GOST 6111-52 Conical inch thread with a profile angle of 60°

Holes

GOST provides holes for threads with coarse pitch <1 =

1.0 - 2.2 mm.

26. Dimensions and maximum deviations of the diameters of holes in threads with fine pitch.

Dimensions, mm

Nominal thread diameter d	Thread pitch P	Threaded hole diameter with tolerance range
		4Н5Н; 5H; 5Н6Н; 6H; 7N	6G; 7G	4Н5Н; 5H	5Н6Н; 6H; 6G	7H; 7G
		Denomination		Deviations
2,5 3 3,5	0,35	2,15 2,65 3,15	2,17 2,67 3,17	+0,05	+0,07	—
4 4,5 5 5,5	0,5	3,50 4,00 4,50 5,00	3,52 4,02 4,52 5,02	+0,08	+0,10	+0,14
6	0,5 0,75	5,50 5,20	5,52 5,23	+0,08 +0,11	+0,10 +0,17	+0,14 +0,22
8	0,5 0,75 1	7,50 7,20 6,95	7,52 7,23 7,00	+0,08 +0,11 +0,17	+0,10 +0,17 +0,20	+0,14 +0,22 +0,26
10	0,5 0,75 1 1,25	9,50 9,20 8,95 8,70	9,53 9,23 9,00 8,75	+0,08 +0,11 +0,17 +0,17	+0,10 +0,17 +0,20 +0,20	+0,14 +0,22 +0,26 +0,26
12	0,5 0,75 1 1,25 1,5	11,50 11,20 10,99 10,70 10,43	11,52 11,23 11,00 10,75 10,50	+0,08 +0,11 +0,17 +0,17 +0,19	+0,10 +0,17 +0,17 +0,20 +0,22	+0,14 +0,22 +0,26 +0,26 +0,30
14	0,5 0,75 1 1,25 1,5	13,50 13,20 12,95 12,70 12,43	13,52 13,23 13,00 12,75 12,50	+0,08 +0,11 +0,17 +0,17 +0,19	+0,10 +0,17 +0,20 +0,20 +0,22	+0,14 +0,22 +0,26 +0,26 +0,30
16	0,5 0,75 1 1,5	15,50 15,20 14,95 14,43	15,52 15,23 15,00 14,50	+0,08 +0,11 +0,17 +0,19	+0,10 +0,17 +0,20 +0,22	+0,14 +0,22 +0,26 +0,30
18	0,5 0,75 1 1,5 2	17,50 17,20 16,95 16,43 15,90	17,52 17,23 17,00 16,50 15,95	+0,08 +0,11 +0,17 +0,19 +0,24	+0,10 +0,17 +0,20 +0,22 +0,30	+0,14 +0,22 +0,26 +0,30 +0,40
20	0,5 0,75 1 1,5 2	19,50 19,20 18,95 18,43 17,90	19,52 19,23 19,00 18,50 17,95	+0,08 +0,11 +0,17 +0,19 +0,24	+0,10 +0,17 +0,20 +0,22 +0,30	+0,14 +0,22 +0,26 +0,30 +0,40
22	0,5 0,75 1 1,5 2	21,50 21,20 20,95 20,43 19,90	21,52 21,23 21,00 20,50 19,95	+0,08 +0,11 +0,17 +0,19 +0,24	+0,10 +0,17 +0,20 +0,22 +0,30	+0,14 +0,22 +0,26 +0,30 +0,40
24	0,75 1 1,5 2	23,20 22,95 22,43 21,90	23,23 23,00 22,50 21,95	+0,11 +0,17 +0,19 +0,24	+0,17 +0,20 +0,22 +0,30	+0,22 +0,26 +0,30 +0,40
27	0,75 1 1,5 2	26,20 25,95 25.43 24,90	26,23 26,00 25,50 24,95	+0,11 +0,17 +0,19 +0,24	+0,17 +0,20 +0,22 +0,30	+0,22 +0,22 +0,30 +0,40
30	0,75 1 1,5 2 3	29,20 28,95 28,43 27,90 26,85	29,23 29,00 28,50 27,95 26,90	+0,11 +0,17 +0,19 +0,24 +0,30	+0,17 +0,20 +0,22 +0,30 +0,40	+0,22 +0,26 +0,30 +0,40 +0,53
33	0,75 1 1,5 2 3	32,20 31,95 31,43 30,90 29,85	32,23 32,00 31,50 30,95 29,90	+0,11 +0,17 +0,19 +0,24 +0,30	+0,17 +0,20 +0,22 +0,30 +0,40	+0,22 +0,26 +0,30 +0,40 +0,53
36	1 1,5 2 3	34,95 34,43 33,90 32,85	35,00 34,50 33,95 32,90	+0,17 +0,19 +0,24 +0,30	+0,20 +0,22 +0,30 +0,40	+0,26 +0,30 +0,40 +0,53
39	1 1,5 2 3	37,95 37,43 36,90 35,85	38,00 37,50 36,95 35,90	+0,17 +0,19 +0,24 +0,30	+0,20 +0,22 +0,30 +0,40	+0,26 +0,30 +0,40 +0,53
42	1 1,5 2 3 4	40,95 40,43 39,90 38,85 37,80	41,00 40,50 39,95 38,90 37,85	+0,17 +0,19 +0,24 +0,30 +0,36	+0,20 +0,22 +0,30 +0,40 +0,48	+0,26 +0,30 +0,40 +0,53 +0,62
45	1 1,5 2 3 4	43,95 43,43 42,90 41,85 40,80	44,00 43,50 42,95 41,90 40,85	+0,17 +0,19 +0,24 +0,30 +0,36	+0,20 +0,22 +0,30 +0,40 +0,48	+0,26 +0,30 +0,40 +0,53 +0,62

