GOST 9909-70
in terms of calibers
RCP 39 3177 ______________________________________________________________
Decree of the USSR State Committee for Standards dated 18 november 1981 No. 4990 the deadline for introduction is set
from 01.01.1983
Non-compliance with the standard is punishable by law
This standard applies to threaded and plain gauges for tapered threads of valves and cylinders for gases according to ST SEV 2056-79 and establishes the types of gauges, profile, length of the working part, tolerances and formulas for calculating the dimensions of threaded and smooth gauges.
The standard fully complies with ST SEV 2649-80.
1. TYPES OF GAUGE
1.1. Calibers must be manufactured types:
Gauges for external threads
1- gauge-ring threaded conical (Fig. 3);
2 - gauge-plug threaded conical control for threaded conical gauge-ring (Fig. 5);
3 - caliber-ring smooth conical (Fig. 4);
4 - smooth conical control plug gauge for a smooth conical ring gauge (Fig. 6)
Gauges for internal threads
5 - gauge-plug threaded conical (Fig. 5);
6 - smooth conical plug gauge (Fig. 6).

table 1
Oh
a t
"2*
Caliber type number
Rated
Previous off

Previous off

Rated
Previous off
"i*
1; h
2 s
hll

*.
/ Yu

-
2; 4
-
-

h
5; 6
-
-

dg t ^ . "
hll

h
Notes:1. Dimensions D/ 2 ,U, h- according to ST SEV 2056-79.
2. For calibers species 2, 4, 5 and 6 size 1s is reference.
3. Size UK is the largest and must not be less k+p.
4. TOLERANCES FOR THREAD GAUGE
4.1. Tolerances and the location of the tolerance fields of the average thread diameter of gauges for testing external threads must correspond to those indicated in Fig. 7, to control the internal thread - in hell. 8.
Note. Pins at the tolerance fields on hell. 7, 8, 10 And 11 designate numbers of types of calibers.
wear limit
caliber - kol and a
And
5
" And
E2

Crap. 7
"
1
to
I

I
,
1V
^1
1

th
i
^
MF1

5
Gauge wear limit
Crap. 8

Page 8 GOST 24998-81
4.2. Limit deviations of the angle of inclination of the side
T T
thread profile calibers ± - | p- (Fig. 1 and 2). Meaning - R is 11".
4.3. The gauge thread pitch tolerance (Ti) is 5 µm.
Notes:
1. Meaning T R refers to the distance between any threads of a gauge.
2. The actual deviation can be minus or plus sign.
4.4. Taper deviation, including the deviation of the angle of the cone and the deviation from the straightness of the generatrix (lines of average diameter), must be within the tolerance range of the average thread diameter of the gauge.
The tolerance field for the average thread diameter of the caliber is indicated in Fig. 9.
Main

Damn 9
4.5. Deviations from the coincidence of plane A of the gauge-ring of type 1 with the measuring plane of the control gauge-plug of type 2 are ±0.058 mm for the new gauge; for worn caliber +0.208 mm.
5. TOLERANCES FOR PLAIN GAUGE
5.1. The location of the tolerance fields of smooth gauges for controlling the outer diameter of the external thread must correspond to that indicated in Fig. 10, the internal diameter of the internal thread - indicated in Fig. 11.
5.2. Tolerances and values ​​that determine the position of the tolerance fields and the wear limit of the calibers must correspond to those indicated in Table. 2.
5.3. Taper deviation, including the deviation of the angle of the cone and the deviation from the straightness of the generatrix, must be within the tolerance range of the ring gauge or plug gauge.

GOST 24998-81 Page 9
5
limit is nooah "caliber-rings

Crap. 10
AND
in Sh $
O.
T
wear limit sagauge-editing
Crap. eleven
table 2
Dimensions in µm
n,
nr
100
w
200
Deviations from plane coincidence A caliber type 3 with measuring plane caliber ide 4
Hi
For a new caliber
For worn caliber
10
10
4
22
20
±0.029
+0, 154
20
10
±0.042
+0, 125
Note. Gauges with tolerances of H 2 =10 µm and H p -4 µm are manufactured at the request of the customer.
6. CALCULATION OF THREADS
6.1. The dimensions of the outer, middle and inner diameter of the thread of the gauges should be calculated according to the formulas indicated in Table. 3.

