Toilet      06/17/2019

Pipe thread sizes. designation. guests. Designation and dimensions of pipe thread Pipe connection inch female g1

Pipe thread cylindrical, G (BSPP)

Pipe cylindrical thread used in cylindrical threaded connections, as well as in connections of an internal cylindrical thread with an external conical thread according to GOST 6211-81. based on carving BSW(English) British Standard Whitworth, common inch pipe threads, also known as Whitworth threads) and is compatible with B.S.P.(English) british standard pipe thread) and denoted BSPP.

  • GOST 6357-81. Basic norms of interchangeability. The thread is pipe cylindrical.
  • ISO R228
  • EN 10226
  • DIN 259
  • BS2779
  • JIS B 0202

Thread parameters

Inch thread with a profile angle at the top of 55 °, the theoretical profile height H = 0.960491P.

Cut into pipes up to size 6", pipes over 6" are welded.

Symbol according to GOST 6357-81: letter G, the numerical value of the nominal diameter of the pipe in inches , the accuracy class of the average diameter ( A, IN), and letters LH for left hand thread. For example, a thread with a nominal diameter of 1 1/8, accuracy class A- designated as: G 1 1/8-A.

According to GOST 6357-81 Cylindrical pipe thread. Basic standards of interchangeability There are four values ​​for the thread pitch of a cylindrical pipe.

Table 2. Cylindrical pipe thread size designation (G), pitches and nominal values ​​​​of the outer, middle and inner thread diameters, mm
Thread size designation P step Thread diameters
Row 1 Row 2 d=D d2=D2 d1=D1
1/16" 0,907 7,723 7,142 6,561
1/8" 9,728 9,147 8,566
1/4" 1,337 13,157 12,301 11,445
3/8" 16,662 15,806 14,950
1/2" 1,814 20,955 19,793 18,631
5/8" 22,911 21,749 20,587
3/4" 26,441 25,279 24,117
7/8" 30,201 29.0З9 27,877
1" 2,309 33,249 31,770 30,291
1⅛" 37,897 36,418 34,939
1¼" 41,910 40,431 38,952
1⅜" 44,323 42,844 41,365
1½" 47,803 46,324 44,845
1¾" 53,746 52,267 50,788
2" 59,614 58,135 56,656
2¼" 65,710 64,231
2½" 75,184 73,705 72,226
2¾" 81,534 80,055 78,576
3" 87,884 86,405 84,926
3¼" 93,980 92,501 91,022
3½" 100,330 98,851 97,372
3¾" 106,680 105,201 103,722
4" 113,030 111,551 110,072
4½" 125,730 124,251 122,772
5" 138,430 136,951 135,472
5½" 151,130 148,651 148,172
6" 163,830 162,351 160,872
where d is the outer diameter of the outer thread (pipe); D - outer diameter of the internal thread (coupling); D 1 - internal diameter of the internal thread; d 1 - inner diameter of the external thread; D 2 - the average diameter of the internal thread; d 2 - the average diameter of the external thread. When choosing a pipe thread size first row should be preferred second.

The designation of the thread size corresponds to the inner diameter of the pipe according to one of the standards (en: Nominal Pipe Size).

Conical pipe thread, R (BSPT)

Pipe conical thread used in conical threaded connections, as well as in connections with an external conical thread from an internal cylindrical thread according to GOST 6357-81. based on carving BSW(English) British Standard Whitworth) and thread compatible B.S.P.(English) british standard pipe tapered thread ), called BSPT(sealing is achieved by crushing the thread in place threaded connection when screwing in the fitting).

  • GOST 6211-81. Basic norms of interchangeability. The thread is pipe conical.
  • ISO R7
  • DIN 2999
  • BS21
  • JIS B 0203

Thread parameters

Inch thread with taper 1:16 (taper angle φ=3°34’48"). Profile angle at apex 55°.