GOST provides holes for threads with D = 1.0 - 200 mm and for c1

3rd row. GOST provides a method for determining the diameters of holes for cutting metric threads for materials of high viscosity.

27. Diameters of holes for cutting inch conical threads with a profile angle of 60° according to GOST 6111-52

The dimensions of the holes for threading apply to metals and alloys that do not have high viscosity.

Dimensions, mm

With cone deployment

Without cone deployment

Thread size, inches	Number of steps per 1″	Thread pitch P	Internal thread diameter d1	Diameter of hole with reaming to cone				Drilling depth L	Hole diameter without taper
				dc		do
				Denomination	Deviations	Denomination	Deviations		Denomination	Deviations
1/16 1/8	27	0,941	6,389 8,766	6,00 8,30	+0,16 +0,20	6,39 8,76	+0,09	13 14	6,3 8,7	+0,14
1/4 3/8	18	1,411	11,314 14,797	10,70 14,25	+0,24	11,31 14,80	+0,13	20 21	11,2 14,7	+0,24
1/2 3/4	14	1,814	18,321 23,666	17,50 22,90	+0,28	18,32 23,66	+0,17	26,5	18,25 23,50	+0,24 +0,28
1 11/4	111/2	2,209	29,694 38,451	28,75 37,43	+0,28 +0,34	29,69 38,45		33,5 34,5	29,6 38,5	+0,28 +0,34
11/8			44,520	43,50	+0,34	44,52		34,5	44,5	+0,34

28. Diameters of holes for cutting cylindrical pipe threads (according to GOST 21348-75)

Diameters of holes for cutting cylindrical pipe threads in accordance with GOST 6357-81 in products made of steel in accordance with GOST 380-94, GOST 4543-71, GOST 1050-88 and GOST 5632-72 (except for nickel-based alloys) and copper in accordance with GOST 859-78 .

Nominal thread size, inches	Number of steps per 1″	Step	Threaded hole diameter			Nominal thread size, inches	Number of steps per 1″	Step	Diameter of threaded hole
			Denomination	Deviations for accuracy classes					Denomination	Deviations for accuracy classes
				A	IN

A

B 1/8 28 0.907 8.62 +0.10 +0.20 4/21 21/223/43 31/431/233/44 41/25 51/26 11 2.309 62.80 72.27 78.62 84 .97 91.07 97.42 103.77 110.12 122.82 135.52 148.22 160.92 +0.22 +0.43 1/4 3/8 19 1.337 11.50 15.00 +0 .12 +0.25 1/2 5/8 3/4 7/8 14 1.814 18.68 20.64 24.17 27.93 +0.14+0.28 1 11/8 11/413/811/ 213/4 2 11 2.309 30.34 35.00 39.00 41.41 44.90 50.84 56.70 +0.18+0.36

I. DIMENSIONS

1. The profile and dimensions of a conical inch thread with a profile angle of 60° must correspond to the drawings. 1 and table. 1.

Table 1

Designation, thread size	Number of threads per 1¢¢	Size in mm
		Thread pitch	Thread length		thread diameter in the main plane			Internal diameter of thread at the end of the pipe	Working coil height
				from the end of the pipe to the main plane
					outer	interior
d 2 = D 2	d = D	d 1 = D 1

Notes:

1. When screwing together without tension a pipe and a coupling with nominal thread sizes, the main plane of the pipe thread coincides with the end of the coupling.

2. Size d T

reference.

3. Instead of a 1/16 ¢¢ thread, it is allowed to use an M6´1 conical thread in accordance with GOST 19853.

4. The number of turns with a full profile in a threaded connection should not be less than two.

5. It is allowed to reduce the size l

2 (distance from the main plane to the end of the pipe), in this case the requirement of clause 4 of this standard regarding the difference in dimensions
l
1
-l
2 must be met.