Page 10 GOST 24998-81
Table 3
«
Gauge diameters in the main plane
X
Outer
Average
Interior
Numbercaliber
Rated
Previous off
X X
Previous off

wear limit

Rated

Pre-off*
1
d+2ei along the groove, not less than
-
d* d*
~ 2

d!+2es + +0, 268+
± T *
2
d-2es-0, 268- Tpl
± T I/.
_+. T SR 2
-

d t along the groove, no more

-
5
ST D-2ES-0, 268-. PL 2
+ ZT RL
D2
T h-""-
2

D t -2EI along the groove, no more

-
- 2
Notes:
1. Values ​​es, ei, ES And EI-By ST SEV 2056-79.
2. Formulas must accept absolute values es, ei, ES and EL
Size 3 And limit deviations of the average diameter of the ring gauge type 1 are indicated to coordinate the tolerance fields of the control caliber type 2 and control of the gauge-ring with measuring instruments.
7. CALCULATION OF SMOOTH GAUGE
7.1. The dimensions of the diameters of smooth calibers should be calculated according to the formulas indicated in Table. 4.
Table 4
caliber
Caliber diameter
Number kind
Rated
Previous off
wear limit
3
d
on
*+*200
- 2
4
d
+ Nya
~ 2
6
Dx
iHl
Di Viao
±2
Note.Size and limit deviations of the caliber-ring of the form 3 indicated for tolerance field coordination control gauge type 4 and control of the gauge-ring with measuring instruments.

GOST 24998-81 Page P
APPLICATION 1 Mandatory
RULES FOR THE APPLICATION OF GAUGE
1. Threaded taper gauges of types 1 and 5 to control the axial displacement of the main plane of the thread.
When screwing a threaded conical gauge of version 1 with a controlled* conical thread, its measuring plane must coincide with the end face of the product. Permissible deviations should not exceed ±1.5 mm.
When screwing a threaded cone gauge version 2 with a controlled tapered thread, the end of the product must be between the measuring planes of the gauge or coincide with one of them.
2. Types 3 and 6 smooth taper gauges to control thread shear deviations.
Smooth taper gauges are only used in combination with threaded taper gauges. In this case, the deviation of the same-name measuring planes of smooth and threaded gauges with respect to the end face of the product should not exceed ±0.4 mm.
3. Control threaded conical gauge-plug of type 2 for the control of "threaded conical gauge-ring of type 1.
When screwing a plug gauge with a ring gauge, the measuring plane of the control gauge must coincide with plane A of the ring gauge. Permissible deviations - in accordance with clause 4.5 of this standard.
4. Control smooth taper gauge-plug of type 4 to control a smooth taper gauge-ring of type 3.
The control plug gauge must fit into the ring gauge. In this case, the measuring plane of the control gauge must coincide with the plane* A of the ring gauge. Permissible deviations - in accordance with clause 5.2 of this standard.
APPENDIX 2 Mandatory
PERFORMANCE DIMENSIONS OF CALIBERS
1. Dimensions and limit deviations of threaded gauges must correspond to those indicated in Table. 1, smooth calibers - in table. 2.

Dimensions in mm
Thread designationj
Gauge thread diameters in the main plane
ha
Outer
Average
Interior
Room view libra
X X
S OX
C O
X X
S o X
23
C o
x5
S about X
C o
W19.2
19, 250 at least
-
18, 036
Yu
oh oh
+1
18, 069
17, 220
Oh so oh oh"
+1
1
1
W27.8
27, 850 no less
26, 636
26, 669
25, 820
1
W30.3
3Q.350 not less
29, 136
29, 169
28, 320
1
W19.2
18, 864
co
oh oh"
+1
18, 036
O
oh oh"
+1
! 18, 872 no more
2
W27.8
27, 464
26, 636
25, 472 no more
W30.3
29, 964
29, 136
27, 972 no more
W19.2
18, 855
oh oh"
+1
18, 036
ST)
ooo"
+1
18, 009
16, 822 no more
-
-
5
W27.8
27, 455
26, 636
26, 609
25, 422 no more
W30.3
29, 955
29, 136
29, 109
27, 922 no more

Dimensions in them
Thread designation
Diameters caliber in the main plane
at
H smer bi da caliber ra
Rated
Previous off*
wear limit
Nomin
Previous off

Nomin
W19.2
19, 200
±0.010
19, 220
1, 375
-0, 060

-
3
W27.8
27, 800
! 27, 820
W30.3
30, 300
30, 320
W19.2
19, 200
±0.005
-
-
-

-
4
W27.8
27, 800
W30.3
30, 300
W19.2
16, 872 25, 472
±0.005
16, 850
-
-

1, 425
6
W27.8
25, 450
W3O.0
27, 972
27, 950
* At the request of the customer, gauges must be manufactured with limit 3 and ± 0.002 microns for type 4.

