1 area of use

2 Normative references

3 Definitions

4 General provisions

5 General shape tolerances

6 General position and runout tolerances

7 Indication of general tolerances on drawings

Shape deviations limited by dimensional tolerances or orientation tolerances

Principles for assigning general tolerances to the shape and arrangement of surfaces

An example of indicating general tolerances on a drawing and their interpretation

B.1 Example of indicating general tolerances in a drawing

B.2 Interpretation of general tolerances

Interstate standard GOST 30893.2-2002 (ISO 2768-2-89)
"Basic norms of interchangeability. General tolerances. Tolerances of shape and location of surfaces not specified individually"
(put into effect by Decree of the State Standard of the Russian Federation dated June 25, 2003 N 204-st)

4 General provisions

5 General shape tolerances

6 General position and runout tolerances

7 Indication of general tolerances on drawings

APPENDIX B
(informative)

Basic norms of interchangeability. General tolerances. Tolerances of form and position for features without individual tolerance indications

1 area of use

2 Normative references

3 Definitions

4 General provisions

5 General shape tolerances

6 General position and runout tolerances

7 Indication of general tolerances on drawings

Shape deviations limited by dimensional tolerances or orientation tolerances

Principles for assigning general tolerances to the shape and arrangement of surfaces

An example of indicating general tolerances on a drawing and their interpretation

page 1

page 2

page 3

page 4

page 5

page 6

page 7

page 8

page 9

page 10

page 11

page 12

3.3 Terms and definitions of dimensional tolerances: According to GOST 25346.

4.1 General tolerances for the shape and arrangement of surfaces according to this standard apply if the drawing or other technical documentation contains a reference to this standard in accordance with section 7.

The principles for assigning general tolerances of shape and location are set out in Appendix B.

4.2 General tolerances of shape and location are established in three accuracy classes. When choosing an accuracy class, the usual accuracy of the relevant production should be taken into account. If smaller tolerances are necessary or larger tolerances are acceptable and economically advantageous, then these tolerances must be indicated directly for the corresponding elements in accordance with GOST 2.308.

4.3 The values of general tolerances of shape and location are applied regardless of the actual dimensions of the considered and basic elements (the tolerances are independent).

4.4 General tolerances for cylindricity, longitudinal section profile, inclination, axis misalignment, positional, full radial and full axial runout, the shape of a given profile and the shape of a given surface are not established. Deviations of these types are indirectly limited by tolerances for linear and angular dimensions or other types of tolerances of shape and location, including general ones. If such a limitation is not enough, then the listed types of tolerances should be indicated on the drawing directly for the corresponding elements.

5.1 Shape deviations for elements with maximum dimensional deviations indicated in the drawing in accordance with GOST 25346 must be limited within the size tolerance field (Appendix A).

5.2 General tolerances for straightness and flatness for elements with maximum deviations (general tolerances) of dimensions not indicated in the drawing are given in Table 1.

Additional requirements for limiting the general tolerance of straightness and flatness for elements with orientation tolerances indicated in the drawing (parallelism, perpendicularity, slope) are given in Appendix A.

Table 1

Dimensions in millimeters

5.3 The general roundness tolerance for elements with maximum dimensional deviations not indicated in the drawing is equal to the diameter tolerance, but should not exceed the general radial runout tolerance (6.4).

6.1 The total parallelism tolerance is equal to the dimensional tolerance between the elements under consideration. The most extended of the two elements under consideration should be taken as the base. If two elements have the same length, then either of them can be taken as the base.

6.2 General perpendicularity tolerances must correspond to those given in Table 2. The element forming the longer side of the right angle under consideration should be taken as the base. If the sides of the angle have the same nominal length, then any of them can be taken as the base.

table 2

Dimensions in millimeters

6.3 General tolerances for symmetry and intersection of axes must correspond to those given in Table 3. The element with a longer length should be taken as the base. If the elements under consideration have the same length, then any of them can be taken as the base.

Table 3

Dimensions in millimeters

6.4 General tolerances for radial and axial runout, as well as runout in a given direction (perpendicular to the generatrix) must correspond to the following:

Bearing (support) surfaces should be taken as the base if they can be unambiguously determined from the drawing, for example, specified as bases for the specified runout tolerances. In other cases, the longer of the two coaxial elements should be taken as the basis for the overall radial runout tolerance. If the elements have the same nominal length, then any of them can be taken as the base.

6.5 General alignment tolerances are applied in cases where measuring radial runout is impossible or impractical. The total alignment tolerance in diametrical terms should be taken equal to the total radial runout tolerance.

Designation of this standard;

Accuracy class of general tolerances of shape and location. For example: “General tolerances of shape and location - GOST 30893.2 -K” or “GOST 30893.2 -K”.

