Parallel pipe threads are mainly used for pipe connections, pipe fittings and fittings. This thread covers diameters from 1/16" to 6" with threads per 1" from 28 to 11.

The nominal diameter of a pipe thread is conditionally related to the inner diameter of the pipe. According to the ratio of pitches and diameters, the pipe thread is a crushed inch thread according to OST 1260. Therefore, pipe thread at one time, before the standardization of fine metric threads, was used not only for pipe connections, but also for fasteners, when there was a need to make a thread with a relatively small steps, with large diameters. Pipe thread is a pan-European standard for pipes and pipe connections.

PIPE THREAD DIMENSIONS
(GOST 6357-81)

The standard applies to cylindrical pipe threads used in cylindrical threaded connections, as well as in internal connections. cylindrical thread with external conical thread according to GOST 6211-81.

Tolerances (according to GOST 6357-81) of the average thread diameter are set in two accuracy classes - A and B. The tolerances of the average thread diameter are total. Tolerances of diameters d 1 and D are not established.

dimensions, mm

MAKE-UP LENGTHS according to GOST 6357-81

Make-up lengths are divided into two groups: normal N and long L.

dimensions, mm

The symbol for the left thread is supplemented by the letters LH.

Examples of thread designation of accuracy class A:

G 1 1/2-A
left-hand thread accuracy class B:

G 1 1/2 LH-B

Make-up length N is not indicated in the thread designation.
Make-up length L is indicated in millimeters.

G 1 1/2 LH-B-40

Landing is indicated by a fraction: in the numerator of which the designation of the accuracy class of the internal thread is indicated, and in the denominator - the designation of the accuracy class of the external thread.

G 1 1/2-A/A; G 1 1/2 LH-A/B

The connection of an internal cylindrical pipe thread of accuracy class A according to this standard with an external pipe conical thread according to GOST 6211-81 is designated as follows:

G/R 1 1/2 - A

P.S. At one time, the profile of cylindrical pipe threads (according to OST 266) extended to diameters up to 18 "with the number of threads per 1" from 28 to 8.

Related Documents:

- tapping holes
GOST 3469-91: Microscopes. Thread for lenses. Dimensions
GOST 4608-81: Metric thread. Interference landings
GOST 5359-77: Ocular thread for optical instruments. Profile and dimensions
GOST 6042-83: Round Edison thread. Profiles, dimensions and limit dimensions
GOST 6111-52: Conical inch thread with a profile angle of 60 degrees
GOST 6211-81: Conical pipe thread
GOST 6357-81: Cylindrical pipe thread
GOST 8762-75: Round thread with a diameter of 40 mm for gas masks and calibers for it. Main dimensions
GOST 9000-81: Metric thread for diameters less than 1 mm. Tolerances
GOST 9484-81: Trapezoidal thread. Profiles
GOST 9562-81: Trapezoidal single thread. Tolerances
GOST 9909-81: Conical thread of valves and cylinders for gases
GOST 10177-82: Thrust thread. Profile and main dimensions
GOST 11708-82: Thread. Terms and Definitions
GOST 11709-81: Metric thread for plastic parts
GOST 13535-87: Reinforced thrust thread 45 degrees
GOST 13536-68: Round thread for sanitary fittings. Profile, basic dimensions, tolerances
GOST 16093-2004: Metric thread. Tolerances. Landings with clearance
GOST 16967-81: Metric thread for instrumentation. Diameters and steps
GOST 24737-81: Trapezoidal single thread. Main dimensions
GOST 24739-81: Multi-start trapezoidal thread
GOST 25096-82: Thrust thread. Tolerances
GOST 25229-82: Metric conical thread
GOST 28487-90: Tapered tool joint thread for drill string elements. Profile. Dimensions. Tolerances