Page 14 GOST 24998-81
APPENDIX 3 Recommended

BASIC DIMENSIONS AND TOLERANCES OF THREADED CONE GAUGE

FOR EXTERNAL THREAD INSPECTION IN AREA /,-/ 2

AND INTERNAL THREADS ON THE PLOT 1 3 -1 2
1. Gauges for external thread control on the site 1\ -/ 2 and internal thread in section /z-/ 2 should be made of the following types:
7 - gauge-ring threaded conical for the thread section k-/ 2 (dev. 1);
8 - gauge-plug threaded conical control for threaded conical gauge-ring type 7 (Fig. 2);
9 - threaded taper gauge for the thread section U-h(Fig. 3).
2. The main dimensions and maximum deviations of calibers must correspond to those indicated in Fig. 1-3 and in table. 1.
3. When screwing a plug gauge of type 8 with a ring gauge of type 7, their measuring planes must coincide. Permissible deviations - in accordance with clause 4.5 of this standard.
4. When screwing threaded cone gauges of types 7 and 9, version 1 with a controlled thread, their measuring plane must coincide with the end face of the product. The allowable deviation should not exceed ±1.5 mm.
5. When screwing threaded cone gauges of types 7 and 9, version 2 with a controlled thread, the end of the product must be between the measuring planes or coincide with one of them.

GOST 24998-81 Page 15
Gauge-ring threaded conical for the thread section 1\-1 2
View 7
Version 1 Version 2
MainMain
hit

Shit pea you main plane

Crap. 1

Page 16 ""OCT 24998-81
Gauge-plug threaded conical control "for threaded conical gauge-ring type 7<
View 8
Execution I
Thread profile
Osnobnan
Measuring Main u^lli^_, 77 o W >+ T /o,

Crap. 2

GOST 24998-81 Page 17
Gauge plug threaded conical for the thread section h-U
View 9
Version 1
Execution 2
Measuring Main Measuring Main ovnaya

plane y planeo J; 25
Lro tp or thread P * 1, 81C

27°30"±T a1/2
b^0, b5mm s
Line parallel 0
I
1
I
II
1
thread axis thread axis
&
Crap. 3

Dimensions in mm
«
Thread designation
Gauge Thread Diameters
«
Outer
Average
Interior
Vi number. libra
Rated
Previous off
Rated
Previous off
Rated
Previous off
X
I X
W19.2
19, 250 at least
-
18, 036
±0.015
17, 220
±0.030
1, 375
-
7
W27.8
27, 850 no less
-
26, 636
±0.015
25, 820
±0.030
1, 375
-
W30.3
30, 350
at least
-
29, 136
±0.015
28, 320
±0.030
1, 375
-
W19.2
18, 864
±0.018
18, 036
±0.008
16, 872 no more
8
W27.8
27, 464
±0.018
26, 63b
±0.008
< 25, 472 не более
W30.3
29, 964
±0.018
29, 136
±0.008
27, 972 no more
-
-
W19.2
16, 339
±0.027
15, 520
±0.005
14, 306 no more
-
-
9
W27.8
24, 340
±0.027
23, 521
±0.005
22, 307 not Bolge
-
W30.3
26, 810
±0.027
26, 021
±0.005
24, 807 no more
-
-

Amendment No. 1 to GOST 24998-81 Gauges for tapered threads of valves and cylinders for gases. Tolerances
Approved and put into effect by the Decree of the USSR State Committee for Product Quality Management and Standards dated February 22, 1990 No. 257
Introduction date I 01.01.91
Introductory part, paragraphs 3.2, 6.1. Replace link: ST SEV 2056-79 on GOST 9909-81.
Clause 1.2, 2.1; drawings 3-6; table 2; annexes 1, 3. Replace the words: “measuring plane” with “control plane”.
Clause 2.1. Designation T a. Delete the word: "profile".
Clause 4.1. Note. Replace the word: "Pin" with "Numbers".
Clause 4.2. Delete the word: "profile".
Clause 4.4. The words "(lines of average diameter)" shall be supplemented with the words: "and deviation from roundness in any section".
Clause 5.3 after the words "and the deviation from the straightness of the generatrix" shall be supplemented with the words: "and the deviation from roundness in any section";
(Continued see p. 82)