Symbol: letter R for external thread and Rc for internal (GOST 6211-81. Basic standards of interchangeability. Tapered pipe thread.), numerical value of the nominal thread diameter in inches (inch), letters LH for left-hand thread. For example, a thread with a nominal diameter of 1 1/4 is designated as R 1 1/4.

Thread size designation, pitches and nominal values ​​of the outer, middle and inner diameters of the pipe conical thread (R), mm
Size designation
carving		 Step P Thread length
working Outer
d=D		 Average
d2=D2		 Interior
d1=D1
1/16" 0,907 6,5 4,0 7,723 7,142 6,561
1/8" 6,5 4,0 9,728 9,147 8,566
1/4" 1,337 9,7 6,0 13,157 12,301 11,445
3/8" 10,1 6,4 16,662 15,806 14,950
1/2" 1,814 13,2 8,2 20,955 19,793 18,631
3/4" 14,5 9,5 26,441 25,279 24,117
1" 2,309 16,8 10,4 33,249 31,770 30,291
1¼" 19,1 12,7 41,910 40,431 38,952
1½" 19,1 12,7 47,803 46,324 44,845
2" 23,4 15,9 59,614 58,135 56,565
2½" 26,7 17,5 75,184 73,705 72,226
3" 29,8 20,6 87,884 86,405 84,926
3½" 31,4 22,2 100,330 98,851 97,372
4" 35,8 25,4 113,030 111,551 110,072
5" 40,1 28,6 138,430 136,951 135,472
6" 40,1 28,6 163,830 162,351 160,872

Round thread for sanitary fittings, Kr

Round thread for sanitary fittings. The thread is used for spindles, valves, faucets, toilet and water taps.

Thread NPSM (National pipe thread)

Thread inch pipe cylindrical (eng. NPSM) - American thread standard according to ANSI /ASME B1.20.1. The standard provides thread sizes from 1/16" to 24" for ANSI/ASME B36.10M , BS 1600 , BS EN 10255 and ISO 65 pipe.

Thread size designation NP, pitches and nominal values ​​of outer, middle and inner thread diameters, mm
Size designation
carving		 Threads per inch Thread length Thread diameter in base plane
working From the end of the pipe to the main plane Outer
d=D		 Average
d2=D2		 Interior
d1=D1
1/16" 27 6,5 4,064 7,895 7,142 6,389
1/8" 7,0 4,572 10,272 9,519 8,766
1/4" 18 9,5 5,080 13,572 12,443 11,314
3/8" 10,5 6,096 17,055 15,926 14,797
1/2" 14 13,5 8,128 21,223 19,772 18,321
3/4" 14,0 8,611 26,568 25,117 23,666
1" 11½ 17,5 10,160 33,228 31,461 29,694
1¼" 18,0 10,668 41,985 40,218 38,451
1½" 18,5 10,668 48,054 46,287 44,520
2" 19,0 11,074 60,092 58,325 56,558
2½" 8 72,699
3" 88,608
3½" 101,316
4" 113,973
5" 141,300
6" 168,275
8" 219,075
10" 273,050
12" 323,850

Thread NPT (National pipe thread)

Thread inch conical pipe (eng. NPT) - American standard for threads with a taper of 1:16 (taper angle φ \u003d 3 ° 34’48 ") or cylindrical (Eng. NPS) thread on ANSI/ASME B1.20.1. Thread NPT corresponds to GOST 6111-52. The thread is conical inch with a profile angle of 60 degrees. There is also an NPTF thread - sealing occurs due to thread crushing. The standard provides thread sizes from 1/16" to 24" for pipes according to standards ANSI/ASME B36.10M, BS 1600, BS EN 10255 And ISO 65.

The profile angle at the top is 60°, the theoretical profile height is Н=0.866025Р.

