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.

Taper ;j =3 ° 34 ¢ 48 ¢ ¢ ; ; d- outer diameter of the outer conical thread; d 1 - inner diameter of external conical thread; d 2 - the average diameter of the external conical thread; D- outer diameter of the internal conical thread; D 1 - internal diameter of the internal conical thread; D 2 - the average diameter of the internal conical thread; R- thread pitch; j - cone angle;j / 2 - slope angle; H- the height of the original triangle; H 1 - working height of the profile; R- the radius of rounding of the top and bottom of the thread; WITH- cut tops and bottoms of the thread. Crap. 1

Table 1

Dimensions in mm

Step R	Number of steps z at a length of 25.4 mm	H = 0,960237P	H 1 = 0,640327P	C = 0.159955 R	R = 0,137278R
0,907		0,870935	0,580777	0,145079	0,124511
1,337		1,283837	0,856117	0,213860	0,183541
1,814		1,741870	1,161553	0,290158	0,249022
2,309		2,217187	1,478515	0,369336	0,316975

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

Thread size designation	Step R	Thread diameters in the base plane			Thread length
		d = D	d 2 = D 2	d 1 = D 1	l 1	l 2
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	10,1
1 / 2	1,814	20,955	19,793	18,631	13,2
3 / 4		26,441	25,279	24,117	14,5
	2,309	33,249	31,770	30,291	16,8	10,4
1 1 / 4		41,910	40,431	38,952	19,1	12,7
1 1 / 2		47,803	46,324	44,845
		59,614	58,135	56,656	23,4	15,9
2 1 / 2		75,184	73,705	72,226	26,7	17,5
		87,884	86,405	84,926	29,8	20,6
3 1 / 2		100,330	98,851	97,372	31,4	22,2
		113,030	111,551	110,072	35,8	25,4
		138,430	136,951	135,472	40,1	28,6
		163,830	162,351	160,872

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

Thread size designation	Offset thread base plane		Limit deviations of the diameter D 2 internal parallel threads
	±D 1 l 2	±D2 l 2
1 / 16			±0.071
1 / 8
1 / 4			±0.104
3 / 8
1 / 2			±0.142
3 / 4
			±0.180
1 1 / 4
1 1 / 2
2 1 / 2			±0.217
3 1 / 2

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

Thread size designation	Limit deviations							The difference in the average thread diameters over the length l 2
	cut WITH				angle a/2	step R on length
								Rated	Limit deviations
	peaks		hollows			l 2	l 1
	es = ES	ei = EI	es = ES	ei = EI		T P			external thread	internal thread
1 / 16 ;	0,05		0,025	0,025	40 ¢	0,04	0,07	0,250	0,028	0,014
1 / 8									0,014	0,028
1 / 4					35 ¢			0,375	0,042	0,021
									0,021	0,042
3 / 8								0,400	0,044	0,022
									0,022	0,044
1 / 2								0,512	0,058	0,028
									0,028	0,058
3 / 4								0,594	0,066	0,034
									0,034	0,066
					25 ¢			0,650	0,073	0,036
									0,036	0,073
1 1 / 4 ;								0,794	0,089	0,045
1 1 / 2									0,045	0,090
								0,994	0,111	0,056
									0,056	0,111
2 1 / 2								1,094	0,122	0,062
									0,062	0,122
								1,288	0,144	0,073
									0,073	0,144
3 1 / 2								1,388	0,155	0,078
									0,078	0,155
								1,588	0,177	0,089
									0,089	0,177
								1,788	0,200	0,101
									0,101	0,200

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

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

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 USSR State Committee 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

	Item number
	Introduction, 1.2, 3.3, 4.2

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

	Number of steps per 25.4 mm length

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

Designation thread size		Thread diameters in the base plane			Thread length

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

Thread size designation	Offset thread base plane		Limit deviations of the diameter of the internal cylindrical thread
2; 3; 3; 4; 5; 6

