread on product
  • p = 1/n = pitch (measured parallel to axis)
  • n = number of threads per inch
  • a = 30deg. = thread flank angle
  • ß = 1deg. 47 min. = thread taper angle for 1/16 taper
  • fc = depth of truncation at crest
  • fr = depth of truncation at root
  • Fc = width of flat at crest
  • Fr = width of flat at root
QQ客服
点击这里给我发消息