NPT thread size designation, pitches and nominal values ​​of outer, middle and inner thread diameters, mm
Size designation
carving		 Threads per inch Thread length Thread diameter in base plane
working From the end of the pipe to the main plane Outer
d=D		 Average
d2=D2		 Interior
d1=D1
1/16" 27 6,5 4,064 7,895 7,142 6,389
1/8" 7,0 4,572 10,272 9,519 8,766
1/4" 18 9,5 5,080 13,572 12,443 11,314
3/8" 10,5 6,096 17,055 15,926 14,797
1/2" 14 13,5 8,128 21,223 19,772 18,321
3/4" 14,0 8,611 26,568 25,117 23,666
1" 11½ 17,5 10,160 33,228 31,461 29,694
1¼" 18,0 10,668 41,985 40,218 38,451
1½" 18,5 10,668 48,054 46,287 44,520
2" 19,0 11,074 60,092 58,325 56,558
2½" 8 72,699
3" 88,608
3½" 101,316
4" 113,973
5" 141,300
6" 168,275
8" 219,075
10" 273,050
12" 323,850

Notes

see also

Inch thread is used primarily to create pipe connections: it is applied both to the pipes themselves and to the metal and plastic fittings necessary for the installation of pipe lines for various purposes. The main parameters and characteristics of the threaded elements of such connections are regulated by the relevant GOST, giving tables of sizes for inch threads, which specialists are guided by.

Main settings

The normative document, which specifies the requirements for the dimensions of a cylindrical inch thread, is GOST 6111-52. Like any other, inch thread is characterized by two main parameters: pitch and diameter. The latter usually means:

  • outer diameter, measured between the upper points of the threaded ridges located on opposite sides of the pipe;
  • internal diameter as a value characterizing the distance from one lowest point of the cavity between the threaded ridges to another, also located on opposite sides of the pipe.

Knowing the outer and inner diameters of an inch thread, you can easily calculate the height of its profile. To calculate this size, it is enough to determine the difference between such diameters.

The second important parameter - step - characterizes the distance at which two adjacent ridges or two adjacent depressions are located from each other. Throughout the entire section of the product on which the pipe thread is made, its pitch does not change and has the same value. If such an important requirement is not met, it will simply be inoperative, it will not be possible to pick up the second element of the created connection to it.

You can familiarize yourself with the provisions of GOST regarding inch threads by downloading the document in pdf format from the link below.

Table of sizes of inch and metric threads

Learn how metric threads relate to various types inch threads, you can use the data from the table below.

Similar sizes of metric and various varieties of inch threads in the range of approximately Ø8-64mm

Differences from metric thread

By their own outward signs and characteristics, metric and inch threads do not have many differences, the most significant of which include:

  • threaded comb profile shape;
  • the procedure for calculating the diameter and pitch.

When comparing the shapes of threaded ridges, you can see that in inch threads such elements are sharper than in metric ones. If we talk about the exact dimensions, then the angle at the top of the crest of an inch thread is 55 °.

The parameters of metric and inch threads are characterized by different units of measurement. So, the diameter and pitch of the first are measured in millimeters, and the second, respectively, in inches. However, it should be borne in mind that in relation to an inch thread, not the generally accepted one (2.54 cm), but a special pipe inch, equal to 3.324 cm, is used. Thus, if, for example, its diameter is ¾ inch, then in terms of millimeters, it will correspond to a value of 25.

To find out the main parameters of an inch thread of any size, which is fixed by GOST, just look at a special table. In the tables containing the sizes of inch threads, both integer and fractional values ​​\u200b\u200bare given. It should be borne in mind that the pitch in such tables is given in the number of cut grooves (threads) contained in one inch of the length of the product.

To check whether the pitch of the thread that has already been made corresponds to the dimensions specified by GOST, this parameter must be measured. For such measurements, carried out for both metric and inch threads according to one algorithm, standard tools are used - a comb, gauge, mechanical gauge, etc.

The easiest way to measure the pitch of an inch pipe thread is by using the following method:

  • As the simplest template, a coupling or fitting is used, the parameters of the internal thread of which exactly correspond to the requirements given by GOST.
  • The bolt, the parameters of the external thread of which must be measured, is screwed into a coupling or fitting.
  • In the event that the bolt has formed a tight threaded connection with a coupling or fitting, then the diameter and pitch of the thread that is applied to its surface exactly correspond to the parameters of the template used.