(Continuation of changes to GOST 24998-81}
“Table 2. Columns “For a new caliber”, “For a worn caliber”. Foam values: ±0.029 to ±29; ±0.042 to ±42; +0.154 to +154; +0, 125 on U-125.
Annex 1. Item 2. Change the value: ±0.4 to ±0.6.
Appendix 2. Table 1. Column "Thread diameter of the gauge in the main body internal". Replace value: 18, 872 with 16, 872;
table 2. Column "Thread designation". For type caliber 6, change the dipping: W 30.0 on W 30, 3.
Annex 3. Table 1. Column l iK . Replace value: 6, 8 with 9, 8;
column "Thread diameter of the caliber". For caliber type 9, replace the values: 16.339 with 15.979; 15, 520 by 15, 160; 14, 306 by 13, 946.
(HYG #5 1990)

A

viu &p<." LX -h L
*V
**/. ^
STATESTANDARDS OF THE UNION OF THE SSR
WITH EVOLVENT PROFILECENTERED ON THE OUTER DIAMETER
CONSTRUCTION AND DIMENSIONSGOST 25157-82-GOST 25161-82

USSR STATE COMMITTEE ON STANDARDS
Moscow

DEVELOPED by the Ministry of Machine Tool and Tool Industry PERFORMERS
L. V. Baron, A. I. Liberman, A. I. Prokhorova, N. A. Kobzeva, A. S. Simkin INTRODUCED by the Ministry of Machine-Tool and Tool Industry
Deputy Minister A. E. Prokopovich
APPROVED AND INTRODUCED IN ACTION By the Decrees of the USSR State Committee for Standards of March 3, 1982 No. 936, 937

STATE STANDARDS OF THE UNION OF THE SSR

BROOCHES FOR SPLINED HOLES

WITH EVOLVENT PROFILE

WITH CENTERING

BY OUTER DIAMETER
CONSTRUCTION AND DIMENSIONSGOST 25157-82-GOST 25161-82
1 982

CONTENT
GOST 25157-82 Two-pass broaches for slotted holes with an involute profile with a diameter of 12 and 14 mm, a module of 1 mm, centered on the outer diameter. Design and dimensions... 3
GOST 25158-82 Broaches for slotted holes with an involute profile with a diameter of 15 to 90 mm, a module of 1 to 2.5 mm, centered on the outer diameter. Design and dimensions. . . . , 10
GOST 25159-82 Broaches for slotted holes with an involute profile with a diameter of 15 to 90 mm, a module of 1 to 2.5 mm with centering. two-way on the outer diameter. Design and dimensions. 126
GOST 25160-82. Broaches for slotted holes with an involute profile with a diameter of 45 to 90 mm, a module of 3 to 5 mm, centered on the outer diameter. Design and dimensions. . . .139
GOST 25161-82 Two-pass broaches for slotted holes with an involute profile with a diameter of 70 to 90 mm, a module of 3.5 to 5 mm, centered on the outer diameter. Design and dimensions. 196

(ST SEV 2056-79)

USSR STATE COMMITTEE ON STANDARDS

Moscow

STATE STANDARD OF THE UNION OF THE SSR

GOST 9909-81
Group G13

INTERSTATE STANDARD

Basic norms of interchangeability

CONICAL THREAD FOR GAS VALVES AND CYLINDERS

Basic norms of interchangeability. Taper screw thread of valves and gas cylinder

Introduction date 1983-01-01

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 dated 22.12.81 N 5566
3. INSTEAD OF GOST 9909-70 in part of sections 1 and 2
4. The standard fully complies with ST SEV 2056-79
5. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

6. RE-ISSUE

1. This standard applies to taper threads with a taper of 3:25 used for valves and gas cylinders, and establishes the profile, basic dimensions and limit deviations of dimensions, as well as its designation.