The thread pitch is measured parallel to the thread axis.

The bisector of the profile angle is perpendicular to the thread axis.

Symbol for tapered thread 3 /

4 ¢¢
:

II. TOLERANCES

2. The pipe thread (external) is checked according to the average diameter with a thread ring gauge in accordance with GOST 6485. The axial displacement of the main plane of the pipe (Fig. 2) relative to the nominal location should not exceed (thread pitch).

Figure 2 - Pipe thread (external)

3. The coupling thread (internal) is checked according to the average diameter with a thread plug gauge in accordance with GOST 6485. The axial displacement of the main plane of the coupling (Fig. 3) relative to the nominal location should not exceed (thread pitch).

Fig.3 - Coupling thread (internal)

(Changed edition, Amendment No. 1, 2).

4. The difference in sizes must be no less than the difference between the nominal sizes and indicated in Table 1.

5. The deviation of the distances between the tops and bottoms of the threads of the tube and coupling from the line of the average diameter of the thread (and according to Figure 4) should not exceed those given in Table 2.

table 2

Thread size designation

Figure 4 - Deviation of the distances between the tops and bottoms of the tube and coupling threads from the line of the average diameter of the thread

Damn.4

(Changed edition, Amendment No. 2).

6. Deviations of half the profile angle, slope angle () and deviation in thread pitch (deviations of the distances between any turns) should not exceed those given in Table 3.

Table 3

Thread size designation	Prev. off
half profile angle	slope angle		by thread pitch
for external thread	for internal thread	at a length of up to 10 mm	at the length of St. 10 mm

CONICAL INCH THREAD WITH PROFILE ANGLE 60°

GOST 6111-52

USSR STATE COMMITTEE ON STANDARDS

STATE STANDARD OF THE USSR UNION

Approved by the Office for Standardization under the Council of Ministers of the USSR on January 10, 1952. The introduction date is set

from 01.10.52
Tested in 1984
Failure to comply with the standard is punishable by law

This standard applies to threaded connections of fuel, oil, water and air pipelines of machines and machine tools. Note. 1. In pipelines made of steel water and gas pipes in accordance with GOST 3262-75, connections with conical threads must be made in accordance with GOST 6211-81. 2. (Deleted, Amendment No. 2).

1. The profile and dimensions of a conical inch thread with a profile angle of 60° must correspond to the drawings. 1 and table. 1.

Table 1

Designation, thread size

Number of threads per 1¢¢

Size in mm

Thread pitch

Thread length

thread diameter in the main plane

Internal diameter of thread at the end of the pipe

Working coil height

from the end of the pipe to the main plane

outer

interior

d 2 = D 2

d = D

d 1 = D 1

Notes: 1. When screwing together without interference a pipe and a coupling with nominal thread sizes, the main plane of the pipe thread coincides with the end of the coupling. 2. Size d T
is for reference.
3. Instead of a 1/16 ¢ ¢ thread, it is allowed to use an M6 ´ 1 conical thread in accordance with GOST 19853-74. 4. The number of turns with a full profile in a threaded connection should not be less than two. 5. It is allowed to reduce the size l
2 (the distance from the main plane to the end of the pipe), while the requirement of clause 4 of this standard regarding the difference in sizes
l
1
- l
2 must be met.

The thread pitch is measured parallel to the thread axis.

The bisector of the profile angle is perpendicular to the thread axis.

Symbol for tapered thread 3/

4 ¢ ¢
:
TO

3
/
4 ¢ ¢
GOST 6111-52 (Changed edition, Amendment No. 2).
2. The pipe thread (external thread) is checked by the average diameter with a thread ring gauge in accordance with GOST 6485-69.
The axial displacement of the main plane of the pipe D l
2 (Fig. 2) relative to the nominal location should not exceed
±P
(thread pitch).

Crap.
2 (Changed edition, Amendment No. 1, 2).
3. The coupling thread (internal thread) is checked according to the average diameter using a thread plug gauge in accordance with GOST 6485-69.
The axial displacement of the main plane of the coupling D l
2 (Fig. 3) relative to the nominal location should not exceed
±P
(thread pitch).
(Changed edition, Amendment No. 1, 2).
4. The difference in sizes
l
1 -
l
2 must be no less than the difference indicated in the table.
1 nominal sizes l
1 and
l
2 .5.
The deviation of the distances between the tops and bottoms of the tube and coupling threads from the line of the average thread diameter (d h
1 and d
h
2 according to Fig. 4) should not exceed:

table 2

Thread size designation	h 1 = h 2 = 1 / 2 H 1	d h 1 = d h 2
1/16 and 1/8¢¢
1/4 and 3/8¢¢
1/2 and ¾ ¢ ¢

INTERSTATE STANDARD

Date of introduction 01.10.52

This standard applies to threaded connections of fuel, oil, water and air pipelines of machines and machine tools.