If the bolt is not screwed into the template or is screwed, but creates a loose connection with it, then such measurements should be taken using a different coupling or other fitting. An internal pipe thread is also measured using a similar technique, only a product with an external thread is used as a template in such cases.

You can determine the required dimensions using a thread gauge, which is a plate with notches, the shape and other characteristics of which exactly match the parameters of the thread with certain step. Such a plate, acting as a template, is simply applied to the thread being checked with its serrated part. The fact that the thread on the element under test corresponds to the required parameters will be indicated by the tight fit of the serrated part of the plate to its profile.

In order to measure the size of the outside diameter of an inch or metric thread, you can use a regular caliper or micrometer.

Slicing technologies

Cylindrical pipe thread, which belongs to the inch type (both internal and external), can be cut manually or mechanically.

Thread cutting by hand

Threading with hand tool, which is used as a tap (for internal) or a die (for external), is performed in several steps.

  1. The pipe being processed is clamped in a vice, and the tool used is fixed in a wrench (tap) or in a die holder (die).
  2. The die is put on the end of the pipe, and the tap is inserted into inner part last.
  3. The tool used is screwed into the pipe or screwed onto its end by rotating the knob or die holder.
  4. To make the result cleaner and more accurate, you can repeat the cutting procedure several times.

Thread cutting on a lathe

Mechanically, pipe threads are cut according to the following algorithm:

  1. The pipe being processed is clamped in the machine chuck, on the support of which the thread-cutting tool is fixed.
  2. At the end of the pipe, using a cutter, they chamfer, after which they adjust the speed of movement of the caliper.
  3. After bringing the cutter to the surface of the pipe on the machine, the threaded feed is turned on.

It should be borne in mind that the inch thread is cut mechanically using lathe only on tubular products, the thickness and rigidity of which allow this. Making pipe inch threads mechanically allows you to get a high-quality result, but the use of such technology requires the turner to have appropriate qualifications and the presence of certain skills.

Accuracy classes and marking rules

A thread related to the inch type, as indicated by GOST, can correspond to one of three accuracy classes - 1, 2 and 3. Next to the number indicating the accuracy class, put the letters "A" (external) or "B" (internal). The full designations of the thread accuracy classes, depending on its type, look like 1A, 2A and 3A (for external) and 1B, 2B and 3B (for internal). It should be borne in mind that the 1st class corresponds to the coarsest threads, and the 3rd - the most accurate, the dimensions of which are subject to very stringent requirements.

Parameters such as the quality of the pipe thread, its compliance with the axis of the pipe play a key role in the installation of plumbing and heating systems. In some cases, do-it-yourself cutting with a die is used. It must be said that this work difficult, inefficient and time consuming. It is better to cut with a cutter using a lathe.

General thread information

Pipe threads are protrusions and cavities with the same section, evenly spaced on a cylindrical or conical surface (for example, nuts, screws, bolts). They are located along a helix with the same pitch.

In everyday life, parts with a cylindrical thread are usually used. However, there are other types as well. There are two defining parameters for metric threads: pitch and diameter. An inch thread is so named because its defining characteristics are the diameter, expressed in inches or fractions of an inch. Also an important parameter in this case is the number of turns located on the length of an inch. The size in inches indicates the clearance in the element, while the outer diameter of the part is large.

Pipe thread table according to GOST

Important: One inch equals 2.54 cm. There is also another unit of measurement - a pipe inch. It is equal to 33, 249 mm. What is this inch unit of measurement? They brought it out like this: a value characterizing the thickness of both walls of the pipe was added to the value in inches.

There are two types of pipes, the parameter for the classification of which is the pipe inch:

  • Product with an outer diameter of 33, 249 mm;
  • Product with an outer diameter of 21.25 mm.

An inch thread is a set of parameters necessary for connecting pipes, fittings and other parts. From metric, among other things, it differs in such features as:

  • Pointed ridges-hollows;
  • Rounded hilltops.