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

Thread size designation	Previous off							Difference of average diameters threads in length
						steps in length
	peaks		hollows						Previous off
									external thread	internal thread
									0,028 -0,014	0,014 -0,028
									0,042 -0,021	0,021 -0,042
									0,044 -0,022	0,022 -0,044
									0,058 -0,028	0,028 -0,058
									0,066 -0,034	0,034 -0,066
									0,073 -0,036	0,036 -0,073
									0,089 -0,045	0,045 -0,090
									0,111 -0,056	0,056 -0,111
									0,122 -0,062	0,062 -0,122
										0,073 -0,144
									0,155 -0,078	0,078 -0,155
									0,177 -0,089	0,089 -0,177
									0,200 -0,101	0,101 -0,200

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

Thread size designation	Step P	Number of steps per length 25.4mm	H	H1	C	R	Thread diameters in the base plane			Thread length
							d=D	d2 = D2	d1 = D1	l 1	l 2
1/16"	0,907	28	0,870935	0,580777	0,145079	0,124511	7,723	7,142	6,561	6,5	4,0
1/8"							9,728	9,147	8,566
1/4"	1,337	19	1,283837	0,856117	0,213860	0,183541	13,157	12,301	11,445	9,7	6,0
3/8"							16,662	15,806	14,950	10,1	6,4
1/2"	1,814	14	1,741870	1,161553	0,290158	0,249022	20,955	19,793	18,631	13,2	8,2
3/4"							26,441	25,279	24,117	14,5	9,5
1"	2,309	11	2,217187	1,478515	0,369336	0,316975	33,249	31,770	30,291	16,8	10,4
1 1/4"							41,910	40,431	38,952	19,1	12,7
1 1/2"							47,803	46,324	44,845
2"							59,614	58,135	56,656	23,4	15,9
2 1/2"							75,184	73,705	72,226	26,7	17,5
3"							87,884	86,405	84,926	29,8	20,6
3 1/2"							100,330	98,851	97,372	31,4	22,2
4"							113,030	111,551	110,072	35,8	25,4
5"							138,430	136,951	135,472	40,1	28,6
6"							163,830	162,351	160,872

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 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)

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

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 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

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"

BSP British standard pipe thread- cylindrical pipe thread, also referred to as BSPP.

The BSP thread is interchangeable with the thread of the domestic standard GOST 6357-81.

It is used in cylindrical threaded connections, as well as in connections of an internal cylindrical thread with an external BSPT conical thread (GOST 6211-81).

Main standards:

GOST 6357-81 - Basic norms of interchangeability. The thread is pipe cylindrical.

ISO R228

EN 10226

JIS B 0202

Thread parameters: inch thread with a profile angle at the top of 55°, the theoretical profile height H=0.960491R.

Symbol according to GOST 6357-81: the letter G, the numerical value of the nominal thread diameter in inches (inch), the accuracy class of the average diameter (A, B), and the letters LH for the left thread.

For example, a thread with a nominal diameter of 1.1/8", accuracy class A - is indicated as: G 1.1/8"-A.

The pitch of cylindrical pipe thread according to GOST 6357-81 has four values ​​indicated in table 2.

The main thread dimensions GOST 6357-81 (BSP) are shown in Table 2.

Comment to table 2.
d is the outer diameter of the external thread (pipe);
D is the 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.

table 2

Cylindrical pipe thread size designation (G), pitches and nominal values ​​of the outer, middle and inner thread diameters (according to GOST 6357-81), mm