7.2 A reference to general tolerances of size, shape and location must include the general number of both standards for general tolerances, a designation of general size tolerances according to GOST....1 and a designation of general tolerances of shape and location according to this standard.

A.2 Shape deviations limited by the size tolerance field, and the largest values of these deviations possible with full use of the size tolerance, are given in Table A.1.

TableA.1

Type of shape deviation	Size tolerance limiting shape deviation	Drawing
1 Deviation from cylindricity, roundness and longitudinal section profile	Cylindrical surface diameter tolerance IT d		EF max = IT d
2 Deviation from flatness and straightness	a) Tolerance of the size (width, thickness) of the element under consideration IT h,		EF max = IT h
	b) Dimensional tolerance between the plane under consideration (straight line) and another plane IT h		EF max = IT h
Note- The following designations are used in the table: EF max- the largest value of shape deviation possible with full use of the size tolerance;IT with index- tolerance of the size indicated by the index.

A3 Limiting shape deviations by size tolerance is possible under the following size control conditions:

- for cylindrical and flat elements (items 1 and 2, item a) of Table A.1), the size of the element (d or h) must be controlled according to the maximum material limit (passage limit) by a means whose measuring surface has the shape of the paired part being connected and the length, equal to the length of the connection, according to the minimum material limit (no-go limit)- two-point means at all 1) points of the surface or line;

- for flat surfaces (clause 2, item b) of table A.1), the size h (between the surface under consideration (straight) and another surface taken as the base) must be controlled at all 1) points of the surface or line under consideration. Deviations in the shape of the surface taken as the base during inspection are not detected, because this surface is replaced by an adjacent plane. If necessary, its shape deviations are normalized separately.

1) Control is allowed at some characteristic points.

A.4 For particular types of shape deviations specified in paragraph 1 of Table A.1, such as ovality, cutting with an even number of faces, cone-shaped, barrel-shaped and saddle-shaped, the largest possible shape deviation is 0.5 IT d.

A.5 The largest shape deviations shown in Table A.1 are taken into account when analyzing their impact on the operation of the product and assessing the need to assign a separate, more stringent shape tolerance. However, they should not be used by the manufacturer as a form tolerance because in this case, there will be no reserve for other components of the size tolerance (machine adjustment shift by size, temperature changes in size, etc.).

A.6 For elements for which orientation tolerances (parallelism, perpendicularity, slope) are individually specified, the total flatness or straightness tolerance is equal to the orientation tolerance, but should not exceed the values in Table 1.

A.7 In foreign drawings and other technical documentation, the requirements for limiting shape deviations established in A.1 are assumed in the following cases:

for elements in which the size with the specified maximum deviations is supplemented with the symbol (E), for example 40 H7(E);

for all elements with specified dimensional deviations and unspecified shape tolerances, if the reference to general tolerances is supplemented with the letter E, for example:

Principles for assigning general tolerances to the shape and arrangement of surfaces

B.1 Elements of parts have dimensions and geometric characteristics (shape, location) of surfaces. The function of parts requires the establishment of maximum deviations in dimensions, tolerances of shape and arrangement of elements, exceeding which can lead to a violation of this function.

The limitation of the dimensions and geometry of the elements in the drawing must be complete and understood unambiguously: there should be no discrepancies and arbitrary interpretation of the requirements during manufacturing and control.

The use of general tolerances of size, shape, and location creates real prerequisites for solving this problem.

B.2 The values of general tolerances of shape and location are established according to accuracy classes, characterizing various levels of ordinary manufacturing accuracy, achieved without the use of additional high-precision processing. The choice of accuracy class is carried out taking into account the functional requirements for the part and production capabilities.

B.3 If, according to the functional requirements for an element, tolerances are required that are smaller than the general tolerances, then they must be indicated on the drawing directly for this element.

The same applies to cases where the general tolerance cannot stipulate all the conditions necessary to limit deviations in the shape and location of the element, for example, the location tolerance must relate to a base different from that specified in this standard, or may be dependent, etc.

Tolerances of shape and location not covered by this standard, if necessary, their limitations shall be indicated on the drawing, otherwise they may remain unrestricted.

B.4 Increasing tolerances beyond accepted general tolerance values does not usually provide economic advantages in manufacturing.

For example, if in the manufacture of an element with a diameter of 25 ± 0.1 mm and a length of 80 mm with a general size tolerance according to GOST 30893.1 according to accuracy class m and general tolerances of shape and location according to this standard according to accuracy class N (0.1 mm for straightness, roundness and radial runout) the usual production accuracy is equal to or exceeds the specified tolerances, then establishing coarser tolerances for a given production is not of interest.