Notes.

1. In pipelines made of steel water and gas pipes in accordance with GOST 3262, connections with conical threads must be made in accordance with GOST 6211-81.

2. (Deleted, Amendment No. 2).

II. TOLERANCES

2. The pipe thread (external thread) is checked by the average diameter with a thread ring gauge in accordance with GOST 6485. Axial displacement of the main plane of the pipe D l

2 (Fig. 2) relative to the nominal location should not exceed
±P
(thread pitch).

3. The coupling thread (internal thread) is checked according to the average diameter using a thread plug gauge in accordance with GOST 6485-69. Axial displacement of the main plane of the coupling D l

2 (Fig. 3) relative to the nominal location should not exceed
±P
(thread pitch).

(Changed edition, Amendment No. 1, 2).

4. Size difference l

1 -
l
2 should be no less than the difference indicated in the table.
1 nominal sizes l
1 and
l
2.

5. Deviation of the distances between the tops and bottoms of the tube and coupling threads from the line of the average thread diameter (d h

1 and d
h
2 according to devil. 4) must not exceed:

table 2

(Changed edition, Amendment No. 2).

6. Deviations of half the profile angle, slope angle (j/2) and deviation in thread pitch (deviations in the distances between any turns) should not exceed:

Table 3

(Changed edition, Amendment No. 1, 2).

INFORMATION DATA

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

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GOST 6111-52

STATE STANDARD OF THE USSR UNION

CONICAL INCH THREAD WITH PROFILE ANGLE 60°

GOST 6111-52

USSR STATE COMMITTEE ON STANDARDS

Moscow

STATE STANDARD OF THE USSR UNION

CONICAL INCH THREAD WITH PROFILE ANGLE 60°

GOST 6111-52* Instead of OST 20010-38

Approved by the Office for Standardization under the Council of Ministers of the USSR on January 10, 1952. The introduction date is set

from 01.10.52

Tested in 1984

Failure to comply with the standard is punishable by law

This standard applies to threaded connections of fuel, oil, water and air pipelines of machines and machine tools.

Note.

1. In pipelines made of steel water and gas pipes in accordance with GOST 3262-75, connections with conical threads must be made in accordance with GOST 6211-81.

2. (Deleted, Amendment No. 2).

I. DIMENSIONS

1. The profile and dimensions of a conical inch thread with a profile angle of 60° must correspond to the drawings. 1 and table. 1.

Table 1

Designation, thread size	Number of threads per 1¢¢	Size in mm
		Thread pitch	Thread length		thread diameter in the main plane			Internal diameter of thread at the end of the pipe	Working coil height
			working	from the end of the pipe to the main plane
					average	outer	interior
inches	n	R	l 1	l 2	d 2= D 2	d = D	d 1= D 1	d T	H
1/16	27	0,941	6,5	4,064	7,142	7,895	6,389	6,135	0,753
1/8	27	0,941	7,0	4,572	9,519	10,272	8,766	8,480	0,753
¼	18	1,411	9,5	5,080	12,443	13,572	11,314	10,997	1,129
3/8	18	1,411	10,5	6,096	15,926	17,055	14,797	14,416	1,129
½	14	1,814	13,5	8,128	19,772	21,223	18,321	17,813	1,451
¾	14	1,814	14,0	8,611	25,117	26,568	23,666	23,128	1,451
1	11½	2,209	17,5	10,160	31,461	33,228	29,694	29,059	1,767
1¼	11½	2,209	18,0	10,668	40,218	41,985	38,451	37,784	1,767
1½	11½	2,209	18,5	10,668	46,287	48,054	44,520	43,853	1,767
2	11½	2,209	19,0	11,074	58,325	60,092	56,558	55,866	1,767

Notes:

1. When screwing together without tension a pipe and a coupling with nominal thread sizes, the main plane of the pipe thread coincides with the end of the coupling.

2. Size d T

reference.

3. Instead of a 1/16¢¢ thread, it is allowed to use an M6´1 conical thread in accordance with GOST 19853-74.

4. The number of turns with a full profile in a threaded connection should not be less than two.

5. It is allowed to reduce the size l

l
1
- l
must be met .

Crap. 1

The thread pitch is measured parallel to the thread axis.

The bisector of the profile angle is perpendicular to the thread axis.

Symbol for tapered thread 3/

4¢¢
:
TO

3
/
4¢¢
GOST 6111-52
(Changed edition, Amendment No. 2).

II. TOLERANCES

2. The pipe thread (external thread) is checked by the average diameter with a thread ring gauge in accordance with GOST 6485-69. Axial displacement of the main plane of the pipe D l

2 (Fig. 2) relative to the nominal location should not exceed
±P
(thread pitch).