Thread size designation Thread pitch Р, mm thread pitch per inch Thread diameters First row Second row Thread BSP 1/16" Thread G1/16" Thread BSP 1/8" Thread G1/8" Thread BSP 1/4" Thread G1/4" Thread BSP 3/8" Thread G3/8" Thread BSP 1/2" Thread G1/2" Thread BSP 5/8" Thread G5/8" Thread BSP 3/4" Thread G3/4" Thread BSP 7/8" Thread G7/8" Thread BSP 1" Thread G1" Thread BSP 1.1/8" Thread G1.1/8" Thread BSP 1.1/4" Thread G1.1/4" Thread BSP 1.3/8" Thread G1.3/8" Thread BSP 1.1/2" Thread G1.1/2" Thread BSP 1.3/4" Thread G1.3/4" Thread BSP 2" Thread G2" Thread BSP 2.1/4" Thread G2.1/4" Thread BSP 2.1/2" Thread G2.1/2" Thread BSP 2.3/4" Thread G2.3/4" Thread BSP 3" Thread G3" Thread BSP 3.1/4" G-thread Thread BSP 3.1/2" Thread G3.1/2" Thread BSP 3.3/4" Thread G3.3/4" Thread BSP 4" Thread G4" Thread BSP 4.1/2" Thread G4.1/2" Thread BSP 5" Thread G5" Thread BSP 5.1/2" Thread G5.1/2" Thread BSP 6" Thread G6"

* Whitworth cut

BSPT British standard pipe tapered thread - conical pipe thread.

Based on BSW (British Standard Whitworth) threads, known as Whitworth* pipe threads.
The BSPT thread is interchangeable with the thread of the domestic standard GOST 6211-81.
It is used in conical threaded connections, as well as in connections of external conical threads with internal cylindrical threads in accordance with GOST 6357-81.
Main standards for BSPT threads:
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 1:16 taper (taper angle 3°34’48"). Profile angle at apex 55°.
Symbol according to GOST 6211-81: letter R for external thread and Rc for internal thread, numerical value of nominal thread diameter in inches (inch), letters LH for left thread. For example, a thread with a nominal diameter of 1.1/4" is designated as: R 1.1/4".

Table 1

Thread size designation, pitches and nominal values ​​of the outer, middle and inner diameters of the pipe conical thread (R), mm

Size designation carving Thread length Thread diameter in base plane From the end of the pipe to the main plane Outer d=D Average d2=D2 Interior d1=D1 Thread BSPT 1/16" Thread R1/16" Thread BSPT 1/8" Thread R1/8" Thread BSPT 1/4" Thread R1/4" Thread BSPT 3/8" Thread R3/8" Thread BSPT 1/2" Thread R1/2" Thread BSPT 3/4" Thread R3/4" Thread BSPT 1" Thread R1" Thread BSPT 1.1/4" Thread R1.1/4" Thread BSPT 1.1/2" Thread R1.1/2" Thread BSPT 2" Thread R2" Thread BSPT 2.1/2" Thread R2.1/2" Thread BSPT 3" Thread R3" Thread BSPT 3.1/2" Thread R3.1/2" Thread BSPT 4" Thread R4" Thread BSPT 5" Thread R5" Thread BSPT 6" Thread R6"

*Whitworth - (Whitworth) (Whitworth) Joseph (years of life 1803-87), English engineer and industrialist. Proposed in 1841 a screw thread profile Whitworth cut. In 1851 he created a measuring machine of great accuracy, developed a system for standardizing threads and gauges.

NPTF National Pipe Tapered Fuel is a national pipe taper fuel thread.

NPTF - sealed thread. Sealing occurs due to the collapse of the threads.
Tapered fuel pipe threads are described by ANSI/ASME B1.20.3

The NPTF fitting has a taper thread with a taper of 1:16 (taper angle φ=3°34’48").
The NPTF fitting is compatible with NPTF, NPSF or NPSM female threads.
NPTF threads are used in hydraulic systems, although the National Hydraulic Actuators Association (NFPA) does not recommend it for use in hydraulics.