In cases where a tolerance that exceeds the general tolerance still provides savings in manufacturing and can be allowed based on the function of the part, it is indicated directly on the drawing, for example, the roundness tolerance for a large and thin ring.

B.5 The use of general tolerances provides the following advantages:

Drawings are easier to read, communication with the user by drawings is facilitated;

The designer saves time by eliminating detailed tolerance calculations; it is enough just to know that the tolerance, based on the functional purpose of the part, is greater than or equal to the general tolerance;

The drawings clearly show which items can be produced within normal process capabilities, making quality management easier by reducing the level of inspection of these items;

The remaining elements that have individually specified tolerances are, for the most part, those for which their function requires relatively small tolerances, and which therefore may require special manufacturing effort; this circumstance facilitates production planning and helps the quality control service in analyzing control requirements;

Contracting is simplified for supply workers and subcontractors because normal production accuracy is known before contracts are awarded; This also eliminates disputes between supplier and consumer when delivering products, since the drawings, from a requirements point of view, are complete.

The listed advantages of using general tolerances will be fully realized if there is confidence that the general tolerances will not be exceeded during production, that is, that the usual manufacturing accuracy of this production ensures compliance with the general tolerances indicated on the drawings.

Determine by measurement what the normal manufacturing accuracy is for it;

When accepting drawings, pay attention to the fact that the general tolerances indicated in them correspond to or exceed its normal production accuracy;

Monitor sample deviations in the shape and location of general tolerance elements to ensure that normal manufacturing accuracy does not deviate from that originally specified.

B.6 The approach to assigning general tolerances assumes that in some cases the tolerance resulting from functional requirements exceeds the general tolerance. Therefore, accidentally exceeding the general tolerance for any element does not always lead to a malfunction of the part.

Deviations in the shape and location of an element beyond the general tolerance should not lead to automatic rejection of the part, unless the part’s ability to function is impaired.

An example of indicating general tolerances on a drawing and their interpretation

B.1 Example of indicating general tolerances in a drawing

Figure B.1

1)m - designation of general dimensional tolerances according to the “medium” accuracy class according to GOST 30893.1, N - designation of the accuracy class of general tolerances of shape and location according to this standard.

B.2 Interpretation of general tolerances

Figure B.2

Explanations for Figure B.1

1 Tolerances enclosed in circles or rectangular boxes (shown as dot-dash lines with two dashes) are general. These tolerances must be automatically achieved during machining in production, the usual accuracy of which is equal to or higher than that of GOST 30893.2 mN; Such tolerances, as a rule, do not require control.

2 Not all general tolerances are disclosed in the interpretation, in particular, for those types of deviations in shape and location that are limited by the specified or general tolerances for other types of deviations, for example, tolerances for radial runout also limit deviations from roundness.

Keywords: general tolerances, tolerances of shape and surface arrangement

(ISO 2768-2-89)

INTERSTATE STANDARD

Basic norms of interchangeability

GENERAL TOLERANCES

Tolerances of shape and location of surfaces not specified individually

Official publication

INTERSTATE COUNCIL FOR STANDARDIZATION, METROLOGY AND CERTIFICATION

Preface

1 DEVELOPED by the Research and Design Institute of Measuring Instruments in Mechanical Engineering (JSC NIIizmereniya)

2 INTRODUCED by Gosstandart of Russia

3 ADOPTED by the Interstate Council for Standardization, Metrology and Certification (Protocol No. 22 of November 6, 2002)

4 The standard is harmonized with the international standard ISO 2768-2-89 “General tolerances. Part 2. Geometric tolerances not specified individually" by changing individual phrases (words, indicator values) aimed at taking into account the specific needs of industry (or other sectors of the economy) and contains additional requirements reflecting the needs of the economy of the Russian Federation

5 By Decree of the State Committee of the Russian Federation for Standardization and Metrology dated June 25, 2003 No. 204-st, the interstate standard GOST 30893.2-2002 (ISO 2768-2-89) was put into effect directly as a state standard of the Russian Federation from January 1, 2004.

This standard cannot be fully or partially reproduced, replicated and distributed as an official publication on the territory of the Russian Federation without the permission of the State Standard of Russia

1 area of use............................................... .........1

3 Definitions................................................... ..............1

4 General provisions................................................... ...........1

5 General shape tolerances.................................................... .......2

6 General position and run-out tolerances....................................................2

7 Indication of general tolerances on drawings...................................................3

Appendix A Shape deviations limited by size tolerances or tolerances

orientation........................................................ ...4

Appendix B Principles for assigning general tolerances to the shape and location of surfaces. 5 Appendix B An example of indicating general tolerances on a drawing and their interpretation.......... 6

GOST 30893.2-2002 (ISO 2768-2-89)

INTERSTATE STANDARD

Basic norms of interchangeability GENERAL TOLERANCES Tolerances of shape and location of surfaces not specified individually

Basic norms of interchangeability. General tolerances. Tolerances of form and position for features without individual

tolerance indications

Date of introduction 2004-01-01

1 area of use

This standard applies to metal parts made by cutting and establishes general tolerances of shape and location for those elements for which these tolerances are not individually indicated in the drawing (unspecified tolerances of shape and location).