GOST 6211-81

Group G13

INTERSTATE STANDARD

Basic norms of interchangeability

THREAD PIPE CONICAL

Basic norms of interchangeability. pipe taper thread

Introduction date 1983-01-01

1. DEVELOPED AND INTRODUCED by the Ministry of Machine Tool and Tool Industry

2. APPROVED AND INTRODUCED BY Decree of the State Committee of the USSR for Standards dated December 30, 1981 N 5789

3. REPLACE GOST 6211-69

4. The standard fully complies with ST SEV 1159-78

5. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

6. RE-ISSUE


This standard applies to pipe taper threads with a taper of 1:16, used in tapered threaded connections, as well as in connections of external tapered threads with internal cylindrical threads with a profile according to GOST 6357 and establishes the profile, main dimensions and tolerances of the tapered thread, as well as the tolerances of the internal cylindrical pipe thread connected to an external conical thread.

1. PROFILE

1. PROFILE

1.1. The nominal profile of the pipe taper thread (external and internal) and the dimensions of its elements must correspond to those indicated in Fig. 1 and in Table 1.

Damn.1. Nominal profile of taper pipe thread (external and internal) and dimensions of its elements

Taper ; ; ; - outer diameter of the outer conical thread; - inner diameter of external conical thread; - the average diameter of the external conical thread; - outer diameter of the internal conical thread; - internal diameter of the internal conical thread; - the average diameter of the internal conical thread; - thread pitch; - cone angle; - slope angle; - the height of the original triangle; - working height of the profile; - the radius of rounding of the top and bottom of the thread; - cut tops and bottoms of the thread.

Table 1

Dimensions in mm

Note. The numerical values ​​of the steps are determined from the ratio with rounding to the third decimal place and are taken as the initial ones when calculating the main profile elements.

1.2. The dimensions of the profile elements of the internal cylindrical thread are in accordance with GOST 6357.

2. BASIC DIMENSIONS

2.1. The designation of the thread size, steps and nominal values ​​​​of the main dimensions of the conical (external and internal) threads must correspond to those indicated in Fig. 2 and in Table 2.

Damn.2. Thread size designation, pitches and nominal values ​​​​of the main dimensions of the conical (external and internal) threads

Working thread length; - the length of the external thread from the end face to the main plane

table 2

Dimensions in mm

Shorter thread lengths may be used.

2.2. Numerical values ​​​​of diameters and are calculated by the following formulas

The numerical values ​​of the diameter are established empirically.

2.3. The difference in actual dimensions must not be less than the difference in nominal dimensions and specified in Table 2.

2.4. The length of the internal tapered thread must be at least 0.8 (, where - in accordance with Table 3) *.
________________
* The text of the document corresponds to the original. - Database manufacturer's note.

Table 3

Dimensions in mm

Note. Limit deviations and do not apply to threads with lengths less than those indicated in Table 2.

2.5. The designation of thread sizes, pitches and nominal values ​​​​of the outer, middle and inner diameters of the internal cylindrical thread must correspond to those indicated in Fig. 3 and in Table 2.

Damn.3. Designation of thread sizes, pitches and nominal values ​​​​of the outer, middle and inner diameters of the internal cylindrical thread

2.6. The design of parts with internal threads (conical and cylindrical) must ensure that the external conical thread is screwed in to a depth of at least .

3. TOLERANCES

3.1. The axial displacement of the main plane of the external and internal threads (Fig. 4) relative to the nominal location should not exceed the values ​​\u200b\u200bspecified in Table 3.

Damn.4. Axial displacement of the main plane of external and internal threads

Note. In the main plane, the average diameter has a nominal value.


The displacement of the main plane is total, including deviations of the average diameter, pitch, angle of inclination of the side of the profile and the angle of the cone.

3.2. Limit deviations of the average diameter of the internal cylindrical thread must correspond to those indicated in Table 3.

3.3. It is allowed to connect an external conical thread with an internal cylindrical thread of accuracy class A according to GOST 6357.

4. NOTATION

4.1. The thread symbol should include: letters ( - for a tapered external thread, - for a tapered internal thread, - for a cylindrical internal thread) and a designation of the thread size.

The symbol for the left thread is supplemented with letters.