On fittings with NPTF threads, to distinguish them from BSPT threads, a mark is usually placed on the faces of the hexagon

Nominal size	Outer diameter, mm	Threaded hole, mm	TPI, threads per inch	Turn pitch, mm
Thread NPTF 1/16"
Thread NPTF 1/8"
Thread NPTF 1/4"
Thread NPTF 3/8"
Thread NPTF 1/2"
Thread NPTF 3/4"
Thread NPTF 1"
Thread NPTF 1.1/4"
Thread NPTF 1.1/2"
Thread NPTF 2"
Thread NPTF 2.1/2"
Thread NPTF 4"

Tapered thread (NPT) with a taper of 1:16 (cone angle φ=3°34’48") or cylindrical (NPS) thread. Profile angle at the top 60°, theoretical profile height Н=0.866025Р.

Tapered NPT threads are described in ANSI/ASME B1.20.1.
NPT thread complies with GOST 6111-52 - Conical inch thread with a profile angle of 60 degrees.

Nominal size	Outer diameter, mm	Threaded hole, mm	TPI, threads per inch	Turn pitch, mm
Thread NPT 1/16" Thread K1/16"
Thread NPT 1/8" Thread K1/8"
Thread NPT 1/4" Thread K1/4"
Thread NPT 3/8" Thread K3/8"
Thread NPT 1/2" Thread K1/2"
Thread NPT 3/4" Thread K3/4"
Thread NPT 1" Thread K1"
Thread NPT 1.1/4" Thread K1.1/4"
Thread NPT 1.1/2" Thread K1.1/2"
Thread NPT 2" Thread K2"
Thread NPT 2.1/2" NPT
Thread NPT 3"
Thread NPT 3.1/2"
Thread NPT 4"
Thread NPT 5"
Thread NPT 6"
Thread NPT 8"
Thread NPT 10"
Thread NPT 12"

Thread Metric Metric screw threads- is widely used both in Russia and in world practice. Metric connections widely apply ISO 8434-1 DIN 2353 pipe connections.

Hydraulic connections mainly use two metric thread pitches: 1.5 pitch and 2.0 pitch.

Dimensions of commonly used hydraulic threads with a pitch of 1.5 mm: M12x1.5; M14x1.5; M16x1.5; M18x1.5; M20x1.5; M22x1.2; M24x1.5; M26x1.5; M27x1.5; M30x1.5; M33x1.5; M36x1.5; M38x1.5 M45x1.5 M52x1.5.

Dimensions of commonly used hydraulic threads with a pitch of 2.0 mm: M30x2.0; M33x2.0; M36x2.0; M42x2.0; M45x2.0; M52x2.0.

Dimensions of metric threads in fittings for high pressure hoses of domestic production (the so-called DK standard): DK (G) M16x1.5; DK(G)M18x1.5; DK(G)M20x1.5; DK(G)M22x1.5; DK(G)M27x1.5; DK(G)M33x1.5; DK(G)M33x2.0; DK(G)M36x1.5; DK(G)M36x2.0; DK(G)M42x2.0.

All profile parameters are measured in fractions of a meter (millimeters). Nominal diameter from 1 to 600 mm. Thread pitch from 0.0075 to 6 mm. The profile is an equilateral triangle (the angle at the apex is 60°) with the theoretical height of the profile Н=0.866025404Р.