The general tolerances of this standard may also apply to non-metallic parts and parts processed by methods other than cutting, unless they are provided for in other standards and are suitable for these parts.

Additional requirements reflecting the needs of the country's economy are shown in italics (see Appendix A).

GOST 2.308-79 Unified system of design documentation. Indication on the drawings of tolerances of the shape and location of surfaces

GOST 24642-81 Basic standards of interchangeability. Tolerances of shape and location of surfaces. Basic terms and definitions

GOST 25346-89 Basic standards of interchangeability. Unified system of landing tolerances. General provisions, series of tolerances and main deviations

GOST 30893.1-2002 Basic standards of interchangeability. General tolerances. Limit deviations of linear and angular dimensions with unspecified tolerances

3 Definitions

The following terms with corresponding definitions are used in this standard:

3.1 general tolerance of shape or location: Tolerance indicated on the drawing or in other technical documents by a general entry and applied in cases where the tolerance of shape or location is not specified individually for the corresponding element of the part.

3.2 Terms and definitions of tolerances for the shape and location of surfaces: According to GOST 24642.

3.3 Terms and definitions of dimensional tolerances: According to GOST 25346.

4 General provisions

Official publication

The principles for assigning general tolerances of shape and location are set out in Appendix B.

4.3 The values of general tolerances of shape and location are applied regardless of the actual dimensions of the considered and basic elements (the tolerances are independent).

5 General shape tolerances

5.1 Shape deviations for elements with maximum dimensional deviations indicated in the drawing in accordance with GOST 25346 must be limited within the size tolerance field (Appendix A).

5.2 General tolerances for straightness and flatness for elements with maximum deviations (general tolerances) of dimensions not indicated in the drawing are given in Table 1.

Table 1

Note - The straightness tolerance is selected based on the length of the element, and the flatness

Along the length of the longer side of the surface or its diameter, if the surface is limited by a circular contour.

6 General position and runout tolerances

Table 2

Table 3

6.4 General tolerances for radial and axial runout, as well as runout in a given direction (perpendicular to the generatrix) must correspond to the following:

Accuracy class Runout tolerance, mm:

7 Indication of general tolerances on drawings

Designation of this standard;

Accuracy class of general tolerances of shape and location. For example: “General tolerances of shape and location - GOST 30893.2-K” or “GOST 30893.2-K”.

7.2 A reference to general tolerances of size, shape and location must include the general number of both standards for general tolerances, the designation of general dimensional tolerances according to GOST. . . .1 and designation of general tolerances of shape and location according to this standard.

For example: “General tolerances GOST 30893.2-mK” or “GOST 30893.2-tK” (t - accuracy class “medium” for general tolerances of linear dimensions according to GOST 30893.1, K - accuracy class for general tolerances of shape and location according to this standard).

An example of indicating general tolerances on a drawing and their interpretation is given in Appendix B.

APPENDIX A

(required)

Shape deviations limited by dimensional tolerances or orientation tolerances

A.1 For elements with maximum dimensional deviations indicated in the drawing and unspecified shape tolerances, any shape deviations are allowed within the tolerance field of the size of the element in question.

The conditions limiting shape deviations correspond to the definition of maximum dimensions according to GOST 25346. A.2 Shape deviations limited by the size tolerance field, and the largest values of these deviations possible with full use of the size tolerance, are given in Table A.1.

Table A.1

Type of shape deviation

Size tolerance limiting shape deviation1

b) Dimensional tolerance between the plane under consideration (straight line) and another IT plane

Note - The following designations are used in the table: EE max - the largest value of shape deviation possible with full use of the size tolerance; IT with index - tolerance of the size indicated by the index.

A.3 Limiting shape deviations by size tolerance is possible under the following size control conditions:

For cylindrical and flat elements (items 1 and 2, item a) of Table A.1), the size of the element (C or h) must be controlled according to the maximum material limit (throughput limit) by a means whose measuring surface has the shape of a pair of connected parts and a length equal to the length of the connection, according to the minimum material limit (no-go limit) - by a two-point means at all points of the surface or line;

For flat surfaces (item 2, item b) of Table A.1), the size h (between the surface under consideration (straight) and another surface taken as the base) must be controlled at all points of the surface or line under consideration. Deviations in the shape of the surface taken as the base during inspection are not detected, because this surface is replaced by an adjacent plane. If necessary, its shape deviations are normalized separately.