Crap. 2

(Changed edition, Amendment No. 1, 2).

3. The coupling thread (internal thread) is checked according to the average diameter using a thread plug gauge in accordance with GOST 6485-69. Axial displacement of the main plane of the coupling D l

2 (Fig. 3) relative to the nominal location should not exceed
±P
(thread pitch).

Crap. 3

(Changed edition, Amendment No. 1, 2).

4. Size difference l

1-
l
2 should be no less than the difference indicated in the table.
1 nominal sizes l
1 and
l
2.

5. Deviation of the distances between the tops and bottoms of the tube and coupling threads from the line of the average thread diameter (d h

1 and d
h
2 according to devil. 4) must not exceed:

table 2

Thread size designation	h 1= h 2=1/2 H 1	dh 1=d h 2
	mm
1/16 and 1/8¢¢	0,3765	-0,045
1/4 and 3/8¢¢	0,5645	-0,065
1/2 and ¾¢¢	0,7255	-0,085
1 — 2¢¢	0,8835	-0,085

Crap. 4

(Changed edition, Amendment No. 2).

6. Deviations of half the profile angle, slope angle (j/2) and deviation in thread pitch (deviations in the distances between any turns) should not exceed:

Table 3

Thread size designation inches	Maximum deviation
	half profile angle	slope angle		by thread pitch
		for external thread	for internal thread	at a length of up to 10 mm	at the length of St. 10 mm
				mm
1/16 and 1/8¢¢	±1°	+12¢	-12¢	±0,02	±0,04
		-6¢	+6¢
1/4 — 2¢¢	±45¢	+10¢	-10¢
		-5¢	+5¢

(Changed edition, Amendment No. 1, 2).

I. DIMENSIONS

I. DIMENSIONS

1. The profile and dimensions of a conical inch thread with a profile angle of 60° must correspond to Figure 1 and Table 1.

Fig. 1 - Conical inch thread

; ; ; taper Fig.1

The thread pitch is measured parallel to the thread axis. The bisector of the profile angle is perpendicular to the thread axis.

Example of a symbol for a tapered thread:

K
GOST 6111-52
Table 1 Dimensions in millimeters

Designation, thread size, inches	Number of threads per	Thread pitch	Thread length		Thread diameter in the main plane			Internal diameter of thread at the end of the pipe	Working coil height
from the end of the pipe to the main plane	outer	interior

Notes:

1. When screwing together without tension a pipe and a coupling with nominal thread sizes, the main plane of the pipe thread coincides with the end of the coupling.

2. Size is for reference.

3. Instead of threads, it is allowed to use conical threads M6x1 in accordance with GOST 19853.

4. The number of turns with a full profile in a threaded connection should not be less than two.

5. It is allowed to reduce the size (distance from the main plane to the end of the pipe), while the requirement of paragraph 4 regarding dimensions must be met.

NPT/NPTF tapered thread: main characteristics and standards

Appearance of a tapered NPT thread NPT/NPTF (national pipe taper/national pipe tapered fuel) thread is an American standard for tapered pipe threads. This standard applies to pipes and fittings that are manufactured in the USA.

NPT tapered pipe thread complies with GOST 6111-52 “Inch tapered thread with a profile angle of 60 degrees”, which is valid in most CIS countries.

The United States National Hydraulic Transmission Association advises against the use of NPT and NPTF standards in hydraulics. But despite this, the use of these standards is very widespread.

NPT thread diagram

Types of inch threads:

• NPT – thread with a taper of 1:16 and a profile angle of 60°. This thread complies with ANSI B1.21.1, FED-STD-H28/7 standards.
• NPS – cylindrical thread.
• NPTF - sealed inch thread with a profile angle of 60°, sealing occurs due to thread compression. This type of inch thread complies with SAE J476, ANSI B1.20.3, FED-STD-H28/8 standards.

Main parameters of the most common NPTF threaded connections:

Nominal diameter, inch	Main diameter, mm	Threaded hole, mm	Threads per inch	Pitch, mm
NPTF 1/16″	7.870	6.00	27	0.940
NPTF 1/8″	10.217	8.25	27	0.940
NPTF 1/4″	13.577	10.70	18	1.411
NPTF 3/8″	17.016	14.10	18	1.411
NPTF 1/2″	21.211	17.40	14	1.814
NPTF 3/4″	26.566	22.60	14	1.814
NPTF 1″	33.195	28.50	11.5	2.209
NPTF 1 1/4″	41.952	37.00	11.5	2.209
NPTF 1 1/2″	48.021	43.50	11.5	2.209
NPTF 2″	60.060	55.00	11.5	2.209
NPTF 2 1/2″	72.642	65.50	8	3.175
NPTF 4″	113.913	107.00	8	3.175