Thread convention examples:

- external pipe conical thread 1:

Female pipe taper thread 1:

Female cylindrical thread 1:

Left hand thread:

4.2. A threaded connection is indicated by a fraction, for example, or, in the numerator of which the letter designation of the internal thread is indicated, and in the denominator - the external thread, and the size of the thread.

Examples of symbols for threaded connections:

- pipe conical thread (internal and external):

Female straight pipe threads (to the tolerances of this International Standard) and male taper pipe threads:

Internal cylindrical pipe thread of accuracy class A according to GOST 6357 and external pipe conical thread:

APPENDIX (reference). MAXIMUM DEVIATIONS OF INDIVIDUAL THREAD PARAMETERS

APPLICATION
Reference

1. This appendix contains information on the limit deviations of individual thread parameters, which are initial in the design of a thread forming tool and the calculation of thread gauges and are not subject to mandatory control, unless otherwise stated.

2. Limit deviations of the cut of peaks and troughs (size), angle of inclination of the side of the profile, pitch and angle of the cone (difference in average diameters along the length) of the conical thread are shown in Fig. 1 and in the table.

Damn.1. Limit deviations of the cut of peaks and troughs, the angle of inclination of the lateral side of the profile, the pitch and the angle of the cone

es - upper deviation of the cut of the top and bottom of the external thread; ES - upper deviation of the cut of the top and bottom of the internal thread; ei - lower deviation of the cut of the top and bottom of the external thread; EI - lower deviation of the cut of the top and bottom of the internal thread; - tolerance of the angle of inclination of the side of the thread profile.

3. Limit deviations of the cut of peaks and troughs (size) of an internal cylindrical thread (Fig. 2) should not exceed:

- top cut +0.05 mm (ES=+0.05 mm, EI=0);

- recess cut ±0.025 mm (ES=+0.025 mm, EI=-0.025 mm)

Damn.2. Limit deviations of the cut of peaks and troughs of an internal cylindrical thread

Dimensions in mm

Note. The value refers to the distance between the threads. The actual deviation can be minus or plus sign.



Electronic text of the document
prepared by Kodeks JSC and verified against:
official publication
Inch and special threads: Sat. GOSTs. -
M.: IPK Standards Publishing House, 2003

BASIC DIMENSIONS
PIPE CONICAL THREAD
(GOST 6211-81)

This standard applies to taper pipe threads with taper 1: 16 . used in conical threaded connections, as well as in connections of external conical threads with internal cylindrical threads with a profile according to GOST 6357-81.

Taper 2tg(φ /2) = 1: 16;
φ = 3°34"48"; φ/2 = 1°47"24";
d and D are the outer diameters of the external and internal threads, respectively;
d 1 and D 1 are the internal diameters of the external and internal threads, respectively;
d 2 and D 2 are the average diameters of the external and internal threads, respectively;
P - thread pitch;
φ - cone angle; φ/2 - slope angle;
H is the height of the original triangle;
H 1 - working height of the profile;
R is the radius of rounding of the top and bottom of the thread;
C - cut tops and bottoms of the thread;
l 1- working thread length;
l 2- the length of the external thread from the end to the main plane.

dimensions, mm

SYMBOL

The thread symbol should include: letters (R - for a tapered external thread, R c - for a tapered internal thread, R p - for a cylindrical internal thread) and thread size designation:
external pipe conical thread - R 1 1/2
internal pipe taper thread - R with 1 1/2
female cylindrical thread - R p 1 1/2
left-hand thread - R 1 1/2LH, R c 1 1/2LH, R p 1 1/2LH.

A threaded connection is indicated by a fraction, for example Rc / R or Rp / R, in the numerator of which indicate the letter designation of the internal thread, and in the denominator - the external thread, and the size of the thread.
For example: R with /R 1 1/4LH.