^ Control is allowed at some characteristic points.

A.5 The largest shape deviations shown in Table A. 1 are taken into account when analyzing their impact on the operation of the product and assessing the need to assign a separate, more stringent shape tolerance. However, they should not be used by the manufacturer as a form tolerance because in this case, there will be no reserve for other components of the size tolerance (machine adjustment shift by size, temperature changes in size, etc.).

A. 7 In foreign drawings and other technical documentation, the requirements for limiting shape deviations established in A. 1 are assumed in the following cases:

for elements in which the size with the specified maximum deviations is supplemented with the symbol (E), for example 40 H7 (E);

for all elements with specified dimensional deviations and unspecified shape tolerances, if the reference to general tolerances is supplemented with the letter E, for example:

"Tolerancing ISO 8015 (Applying tolerances according to ISO 8015

General tolerances ISO 2768-tK-E"; General tolerances according to ISO 2768 tK-E)

Principles for assigning general tolerances to the shape and arrangement of surfaces

B. 1 Elements of parts have dimensions and geometric characteristics (shape, location) of surfaces. The function of parts requires the establishment of maximum deviations in dimensions, tolerances of shape and arrangement of elements, exceeding which can lead to a violation of this function.

The use of general tolerances of size, shape, and location creates real prerequisites for solving this problem.

B.3 If the functional requirements for an element require tolerances smaller than the general tolerances, then they should be indicated on the drawing directly for this element.

Tolerances of shape and location not covered by this standard, if necessary, their limitations shall be indicated on the drawing, otherwise they may remain unrestricted.

B.4 Increasing tolerances beyond accepted general tolerance values does not usually provide economic advantages in manufacturing.

For example, if in the manufacture of an element with a diameter of 25 ± 0.1 mm and a length of 80 mm with a general size tolerance according to GOST 30893.1 for accuracy class m and general tolerances of shape and location according to this standard for accuracy class N (0.1 mm for straightness, roundness and radial runout) the usual production accuracy is equal to or exceeds the specified tolerances, then establishing coarser tolerances for a given production is not of interest.

B.5 The use of general tolerances provides the following advantages:

Drawings are easier to read, communication with the user by drawings is facilitated;

The drawings clearly show which items can be produced within normal process capabilities, making quality management easier by reducing the level of inspection of these items;

Determine by measurement what the normal manufacturing accuracy is for it;

When accepting drawings, pay attention to the fact that the general tolerances indicated in them correspond to or exceed its normal production accuracy;

Monitor sample deviations in the shape and location of general tolerance elements to ensure that normal manufacturing accuracy does not deviate from that originally specified.

Deviations in the shape and location of an element beyond the general tolerance should not lead to automatic rejection of the part, unless the part’s ability to function is impaired.

APPENDIX B (for reference)

An example of indicating general tolerances on a drawing and their interpretation

B.1 Example of indicating general tolerances in a drawing

Explanations for Figure B.1

1 Tolerances enclosed in circles or rectangular boxes (shown as dot-dash lines with two dashes) are general. These tolerances must be automatically achieved during machining in production, the usual accuracy of which is equal to or higher than that of GOST 30893.2 mH; Such tolerances, as a rule, do not require control.

UDC 621.753.1/.2:006.354 MKS 17.040.10 G12 OKSTU 0074

Key words: general tolerances, tolerances of shape and location of surfaces

Editor R.G. Goverdovskaya Technical editor O.N. Vlasova Corrector E.D. Dulneva Computer layout L.A. Circular

Ed. persons No. 02354 dated July 14, 2000. Delivered for recruitment on August 18, 2003. Signed for publication on September 19, 2003. Conditional oven l. 1.40.

Academic ed. l. 1.00. Circulation 1330 copies. From 12022. Zak. 817.

IPK Standards Publishing House, 107076 Moscow, Kolodezny lane, 14. http://www.standards.ru e-mail: [email protected]

Typed in the Publishing House on a PC Branch of the IPK Standards Publishing House - type. "Moscow Printer", 105062 Moscow, Lyalin lane, 6.

Interstate standard GOST 30893.2-2002 (ISO 2768-2-89)

"BASIC STANDARDS FOR INTERCHANGEABILITY. GENERAL TOLERANCES. TOLERANCES FOR THE FORM AND LOCATION OF SURFACES NOT INDIVIDUALLY SPECIFIED"

Basic norms of interchangeability. General tolerances. Tolerances of form and position for features without individual tolerance indications

Instead of GOST 25069-81

Additional requirements reflecting the needs of the country's economy are shown in italics (see Appendix A).