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

Taper 2 3:25; 6°524; 3°262; - outer (nominal) diameter of the outer thread (valve); - internal diameter of the external thread; - average diameter of external thread; - external (nominal) diameter of the internal thread (cylinder); - internal diameter of the internal thread; - the average diameter of the internal 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.
The bisector of the angle of the thread profile is perpendicular to the generatrix of the cone.
The thread pitch is determined along a line parallel to the generatrix of the cone.
In the main plane, the average thread diameter has a nominal value.

Table 1

In millimeters

Notes:

1. The number of steps on a length of 25.4 mm - 14.

2. The numerical value of the thread pitch is determined from the ratio with rounding to the third decimal place and is taken as the initial value when calculating the dimensions.

3. The main dimensions of the thread must correspond to those indicated in Fig. 1, 2 and in Table 2.

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

table 2
In millimeters

4. The length of the thread in the neck of the cylinder (see Fig. 2) is set constructively, making the thread through or with a length that ensures the valve is screwed in.
It is allowed to increase the length of the thread (see Table 2) taking into account the design of the valve and the requirements of GOST 949.
Note. The standard does not specify valve design beyond thread length. In particular, instead of a thread runaway, a groove can be made.

5. The symbol for the taper thread of valves and cylinders for gas must include the letter W and nominal thread diameter.
For example: W 19,2.

6. The axial displacement of the main plane of the external and internal threads (Fig. 3) from its nominal location should not exceed ± 1.5 mm.

Damn.3

In order to increase the service life of gas cylinders, it is recommended to make their threads with a negative offset of the main plane ().
Note. The axial displacement of the base plane is the sum of the deviations of the mean diameter, pitch, profile flank angle and thread taper angle.

7. Limit deviations of some thread parameters are given in the appendix.

APPENDIX (reference). LIMIT DEVIATIONS OF SOME THREAD PARAMETERS

APPLICATION
Reference

LIMIT DEVIATIONS OF SOME THREAD PARAMETERS

The limit deviations of some thread parameters given in the drawing and in the table are initial when designing a thread-forming tool and calculating thread gauges and are not controlled on the thread, unless otherwise specified.

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

In millimeters

Notes:

1. The value refers to the distance between any threads.

2. The values ​​of the difference in the average diameters over the length are not given in the standard and are calculated values.

ROSSTANDART FA for technical regulation and metrology
NEW NATIONAL STANDARDS: www.protect.gost.ru
FSUE STANDARTINFORM provision of information from the database "Products of Russia": www.gostinfo.ru
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GOST 9909-81

Group G13

INTERSTATE STANDARD

Basic norms of interchangeability

CONICAL THREAD FOR GAS VALVES AND CYLINDERS

Basic norms of interchangeability. Taper screw thread of valves and gas cylinder

Introduction date 1983-01-01

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 dated 22.12.81 N 5566

3. INSTEAD OF GOST 9909-70 in part of sections 1 and 2

4. The standard fully complies with ST SEV 2056-79

5. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

6. RE-ISSUE

1. This standard applies to taper threads with a taper of 3:25 used for valves and gas cylinders, and establishes the profile, basic dimensions and limit deviations of dimensions, as well as its designation.

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

Taper 2 3:25; 6°524; 3°262; - outer (nominal) diameter of the outer thread (valve); - internal diameter of the external thread; - average diameter of external thread; - external (nominal) diameter of the internal thread (cylinder); - internal diameter of the internal thread; - the average diameter of the internal 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.

The bisector of the angle of the thread profile is perpendicular to the generatrix of the cone.

The thread pitch is determined along a line parallel to the generatrix of the cone.

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

Table 1

In millimeters

Notes:

1. The number of steps on a length of 25.4 mm - 14.

2. The numerical value of the thread pitch is determined from the ratio with rounding to the third decimal place and is taken as the initial value when calculating the dimensions.

3. The main dimensions of the thread must correspond to those indicated in Fig. 1, 2 and in Table 2.

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

table 2

In millimeters

4. The length of the thread in the neck of the cylinder (see Fig. 2) is set constructively, making the thread through or with a length that ensures the valve is screwed in.

It is allowed to increase the length of the thread (see Table 2), taking into account the design of the valve and the requirements of GOST 949.

Note. The standard does not specify valve design beyond thread length. In particular, instead of a thread runaway, a groove can be made.