TAPERED PIPE THREAD TOLERANCES
(GOST 6211-81)

dimensions, mm

Thread profile	Designation size carving	Offset thread base plane		Limit deviations diameter internal cylindrical carving
		±Δ 1 l 1	±Δ 2 l 2
	1/16"	0,9	1,1	±0.071
	1/8"
	1/4"	1,3	1,7	±0.104
	3/8"
	1/2"	1,8	2,3	±0.142
	3/4"
	1"	2,3	2,9	±0.180
	1 1/4"
	1 1/2"
	2"
	2 1/2"	3,5	3,5	±0.217
	3"
	3 1/2"
	4"
	5"
	6"
In the main plane, the average diameter has a nominal value.
Note. The limit deviation ±Δ 1 l 1 and ±Δ 2 l 2 does not apply to threads with lengths less than those indicated in the first table.

Shorter thread lengths may be used.

Actual size difference l 1 - l 2 must be at least the difference in nominal dimensions l 1 And l 2 indicated in the first table.

Related Documents:

GOST 3469-91: Microscopes. Thread for lenses. Dimensions
GOST 4608-81: Metric thread. Interference landings
GOST 5359-77: Ocular thread for optical instruments. Profile and dimensions
GOST 6042-83: Round Edison thread. Profiles, dimensions and limit dimensions
GOST 6111-52: Conical inch thread with a profile angle of 60 degrees
GOST 6211-81: Conical pipe thread
GOST 6357-81: Cylindrical pipe thread
GOST 8762-75: Round thread with a diameter of 40 mm for gas masks and calibers for it. Main dimensions
GOST 9000-81: Metric thread for diameters less than 1 mm. Tolerances
GOST 9484-81: Trapezoidal thread. Profiles
GOST 9562-81: Trapezoidal single thread. Tolerances
GOST 9909-81: Conical thread of valves and cylinders for gases
GOST 10177-82: Thrust thread. Profile and main dimensions
GOST 11708-82: Thread. Terms and Definitions
GOST 11709-81: Metric thread for plastic parts
GOST 13535-87: Reinforced thrust thread 45 degrees
GOST 13536-68: Round thread for sanitary fittings. Profile, basic dimensions, tolerances
GOST 16093-2004: Metric thread. Tolerances. Landings with clearance
GOST 16967-81: Metric thread for instrumentation. Diameters and steps
GOST 24737-81: Trapezoidal single thread. Main dimensions
GOST 24739-81: Multi-start trapezoidal thread
GOST 25096-82: Thrust thread. Tolerances
GOST 25229-82: Metric conical thread
GOST 28487-90: Tapered tool joint thread for drill string elements. Profile. Dimensions. Tolerances

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

We have already talked about the diameters of 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 larger pipes are fixed by welding to secure the connection and prevent rupture.

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

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 external thread, Rc internal, Rp internal cylindrical. By analogy with a cylindrical pipe thread, 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 implies 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

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

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.

Introduction date 01.01.83

This standard applies to pipe taper threads with a taper of 1:16, used in tapered threaded connections, as well as in connections of external tapered threads with internal cylindrical threads with a profile according to GOST 6357 and establishes the profile, main dimensions and tolerances of the tapered thread, as well as the tolerances of the internal cylindrical pipe thread connected to an external conical thread.

1. PROFILE

1.1. The nominal profile of the pipe taper thread (external and internal) and the dimensions of its elements must correspond to those indicated in Fig. 1 and in table. 1.

Table 1

Dimensions in mm

Note . The numerical values ​​of the steps are determined from the relation R = 25,4/z with rounding up to the 3rd decimal place and taken as the initial ones when calculating the main elements of the profile.

1.2. The dimensions of the profile elements of the internal cylindrical thread are in accordance with GOST 6357.

2. BASIC DIMENSIONS

2.1. The designation of the thread size, steps and nominal values ​​​​of the main dimensions of the conical (external and internal) threads must correspond to those indicated in Fig. 2 and in table. 2.

Shorter thread lengths may be used.

l 1 - working thread length; l 2 - the length of the external thread from the end to the main plane.