GOST 2.308-79 Unified system of design documentation. Indication on the drawings of tolerances of the shape and location of surfaces

GOST 24642-81 Basic standards of interchangeability. Tolerances of shape and location of surfaces. Basic terms and definitions

GOST 25346-89 Basic standards of interchangeability. Unified system of landing tolerances. General provisions, series of tolerances and main deviations

GOST 30893.1-2002 (ISO 2768-1-89) Basic standards of interchangeability. General tolerances. Limit deviations of linear and angular dimensions with unspecified tolerances

The following terms with corresponding definitions are used in this standard:

3.2 Terms and definitions of tolerances for the shape and location of surfaces: According to GOST 24642.

3.3 Terms and definitions of dimensional tolerances: According to GOST 25346.

The principles for assigning general tolerances of shape and location are set out in Appendix B.

4.3 The values of general tolerances of shape and location are applied regardless of the actual dimensions of the considered and basic elements (the tolerances are independent).

5.1 Shape deviations for elements with maximum dimensional deviations indicated in the drawing in accordance with GOST 25346 must be limited within the size tolerance field (Appendix A).

5.2 General tolerances for straightness and flatness for elements with maximum deviations (general tolerances) of dimensions not indicated in the drawing are given in Table 1.

Table 1

Dimensions in millimeters

5.3 The general tolerance for steepness for elements with maximum dimensional deviations not indicated in the drawing is equal to the tolerance for diameter, but should not exceed the general tolerance for radial runout (6.4).

table 2

Dimensions in millimeters

Table 3

Dimensions in millimeters

6.4 General tolerances for radial and axial runout, as well as runout in a given direction (perpendicular to the generatrix) must correspond to the following:

Designation of this standard;

Accuracy class of general tolerances of shape and location. For example: “General tolerances of shape and location - GOST 30893.2-K” or “GOST 30893.2-K”.

7.2 A reference to general tolerances of size, shape and location must include the general number of both standards for general tolerances, a designation of general size tolerances according to GOST... 1 and a designation of general tolerances of shape and location according to this standard.

For example: "General tolerances GOST 30893.2-mK" or "GOST 30893.2-mK" (m - accuracy class "medium" of general tolerances of linear dimensions according to GOST 30893.1, K - accuracy class of general tolerances of shape and location according to this standard).

An example of indicating general tolerances on a drawing and their interpretation is given in Appendix B.

Appendix A
(required)

The conditions limiting shape deviations correspond to the definition of maximum dimensions according to GOST 25346.

A.2 Shape deviations limited by the size tolerance field, and the largest values of these deviations possible with full use of the size tolerance, are given in Table A.1.

Table A.1

A.3 Limiting shape deviations by size tolerance is possible under the following size control conditions:

For cylindrical and flat elements (items 1 and 2, item a) of Table A.1), the size of the element (d or h) must be controlled according to the maximum material limit (throughput limit) by a means whose measuring surface has the shape of a pair of connected parts and a length equal to the length of the connection, according to the minimum material limit (no-go limit) - by two-point means at all* points of the surface or line;

For flat surfaces (item 2, item b) of Table A.1), the size h (between the surface under consideration (straight) and another surface taken as the base) must be controlled at all* points of the surface or line under consideration. Deviations in the shape of the surface taken as the base during inspection are not detected, because this surface is replaced by an adjacent plane. If necessary, its shape deviations are normalized separately.

A.7 In foreign drawings and other technical documentation, the requirements for limiting shape deviations established in A.1 are assumed in the following cases:

for elements in which the size with the specified maximum deviations is supplemented with the symbol (E), for example 40 H7 (E);

for all elements with specified dimensional deviations and unspecified shape tolerances, if the reference to general tolerances is supplemented with the letter E, for example:

"Tolerating ISO 8015	(Applying tolerances according to ISO 8015
General tolerances ISO 2768-mK-E";	General tolerances according to ISO 2768 mK-E)

______________________________

* Control is allowed at some characteristic points.

The use of general tolerances of size, shape, and location creates real prerequisites for solving this problem.

B.3 If the functional requirements for an element require tolerances smaller than the general tolerances, then they should be indicated on the drawing directly for this element.

Tolerances of shape and location not covered by this standard, if necessary, their limitations shall be indicated on the drawing, otherwise they may remain unrestricted.

B.4 Increasing tolerances beyond accepted general tolerance values does not usually provide economic advantages in manufacturing.