Main parameters of the most common NPT threaded connections:

Nominal diameter, inch	Main diameter, mm	Threaded hole, mm	Threads per inch	Pitch, mm
NPT 1/16″	7.870	6.00	27	0.940
NPT 1/8″	10.217	8.25	27	0.940
NPT 1/4″	13.577	10.70	18	1.411
NPT 3/8″	17.016	14.10	18	1.411
NPT 1/2″	21.211	17.40	14	1.814
NPT 3/4″	26.566	22.60	14	1.814
NPT 1″	33.195	28.50	11.5	2.209
NPT 1 1/4″	41.952	37.00	11.5	2.209
NPT 1 1/2″	48.021	43.50	11.5	2.209
NPT 2″	60.060	55.00	11.5	2.209
NPT 2 1/2″	72.642	65.50	8	3.175
NPT 4″	113.913	107.00	8	3.175
NPT 5″	141,300	134,384	8	3.175
NPT 6″	168,275	161,191	8	3.175
NPT 8″	219,075	211,673	8	3.175
NPT 10″	273,050	265,311	8	3.175
NPT 12″	323,850	315,793	8	3.175

To create an NPT (NPTF) connection, special threading machines with a tap (die or threading head) are used.

BREXIT brings to your attention equipment with which you can cut NPT (NPTF) threads on pipes and workpieces with high quality:

• Die heads from 1/2 to 2 inches. Designed for high-quality, high-performance thread cutting. Safe and quick replacement.
• Manual threading dies from 1/2 to 1.1/4 inches. Designed for cutting conical pipe threads on water, electrical or gas pipes. It has high performance and is easy to transport.
• Manual threading dies from 1/2 to 2 inches. Can be widely used in equipment installation and construction industry, ideal for increasing labor productivity, reducing construction time, ensuring its quality, and reducing labor intensity.
• Electric threading machines from 1/2 to 2 inches. High-performance threading machine for mobile and stationary use. Suitable for long-term, intensive use in the workshop and on the construction site, used in the installation of heating and water supply systems and in mass production. The machine cuts precise threads of very high quality.
• Electric threading machines from 1/2 to 3 inches. The machine is designed for cutting screw and cylindrical threads on pipes. Used to produce precise, reliable threaded connections on pipes and bolts in accordance with codes. It is designed for long-term industrial use.
• Electric threading machines from 1/2 to 4 inches. The machine is designed for cutting pipe and metric threads. Used for the manufacture of precise, reliable threaded connections on pipes and studs in accordance with standards.

NPT threads are used in connections with increased tightness requirements. Connections with such threads are able to withstand strong pressure of the circulating medium through the pipeline.

To buy equipment for cutting NPT (NPTF) tapered threads on pipes, contact BREXIT managers by contact numbers: +375 (17) 256-22-55, +375 (29) 602-00-80, +375 (29) 766 -07-00, we will tell you in detail about the operating features, design and specifics of this type of equipment.

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INTERSTATE STANDARD

CONICAL INCH THREAD WITH PROFILE ANGLE 60°

GOST 6111-52*

Date of introduction 01.10.52

This standard applies to threaded connections of fuel, oil, water and air pipelines of machines and machine tools.

Note.

1. In pipelines made of steel water and gas pipes in accordance with GOST 3262-75, connections with conical threads must be made in accordance with GOST 6211-81.

2. (Deleted, Amendment No. 2).

1. The profile and dimensions of a conical inch thread with a profile angle of 60° must correspond to the drawings. 1 and table. 1.

Crap. 1

The thread pitch is measured parallel to the thread axis.

The bisector of the profile angle is perpendicular to the thread axis.

Example of symbol for tapered thread 3/

4¢¢
:
K

3
/
4¢¢
GOST 6111-52
(Changed edition, Amendment No. 2).

Table 1

Dimensions in millimeters

Designation, thread size, inches	Number of threads per 1¢¢ n	Thread pitch R	Thread length		Thread diameter in the main plane			Internal diameter of thread at the end of the pipe dT	Working coil height H
			working l 1	from the end of the pipe to the main plane l 2	average d 2= D 2	outer d = D	interior d 1= D 1
1/16	27	0,941	6,5	4,064	7,142	7,895	6,389	6,135	0,753
1/8			7,0	4,572	9,519	10,272	8,766	8,480
¼	18	1,411	9,5	5,080	12,443	13,572	11,314	10,997	1,129
3/8			10,5	6,096	15,926	17,055	14,797	14,416
½	14	1,814	13,5	8,128	19,772	21,223	18,321	17,813	1,451
¾			14,0	8,611	25,117	26,568	23,666	23,128
1	11½	2,209	17,5	10,160	31,461	33,228	29,694	29,059	1,767
1¼			18,0	10,668	40,218	41,985	38,451	37,784
1½			18,5		46,287	48,054	44,520	43,853
2			19,0	11,074	58,325	60,092	56,558	55,866

Notes:

1. When screwing together without tension a pipe and a coupling with nominal thread sizes, the main plane of the pipe thread coincides with the end of the coupling.