Crap. 2

Table 2

Dimensions in mm

2.2. Numerical values ​​of diameters d 2 and d 1 is calculated by the following formulas

d 2 = D 2 = d - 0,640327 P,(1)

d 1 = D 1 = d - 1,280654 P.(2)

Diameter Numerical Values d established empirically.

2.3. Actual size difference l 1 - l 2 must be at least the difference in nominal dimensions l 1 and l 2 indicated in table. 2.

2.4. The length of the internal tapered thread must be at least 0.8 ( l 1 - D 1 l 2), where D 1 l 2 - in accordance with the table. 3.

Table 3

Dimensions in mm

Note . Limit deviations± D 1 l 2 and ± D2 l 2 do not apply to threads with lengths less than those indicated in table. 2.

2.5. The designation of thread sizes, pitches and nominal values ​​​​of the outer, middle and inner diameters of the internal cylindrical thread must correspond to those indicated in Fig. 3 and in table. 2.

2.6. The design of parts with an internal thread (conical and cylindrical) must ensure that the external conical thread is screwed in to a depth of at least l 1 + D 1 l 2 .

3. TOLERANCES

3.1. Axial displacement of the main plane D 1 l 2 outdoor and D 2 l 2 internal threads (fig. 4) with respect to the nominal location should not exceed the values ​​\u200b\u200bspecified in table. 3.

The displacement of the main plane is total, including deviations of the average diameter, pitch, angle of inclination of the side of the profile and the angle of the cone.

3.2. Limit deviations of the average diameter of the internal cylindrical thread must correspond to those indicated in Table. 3.

Crap. 4

Note . In the main plane, the average diameter has a nominal value.

3.3. It is allowed to connect an external conical thread with an internal cylindrical thread of accuracy class A according to GOST 6357.

4. NOTATION

4.1. The thread symbol should include: letters ( R- for conical external thread, Rc - for conical internal thread, Rp- for a cylindrical internal thread) and thread size designation.

The symbol for the left thread is supplemented by letters LH.

Thread designation examples:

External pipe conical thread 1 1 / 2:

R 1 1 / 2

Female conical pipe thread 1 1 / 2:

Rc 1 1 / 2

Female cylindrical thread 1 1 / 2:

R P 1 1 / 2

Left hand thread:

R 1 1 / 2 LH;

Rc 1 1 / 2 LH;

R P 1 1 / 2 LH.

4.2. A threaded connection is indicated by a fraction, for example, or Rc/R, in the numerator of which the letter designation of the internal thread is indicated, and in the denominator - the external thread, and the size of the thread.

Designation examples threaded connection:

Pipe taper thread (internal and external);

Female straight pipe threads (to the tolerances of this International Standard) and male taper pipe threads:

Internal cylindrical pipe thread of accuracy class A according to GOST 6357 and external pipe conical thread:

APPLICATION
Reference

MAXIMUM DEVIATIONS OF INDIVIDUAL THREAD PARAMETERS

1. This appendix contains information on the limit deviations of individual thread parameters, which are initial in the design of a thread forming tool and the calculation of thread gauges and are not subject to mandatory control, unless otherwise stated.

2. Limit deviations of the cut of peaks and troughs (size WITH), angle of inclination of the lateral side of the profile, step R and cone angle j(difference of average diameters over the length l 2) conical threads are shown in hell. 1 and in the table.

Dimensions in mm

Note . T value R refers to the distance between threads. The actual deviation can be minus or plus sign.

3. Limit deviations of the cut of peaks and troughs (size) of an internal cylindrical thread (Fig. 2) should not exceed:

Top cut +0.05 mm (ES = +0.05 mm, EI = 0);

cut depressions ± 0.025mm (ES = +0.025mm, EI = -0.025mm)

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of Machine Tool and Tool Industry

2. APPROVED AND INTRODUCED BY Decree of the USSR State Committee for Standards No. 5789 dated December 30, 1981.

3. INSTEAD OF GOST 6211-69

4. The standard fully complies with ST SEV 1159-78

5. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

6. RE-ISSUE