For example, if in the manufacture of an element with a diameter of 25 ± 0.1 mm and a length of 80 mm with a general size tolerance according to GOST 30893.1 according to accuracy class m and general tolerances of shape and location according to this standard according to accuracy class H (0.1 mm for straightness, roundness and radial runout) the usual production accuracy is equal to or exceeds the specified tolerances, then establishing coarser tolerances for a given production is not of interest.

B.5 The use of general tolerances provides the following advantages:

Drawings are easier to read, communication with the user by drawings is facilitated;

The drawings clearly show which items can be produced within normal process capabilities, making quality management easier by reducing the level of inspection of these items;

Determine by measurement what the normal manufacturing accuracy is for it;

When accepting drawings, pay attention to the fact that the general tolerances indicated in them correspond to or exceed its normal production accuracy;

Monitor sample deviations in the shape and location of general tolerance elements to ensure that normal manufacturing accuracy does not deviate from that originally specified.

Deviations in the shape and location of an element beyond the general tolerance should not lead to automatic rejection of the part, unless the part’s ability to function is impaired.

Appendix B
(informative)

Explanations for Figure B.1

Interstate standard GOST 30893.2-2002 (ISO 2768-2-89) Basic standards of interchangeability. General tolerances. Tolerances of shape and location of surfaces not specified individually

Instead of GOST 25069-81

Additional requirements reflecting the needs of the country's economy are indicated in italics (see. Appendix A).

This standard uses references to the following standards:

GOST 2.308-79 Unified system of design documentation. Indication on the drawings of tolerances of the shape and location of surfaces

GOST 24642-81 Basic standards of interchangeability. Tolerances of shape and location of surfaces. Basic terms and definitions

GOST 25346-89 Basic norms of interchangeability. Unified system of landing tolerances. General provisions, series of tolerances and main deviations

GOST 30893.1-2002 (ISO 2768-1-89) Basic standards for interchangeability. General tolerances. Limit deviations of linear and angular dimensions with unspecified tolerances

The following terms with corresponding definitions are used in this standard:

3.2 Terms and definitions of tolerances for the shape and location of surfaces: According to GOST 24642.

3.3 Terms and definitions of dimensional tolerances: By GOST 25346.

4.1 General tolerances for the shape and arrangement of surfaces according to this standard are applied if the drawing or other technical documentation contains a reference to this standard in accordance with section 7.

The principles for assigning general tolerances of shape and location are set out in Appendix B.

4.2 General tolerances of shape and location are established in three accuracy classes. When choosing an accuracy class, the usual accuracy of the relevant production should be taken into account. If smaller tolerances are required or larger tolerances are acceptable and economically advantageous, then these tolerances must be specified directly for the relevant elements according to GOST 2.308.

4.3 The values of general tolerances of shape and location are applied regardless of the actual dimensions of the considered and basic elements (the tolerances are independent).

5.1 Shape deviations for elements with maximum dimensional deviations indicated in the drawing in accordance with GOST 25346 must be limited within the size tolerance ( Appendix A).

5.2 General tolerances for straightness and flatness for elements with maximum deviations (general tolerances) of dimensions not indicated in the drawing are given in table 1.

Table 1

Dimensions in millimeters

Accuracy class	General tolerances for straightness and flatness for nominal length intervals
Accuracy class		to 10	St. 10 to 30	St. 30 to 100	St. 100 to 300	St. 300 to 1000	St. 1000 to 3000
	0,02	0,05
	0,05

Note - The straightness tolerance is selected based on the length of the element, and the flatness tolerance is selected based on the length of the larger side of the surface or its diameter if the surface is limited by a circular contour.

6.2 General perpendicularity tolerances should be as given in table 2 . The base should be taken as the element forming the longer side of the right angle under consideration. If the sides of the angle have the same nominal length, then any of them can be taken as the base.

table 2

Dimensions in millimeters

Accuracy class	General perpendicularity tolerances for nominal length intervals of the shorter side of a corner
Accuracy class		up to 100	St. 100 to 300	St. 300 to 1000	St. 1000 to 3000

6.3 General tolerances for symmetry and intersection of axes must correspond to those given in table 3 . The element with the longer length should be taken as the base. If the elements under consideration have the same length, then any of them can be taken as the base.

Table 3

Dimensions in millimeters

Accuracy class	General symmetry and axis intersection tolerances for nominal length intervals of the shorter side of a corner
Accuracy class		up to 100	St. 100 to 300	St. 300 to 1000	St. 1000 to 3000



Note - Tolerances for symmetry and intersection of axes are indicated in diametrical terms.

6.4 General tolerances for radial and axial runout, as well as runout in a given direction (perpendicular to the generatrix) must correspond to the following:

Accuracy class	Runout tolerance, mm:

Designation of this standard;

Accuracy class of general tolerances of shape and location. For example: “General tolerances of shape and location - GOST 30893.2-K” or “GOST 30893.2-K”.