2. dT

reference.

3. Instead of a 1/16¢¢ thread, it is allowed to use an M6´1 conical thread in accordance with GOST 19853-74.

4. The number of turns with a full profile in a threaded connection should not be less than two.

5. It is allowed to reduce the size l

l
1
- l
must be met .

2. The pipe thread (external thread) is checked by the average diameter with a thread ring gauge in accordance with GOST 6485-69. Axial displacement of the main plane of the pipe D l

2 (Fig. 2) relative to the nominal location should not exceed
±P
(thread pitch).

Crap. 2

(Changed edition, Amendment No. 1, 2).

3. The coupling thread (internal thread) is checked according to the average diameter using a thread plug gauge in accordance with GOST 6485-69. Axial displacement of the main plane of the coupling D l

2 (Fig. 3) relative to the nominal location should not exceed
±P
(thread pitch).

Crap. 3

(Changed edition, Amendment No. 1, 2).

4. Size difference l

1-
l
2 should be no less than the difference indicated in the table.
1 nominal sizes l
1 and
l
2.

5. Deviation of the distances between the tops and bottoms of the tube and coupling threads from the line of the average thread diameter (d h

1 and d
h
2 according to devil. 4) must not exceed:

table 2

Thread size designation	h 1= h 2=1/2 H 1	dh 1=d h 2
	mm
1/16 and 1/8¢¢	0,3765	-0,045
1/4 and 3/8¢¢	0,5645	-0,065
1/2 and ¾¢¢	0,7255	-0,085
1 — 2¢¢	0,8835

Crap. 4

(Changed edition, Amendment No. 2).

6. Deviations of half the profile angle, slope angle (j/2) and deviation in thread pitch (deviations in the distances between any turns) should not exceed those given in table. 3.

Table 3

Thread size designation inches	Maximum deviation
	half profile angle	slope angle		by thread pitch
		for external thread	for internal thread	at a length of up to 10 mm	at the length of St. 10 mm
				mm
1/16¢¢ and 1/8¢¢	±1°	+12¢	-12¢	±0,02	±0,04
		-6¢	+6¢
¼¢¢ – 2¢¢	±45¢	+10¢	-10¢
		-5¢	+5¢

(Changed edition, Amendment No. 1, 2).

INFORMATION DATA

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

2. APPROVED AND ENTERED INTO EFFECT by the Office for Standardization under the Council of Ministers of the USSR on January 10, 1952.

3. INSTEAD OST 20010-38

4. REFERENCE REGULATIVE AND TECHNICAL DOCUMENTS

Designation of the referenced technical document	Item number
GOST 3262-75	Introductory part
GOST 6211-81	»
GOST 6485-69	2, 3
GOST 19853-74	1

5. The validity period was lifted according to Gosstandart Decree dated December 18, 1984 No. 4538 (IUS 3-85)

6. EDITION with Amendments No. 1, 2, approved in December 1969, December 1984 (IUS 1-70, 3-85)

Diameter of hole for GOST thread (Table)

The reference tables contain the dimensions of the diameters of holes for threading according to GOST 9150-59, GOST 6357-52, GOST 6111-52 and GOST 6211-52

1. The tables are for reference, issued on the basis of the plant’s guidelines 01.2РМ31-65 and normals МН5384-5389-64 and are intended for foremen, technologists and workers of main and auxiliary production.

2. The sizes of holes for threads with large pitches are highlighted in bold text.

3. The diameter of holes indicated without tolerances is carried out according to class 4 accuracy.

Diameters of holes for threading according to GOST 9150-59

Nominal thread diameter	Diameters of holes for threading according to GOST 9150-59
	Thread pitches S
	0,2	0,25	0,3	0,35	0,4	0,45	0,5	0,6	0,7	0,75	0,8	1	1,25	1,5
1	0,8	0,75
1,4	1,1
1,6	1,25
2,0	1,75	1,6
2,5	2,15	2,05
3	2,65	2,5
3,5	3,15	2,9
4	3,5	3,3
4,5	4	3,8
5	4,5	4,2
6	5,5	5,2	5
8	7,5	7,2	7	6,7
10	9,5	9,2	9	8,7	8,5