Basic standards for metric threads:
GOST 9150-2002 (ISO 68-1-98): Basic standards of interchangeability. The thread is metric. Profile. Replaces GOST 9150-81 from January 1, 2004
GOST 8724-2002 Basic norms of interchangeability. The thread is metric. Diameters and steps.
GOST 9000-81 Basic norms of interchangeability. Thread metric for diameters less than 1 mm. Tolerances.
GOST 11708-82 Basic norms of interchangeability. Thread. Terms and Definitions.
GOST 16093-81 Basic norms of interchangeability. The thread is metric. Tolerances. Gap landings.
GOST 24705-81 Basic norms of interchangeability. The thread is metric. Main dimensions.
Standards: GOST 9150-81 - Basic norms of interchangeability. The thread is metric. Profile.
GOST 8724-81: Basic norms of interchangeability. The thread is metric. Diameters and steps.
ISO 965-1:1998 - ISO metric threads for general use. Tolerances. Part 1. Principles and main characteristics.
ISO 965-2:1998 - ISO metric threads for general use. Tolerances. Part 2: Thread limits for general purpose bolts and nuts. Average class of accuracy.
ISO 965-3:1998 - ISO metric threads for general use. Tolerances. Part 3: Deviations for structural threads.
ISO 965-4:1998 - ISO metric threads for general use. Tolerances. Part 4: Dimensional limits for hot dip galvanized external screw threads for assembly with tapped internal screw threads to tolerance position H or G after galvanization.
ISO 965-5:1998 - ISO metric threads for general use. Tolerances. Part 5: Dimensional limits for internal screw threads of screws for assembly with hot dip galvanized external screw threads with a maximum tolerance position dimension h before galvanization.
ISO 68-1 - ISO screw threads for general use. main profile. Metric thread.
ISO 261:1998 — ISO metric threads for general use. General form.
ISO 262:1998 - ISO metric threads for general use. Selected sizes for screws, bolts and nuts.
BS 3643 - ISO metric screw threads.
DIN 13-12-1988 - Metric ISO basic and precision threads with a diameter of 1 to 300 mm. Choice of diameters and pitches.
ANSI B1.13M, ANSI B1.18M - Metric M thread with a profile based on the ISO 68 standard.

Symbol: the letter M (metric), the numerical value of the nominal thread diameter in millimeters, the numerical value of the pitch (for threads with fine pitch) and the letters LH for left-hand threads. For example, a coarse pitch thread with a nominal diameter of 16 mm is referred to as M16; thread with a nominal diameter of 36 with a fine pitch of 1.5 mm - M36x1.5; the same in diameter and pitch but left-hand thread M36x1.5LH.
Notes:
1. The shape of the thread root of the bolt is not regulated and can be either rounded or flat-cut. A rounded cavity shape is preferred.
2. The shape of the nut thread root is not regulated.

d - outer diameter of the outer thread (bolt); D - outer diameter of the internal thread (nut); d2 - average bolt diameter; D2 - average diameter of the nut; d1 - inner diameter of the bolt; D1 - inner diameter of the nut; P - thread pitch; H is the height of the original triangle; R is the nominal radius of the bolt root; H1 - profile working height

Step R

UNF / UTS (Unified Thread Standard - inch cylindrical thread widespread in the US and Canada.
Thread profile UN/UNF: corner angle 60°, theoretical profile height H=0.866025P.

Corner angle and profile height are fully compliant with metric threads, however, all dimensions are based on the inch system of measurement and are indicated in fractions of an inch.
Depending on the step, it is divided into : UNC (Unified Coarse), UNF (Unified Fine), UNEF (Unified Extra Fine), UNS (Unified Special).
Hydraulic connections are mainly used fittings with UNF thread.

Nominal thread size UNF	Outer Diameter, Inch	Outer diameter, mm	Tap hole diameter (nut inner diameter), mm	TPI threads per inch	Turn pitch, mm
Thread UNF 0-80
Thread UNF 1-72
Thread UNF 2-64
Thread UNF 3-56
Thread UNF 4-48
Thread UNF 5-44
Thread UNF 6-40
Thread UNF 8-36
Thread UNF 10-32
Thread UNF 12-28
Thread UNF 1/4"-28
Thread UNF 5/16"-24
Thread UNF 3/8"-24
Thread UNF 7/16"-20
Thread UNF 1/2"-20
Thread UNF 9/16"-18
Thread UNF 5/8"-18
Thread UNF 3/4"-16
Thread UNF 7/8"-14
Thread UNF 1"-12
Thread UNF 1.1/8"-12
Thread UNF 1.1/4"-12
Thread UNF 1.3/8"-12
Thread UNF 1.1/2"-12