For example: "General tolerances GOST 30893.2-mK" or "GOST 30893.2-mK" (m - accuracy class "average" general tolerances of linear dimensions according to GOST 30893.1 , K - accuracy class of general tolerances of shape and location according to this standard).

An example of indicating general tolerances on a drawing and their interpretation is given in Appendix B.

Appendix A

(required)

Conditions limiting shape deviations correspond to the definition of maximum dimensions according to GOST 25346.

A.2 Shape deviations limited by the size tolerance field, and the largest values of these deviations possible with full use of the size tolerance, are given in Table A. 1.

A.3 Limiting shape deviations by size tolerance is possible under the following size control conditions:

For cylindrical and flat elements (items 1 and 2, item a) of Table A. 1) the size of the element (d or h) must be controlled according to the maximum material limit (throughput limit) by a means whose measuring surface has the shape of a pair of connected parts and a length equal to connection length, according to the minimum material limit (no-go limit) - by two-point means in all* points on a surface or line;

For flat surfaces (item 2, item b) of Table A.1), the size h (between the surface under consideration (straight) and another surface taken as the base) must be controlled in all* points of the surface or line under consideration. Deviations in the shape of the surface taken as the base during inspection are not detected, because this surface is replaced by an adjacent plane. If necessary, its shape deviations are normalized separately.

A.4 For particular types of shape deviations specified inparagraph 1 of table A.1, such as ovality, cut with an even number of facets, cone-shaped, barrel-shaped and saddle-shaped, the largest possible shape deviation is 0.5 IT_d.

A.5 Given in table A.1 the largest shape deviations are taken into account when analyzing their impact on the operation of the product and assessing the need to assign a separate, more stringent shape tolerance. However, they should not be used by the manufacturer as a form tolerance because in this case, there will be no reserve for other components of the size tolerance (machine adjustment shift by size, temperature changes in size, etc.).

A.7 On foreign drawings and other technical documentation, the requirements for limiting shape deviations established in A.1 , are assumed in the following cases:

for elements in which the size with the specified maximum deviations is supplemented with the symbol (E), for example 40 H7 (E);

for all elements with specified dimensional deviations and unspecified shape tolerances, if the reference to general tolerances is supplemented with the letter E, for example:

"Tolerating ISO 8015	(Applying tolerances according to ISO 8015
General tolerances ISO 2768-mK-E";	General tolerances according to ISO 2768 mK-E)

* Control is allowed at some characteristic points.

Appendix B

The use of general tolerances of size, shape, and location creates real prerequisites for solving this problem.

Tolerances of shape and location not covered by this standard, if necessary, their limitations shall be indicated on the drawing, otherwise they may remain unrestricted.

B.4 Increasing tolerances beyond accepted general tolerance values does not usually provide economic advantages in manufacturing.

For example, if in the manufacture of an element with a diameter of 25 +- 0.1 mm and a length of 80 mm with a general size tolerance of GOST 30893.1 according to accuracy class m and general tolerances of shape and location according to this standard according to accuracy class H (0.1 mm for straightness, roundness and radial runout), the usual production accuracy is equal to or exceeds the specified tolerances, then establishing coarser tolerances for this production is not of interest .

B.5 The use of general tolerances provides the following advantages:

Drawings are easier to read, communication with the user by drawings is facilitated;

The drawings clearly show which items can be produced within normal process capabilities, making quality management easier by reducing the level of inspection of these items;

Determine by measurement what the normal manufacturing accuracy is for it;

When accepting drawings, pay attention to the fact that the general tolerances indicated in them correspond to or exceed its normal production accuracy;

Monitor sample deviations in the shape and location of general tolerance elements to ensure that normal manufacturing accuracy does not deviate from that originally specified.

Deviations in the shape and location of an element beyond the general tolerance should not lead to automatic rejection of the part, unless the part’s ability to function is impaired.

Appendix B

(informative)

Accuracy class

General tolerances for straightness and flatness for nominal length intervals

Accuracy class

St. 10 to 30

St. 30 to 100

St. 100 to 300

St. 300 to 1000

St. 1000 to 3000

Note - The straightness tolerance is selected based on the length of the element, and the flatness tolerance is selected based on the length of the larger side of the surface or its diameter if the surface is limited by a circular contour.

B.1 Example of indicating general tolerances in a drawing

B.2 Interpretation of general tolerances

Explanations for Figure B.1

______________________________

* m - designation of general dimensional tolerances according to the "average" accuracy class GOST 30893.1 , N - designation of the accuracy class of general tolerances of shape and location according to this standard.