Dimensions

IN living conditions most often you can find pipes with the following parameters and dimensions determined by GOST:

  • Thread 14 threads per 1 inch. In this case, the pitch is 1.814 mm. The diameter can be ½ or ¾;
  • 11 threads per 1 inch. In this case, the pitch is 2.309 mm. The diameter can be 1, 1 ¼, 1 1/2, 2.

Inch threads are made only on pipelines whose dimensions do not exceed 6″. If the parameters of the pipe are greater, it is mounted in the system by means of welding work. Its designations according to GOST: G (the value of the passage of elements, indicated in inches), A, B (the degree of accuracy of diameters).

The selection of inch threaded pipes requires knowledge of many parameters. For this purpose, there are a number of tables that list all the important values. There are tables from which you can find out the steps and their relationship with threads per inch. So you can quickly and easily get acquainted with all necessary information. You can find all the necessary tables on our website. They will help not only amateurs, but also professionals in working with pipes.


It would seem that in the pipes of the complex? Connect and twist ... But, if you are not a plumber or an engineer with a specialized education, then questions will definitely arise for answers to which you will have to go where your eyes look. And they most likely look first on the Internet)

Earlier we talked about diameters metal pipes in this material. Today we will try to clarify the threaded connections of pipes for various purposes. We have tried not to clutter up the article with definitions. Basic terminology contains GOST 11708-82 which everyone can see for themselves.

Pipe cylindrical thread. GOST 6357 - 81

Direction: Left

Accuracy class: Class A (increased), Class B (normal)

Why in inches?

The inch size came to us from Western colleagues, since the requirements of the current in the post-Soviet space GOST and formulated on the basis of the thread BSW(British Standard Whitworth or Whitworth thread). Joseph Whitworth (1803 - 1887), a design engineer and inventor back in 1841, demonstrated the screw profile of the same name for detachable connections and positioned it as a universal, reliable and convenient standard.

This type of thread is used both in the pipes themselves and in the elements of pipe connections: locknuts, couplings, elbows, tees ( see picture above). In the section of the profile, we see an isosceles triangle with an angle of 55 degrees and roundings at the tops and bottoms of the contour, which are made for high tightness of the connection.

Threading is carried out on sizes up to 6”. All pipes bigger size to secure the connection and prevent rupture, they are fixed by welding.

Symbol in the international standard

International: G

Japan: PF

UK: BSPP

The letter G is indicated and the bore diameter (inner Ø) of the pipe in inches. The outer diameter of the thread itself is not present in the designation.

Example:

G 1/2- a pipe thread cylindrical external, internal Ø of a pipe 1/2 "". The outer diameter of the pipe will be 20.995 mm, the number of steps for a length of 25.4 mm will be 14.

The accuracy class (A, B) and the direction of the turns (LH) can also be indicated.

For example:

G 1 ½ - B- cylindrical pipe thread, internal Ø 1 ½ inches, accuracy class B.

G1 ½ LH-B- cylindrical pipe thread, internal Ø 1 ½ inches, accuracy class B, left.

The make-up length is indicated last in mm: G 1 ½ -B-40.

For an internal cylindrical pipe thread, only the Ø of the pipe for which the hole is intended will be indicated.

Parallel pipe thread size table

Thread size

Thread pitch, mm

Threads per inch

Thread diameters

How to determine the pitch of an inch thread

I give you a picture from the English-speaking Internet, which clearly demonstrates the technique. Pipe threads are characterized not by the size between the tops of the profile, but by the number of turns per 1 inch along the axis of the thread. To help the usual tape measure or ruler. We apply, measure one inch (25.4 mm) and visually count the number of steps.

In the picture with an example ( see above) threads - from English it is literally "thread threads". In this case, there are 18 of them. one inch.

It's even easier if you have an inch thread gauge lying around in your toolbox. It is very convenient to carry out measurements, but it must be remembered that inch threads may differ in the apex angle of 55 ° and 60 °.