Nominal thread diameter	Diameter of holes for threading according to GOST 9150-59
	Thread pitches S
	0,75	1	1,25	1,5	1,75	2	2,5	3	3,5	4
12	11,2	11	10,7	10,5	10,2
14	13,2	13	12,7	12,5	11.9A5
16	15,25	15	14,5	14
18	17	16,5	16	15.35A5
20	18,95	18,45	18	17.35A5
22	20,95	20,45	20	19.35A5
24	22,45	21.85A5	20.85A5
27	25,45	25	23.85A5
30	28,45	28	26.85A5
33	29.85A5	29.35A5
36	32.8A5	31.8A5
39	34.8A5

Nominal thread diameter	Diameters of holes for threading according to GOST 9150-59
	Thread pitches S
	1	1,5	2	3	4	4,5	5	5,5	6
42	40,95	40,45	—	38,9	37.8A5	37,ZA5	—	—	—
45	43,95	43,45	42,95	41,9	40.8A5	40,ZA5	—	—	—
48	46,95	46,45	45,95	44,9	43.8A5	42.8A5	—	—
52	50,43	45,95	48,9	47.8A5	—	46.8A5	—	—
56	54,43	53,9	52,9	51,9	—	—	50,ZA5	—
60	58,4	57,9	56,9	55,9	—	—	54,ZA5	—
64	62,4	61,9	60,9	59,9	—	—	—	57.8A5
68	66,4	65,9	64,9	63,9	—	—	—	61.8A5
72	70,4	69,9	68,9	67,9	—	—	—	65.8A5	‘
76	74,4	73,9	72,9	71,9	—	—	—	69.8A5
80	78,4	77,9	76,9	75,9	—	—	—	73.8A5
85	83,4	82,9	81,9	80,9	—	—	—	78.8A5
90	88,4	87,9	86,9	85,9	—	—	—	83.75A5

For metals of high viscosity / (aluminum-magnesium alloys)
Nominal thread diameter	Diameter for holes for threading according to GOST 9150-59
	Thread pitches S
	0,25	0,3	0,35	0,4	0,45	0,5	0,6	0,7	0,8	1	1,25	1,5	1,75	2
1	0,8
1,4	1.15
1,6	1,3
2	1,65
2,5	2,15
3	2,6
3,5	3
4	3,35
5	4,25
6	5,1
8	6,8
10	8,6
12	10,8	10,6
14	12,6	12,1

Diameters of holes for cutting cylindrical pipe threads according to GOST 6357-52

Diameters of holes for cutting cylindrical pipe threads according to GOST 6357-52
Thread designation, inches	drill diameter, mm
	thread accuracy class
	2	3
1/8	8.65A4	8.7A5
1/4	11.5A4	11.5A5
3/8	15A4	15A5
1/2	18.7A,	18.7A5
5/8	20,7+0,12	20.7A5
3/4	24,2+0,15	24.2A5
7/8	28+0,12	28A5
1	30,43+0,16	30,43+0,29
1·1/8	35A4	35A5
1·1/4	39A4	39A5
1·3/8	—	41.5A5
1·1/2	—	45A5

Diameters of holes for threading according to OST NKTP 1260

Diameters of holes for cutting inch threads according to OST NKTP 1260
Thread designation, inches	Drill diameter, mm	Thread designation, inches	Drill diameter, mm
3/16	3,6	1	22
1/4	5	1·1/8	24,75
5/16	6,4	1·1/4	27,75
3/8	7,8	1·3/8	30,25
7/16	9,1	1·1/2	33,5
1/2	10,4	1·5/8	35,75
9/16	12	1·3/8	39
5/8	13,3	1·7/8	41,5
3/4	16,25	2	44,5
7/8	19,25

Hole diameter GOST 6111-52

Diameter of holes for cutting inch conical threads with reaming to a cone, GOST 6111-52
Thread diameter	Number of threads per 1″	dc	do	Drill depth. e mm
1/8	27	8,ZA5	8.76A4	15
1/4	18	10.7A5	11.31A4	20
3/8		14.25A5	14.8A4	22
1/2	14	17.5A5	18.32A4	28
3/4		22.9A5	23.66A4	28
1	11·1/2	28.75A5	29.69A4	35
1·1/4		37.43A5	38.45A4	36
1·1/2		43.5A5	44.52A4	36
2		55.5A4	56.54A4	37

Hole diameter GOST 6211-52

Diameter of holes for cutting conical pipe threads with reaming to a cone, GOST 6211-52
Thread diameter	Number of threads per 1″	dc	d°	I'll drill the depth. e mm
1/8	28	8.1A5	8.57A4	15
1/4	19	10.8A5	11.45A4	20
3/8		14.25A5	14,95+0,1	24
1/2	14	17.9A5	18,63+0,1	29
3/4		23.25A5	24,12+0,1	31
1	11	29.25A5	30.30А3а	37
1·1/4		37.75A5	38.95A3a	40
1·1/2		43.5A5	44.83A3a	42
2		55A5	56.54A3a	44

Source of information: PA “Mashzavod im. October Revolution" 1986.