5. The symbol for the taper thread of valves and cylinders for gas must include the letter W and nominal thread diameter.

For example: W 19,2.

6. The axial displacement of the main plane of the external and internal threads (Fig. 3) from its nominal location should not exceed ± 1.5 mm.

Damn.3

In order to increase the service life of gas cylinders, it is recommended to make their threads with a negative offset of the main plane ().

Note. The axial displacement of the base plane is the sum of the deviations of the mean diameter, pitch, profile flank angle and thread taper angle.

7. Limit deviations of some thread parameters are given in the appendix.

APPENDIX (reference). LIMIT DEVIATIONS OF SOME THREAD PARAMETERS

APPLICATION
Reference

LIMIT DEVIATIONS OF SOME THREAD PARAMETERS

The limit deviations of some thread parameters given in the drawing and in the table are initial when designing a thread-forming tool and calculating thread gauges and are not controlled on the thread, unless otherwise specified.

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

In millimeters

Mechanical systems. GOST 9909-81: Basic norms of interchangeability. Tapered thread for valves and cylinders for gases. OKS: Mechanical systems and general purpose devices, Screw threads. GOSTs. Basic norms of interchangeability. Tapered thread.... class=text>

GOST 9909-81

Basic norms of interchangeability. Tapered thread for valves and cylinders for gases

GOST 9909-81
Group G13

INTERSTATE STANDARD

Basic norms of interchangeability

CONICAL THREAD FOR GAS VALVES AND CYLINDERS

Basic norms of interchangeability. Taper screw thread of valves and gas cylinder

Introduction date 1983-01-01

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 dated 22.12.81 N 5566
3. INSTEAD OF GOST 9909-70 in part of sections 1 and 2
4. The standard fully complies with ST SEV 2056-79
5. REFERENCE REGULATIONS AND TECHNICAL DOCUMENTS

6. RE-ISSUE

1. This standard applies to taper threads with a taper of 3:25 used for valves and gas cylinders, and establishes the profile, basic dimensions and limit deviations of dimensions, as well as its designation.

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

Taper 2 3:25; 6°524; 3°262; - outer (nominal) diameter of the outer thread (valve); - internal diameter of the external thread; - average diameter of external thread; - external (nominal) diameter of the internal thread (cylinder); - internal diameter of the internal thread; - the average diameter of the internal 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.
The bisector of the angle of the thread profile is perpendicular to the generatrix of the cone.
The thread pitch is determined along a line parallel to the generatrix of the cone.
In the main plane, the average thread diameter has a nominal value.

Table 1

In millimeters

Notes:

1. The number of steps on a length of 25.4 mm - 14.

2. The numerical value of the thread pitch is determined from the ratio with rounding to the third decimal place and is taken as the initial value when calculating the dimensions.

3. The main dimensions of the thread must correspond to those indicated in Fig. 1, 2 and in Table 2.

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

table 2
In millimeters

4. The length of the thread in the neck of the cylinder (see Fig. 2) is set constructively, making the thread through or with a length that ensures the valve is screwed in.
It is allowed to increase the length of the thread (see Table 2) taking into account the design of the valve and the requirements of GOST 949.
Note. The standard does not specify valve design beyond thread length. In particular, instead of a thread runaway, a groove can be made.

5. The symbol for the taper thread of valves and cylinders for gas must include the letter W and nominal thread diameter.
For example: W 19,2.

6. The axial displacement of the main plane of the external and internal threads (Fig. 3) from its nominal location should not exceed ± 1.5 mm.

Damn.3

In order to increase the service life of gas cylinders, it is recommended to make their threads with a negative offset of the main plane ().
Note. The axial displacement of the base plane is the sum of the deviations of the mean diameter, pitch, profile flank angle and thread taper angle.

7. Limit deviations of some thread parameters are given in the appendix.

APPENDIX (reference). LIMIT DEVIATIONS OF SOME THREAD PARAMETERS

APPLICATION
Reference

LIMIT DEVIATIONS OF SOME THREAD PARAMETERS

The limit deviations of some thread parameters given in the drawing and in the table are initial when designing a thread-forming tool and calculating thread gauges and are not controlled on the thread, unless otherwise specified.

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

In millimeters

Notes:

1. The value refers to the distance between any threads.

2. The values ​​of the difference in the average diameters over the length are not given in the standard and are calculated values.