Tapered pipe threads

drawing pipe taper threads

Tapered pipe thread GOST 6211-81 (1st standard size)

Parameter unit: Inch

Corresponds to the rounded profile of a cylindrical pipe thread with an angle of 55°. Cm. top part (I) of the three-dimensional image "picture of pipe taper threads".

Symbol

International: R

Japan: PT

UK: BSPT

The letter R and the nominal diameter Dy are indicated. The designation R means appearance threads, Rc internal, Rp internal cylindrical. By analogy with cylindrical pipe threads, LH is used for left-hand threads.

Examples:

R1½- external pipe conical thread, nominal diameter Dy = 1 ½ inches.

R1 ½ LH- external pipe taper thread, nominal diameter Dy = 1 ½ inches, left hand.

Conical inch thread GOST 6111 - 52 (2nd standard size)

Parameter unit: Inch

Has a profile angle of 60°. Cm. lower part (II) of the three-dimensional image "picture of pipe conical threads". It is used in pipelines (fuel, water, air) of machines and machine tools with relatively low pressure. The use of this type of connection assumes tightness and thread locking without additional special means(linen threads, yarn with red lead).

Symbol

Example: K ½ GOST 6111 - 52

It stands for: inch conical thread with an outer and inner diameter in the main plane approximately equal to the outer and inner Ø of a cylindrical pipe thread G ½

Table of the main parameters of the conical inch thread

Thread size designation (d, inches) Number of threads per 1" n Thread pitch S, mm Thread length, mm External thread diameter in the main plane d, mm
Working l1 From the end of the pipe to the main plane l2
1/16 27 0,941 6,5 4,064 7,895
1/8 27 0,941 7,0 4,572 10,272
1/4 18 1,411 9,5 5,080 13,572
3/8 18 1,411 10,5 6,096 17,055
1/2 14 1,814 13,5 8,128 21 793
3/4 14 1,814 14,0 8,611 26,568
1 11 1/2 2,209 17,5 10,160 33,228
1 1/4 11 1/2 2,209 18,0 10,668 41,985
1 1/2 11 1/2 2,209 18,5 10,668 48,054
2 11 1/2 2,209 19,0 11,074 60,092

Metric taper thread. GOST 25229 - 82

Parameter unit: mm

Manufactured on surfaces with a taper of 1:16

It is used when connecting pipelines. The angle at the top of the coil is 60°. The main plane is offset relative to the end ( see pic above).

Symbol

The letters MK are followed by an indication of the diameter in the main plane and the thread pitch in mm: MK 30x2

Metric Taper Thread Size Chart

Thread diameter d for a row P step Thread diameter in base plane
1 2 d=D d2=D2 d1=D1 l l1 l2
6 --- 1 6,000 5,350 4,917 8 2,5 3
8 --- 8,000 7,350 6,917
10 --- 10,000 9,350 8,917
12 --- 1,5 12,000 11,026 10,376 11 3,5 4
--- 14 14,000 13,026 12,376
16 --- 16,000 15,026 14,376
--- 18 18,000 17,026 16,376
20 --- 20,000 19,026 18,376
--- 22 22,000 21,026 20,376
24 --- 24,000 23,026 22,376
--- 27 2 27,000 25,701 24,835 16 5 6
30 --- 30,000 28,701 27,835
--- 33 33,000 31,701 30,835
36 --- 36,000 34,701 33,835

Characteristics of cylindrical pipe / inch threads relative to metric

The main characteristics of "inch" and "pipe" cylindrical threads in relation to the "metric" thread for the main dimensions.

Nominal thread diameter in dm

Inch thread

Pipe thread

outer diameter, in mm

number of threads per 1"

outer diameter, in mm

number of threads per 1"
Where did the Romanov dynasty come from? Previous post

Where did the Romanov dynasty come from?

What to do if you get sick on an airplane? Next post

What to do if you get sick on an airplane?

Categories
The last notes
Pages

2023 Plumbing, sewerage, water supply — syko.ru