ISO/DIS 129-1.2

Technical drawings -- Indication of dimensions and tolerances

Dessins techniques -- Indication des cotes et tolérances

Standards Content (sample)

DRAFT INTERNATIONAL STANDARD ISO/DIS 129-1.2
ISO/TC 10 Secretariat: SIS
Voting begins on Voting terminates on
2012-10-10 2012-12-10

INTERNATIONAL ORGANIZATION FOR STANDARDIZATION • МЕЖДУНАРОДНАЯ ОРГАНИЗАЦИЯ ПО СТАНДАРТИЗАЦИИ • ORGANISATION INTERNATIONALE DE NORMALISATION

Technical drawings — Indication of dimensions and
tolerances —
Part 1:
General principles
Dessins techniques — Indication des cotes et tolérances —
Partie 1: Principes généraux
[Revision of first edition (ISO 129-1:2004)]
ICS 01.100.01

To expedite distribution, this document is circulated as received from the committee

secretariat. ISO Central Secretariat work of editing and text composition will be undertaken at

publication stage.

Pour accélérer la distribution, le présent document est distribué tel qu'il est parvenu du

secrétariat du comité. Le travail de rédaction et de composition de texte sera effectué au

Secrétariat central de l'ISO au stade de publication.

THIS DOCUMENT IS A DRAFT CIRCULATED FOR COMMENT AND APPROVAL. IT IS THEREFORE SUBJECT TO CHANGE AND MAY NOT BE

REFERRED TO AS AN INTERNATIONAL STANDARD UNTIL PUBLISHED AS SUCH.

IN ADDITION TO THEIR EVALUATION AS BEING ACCEPTABLE FOR INDUSTRIAL, TECHNOLOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT

INTERNATIONAL STANDARDS MAY ON OCCASION HAVE TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL TO BECOME STANDARDS TO

WHICH REFERENCE MAY BE MADE IN NATIONAL REGULATIONS.

RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT, WITH THEIR COMMENTS, NOTIFICATION OF ANY RELEVANT PATENT RIGHTS OF WHICH

THEY ARE AWARE AND TO PROVIDE SUPPORTING DOCUMENTATION.
© International Organization for Standardization, 2012
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ISO/DIS 129-1.2
Copyright notice

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ISO/DIS 129-1.2
Contents Page

Foreword ............................................................................................................................................................ iv

Introduction ......................................................................................................................................................... v

1 Scope ...................................................................................................................................................... 1

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ISO/DIS 129-1.2
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the

International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 129-1 was prepared by Technical Committee ISO/TC 10, Technical product documentation,

Subcommittee SC , .

This second edition cancels and replaces the first edition of which has been technically revised.

ISO 129 consists of the following parts, under the general title Technical product documentation (TPD) —

Indication of dimensions and tolerances:
 Part 1: General principles
 Part 2: Dimensioning of mechanical engineering drawings
 Part 4: Dimensioning of shipbuilding drawings
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ISO/DIS 129-1.2
Introduction

ISO 129-1 is intended for all fields of application. See other parts of ISO 129 for information pertaining to

specific application areas.

The principles of tolerancing and the interpretation of tolerance indications are given in the ISO 14405 series.

Figures in this part of ISO 129 illustrate the rules and are not intended to show complete representations. It

should be understood that the third angle projection could equally well have been used without prejudice to

the principles established
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DRAFT INTERNATIONAL STANDARD ISO/DIS 129-1.2
Technical product documentation (TPD) — Indication
of dimensions and tolerances — Part 1: General
principles
1 Scope

This part of ISO 129 establishes the general principles for indication of dimensions and

tolerances that applies to technical drawings in all disciplines and trades.

NOTE Additional information and details for construction engineering are given in ISO 6284.

2 Normative references

The following referenced documents are indispensable for the application of this document. For

dated references, only the edition cited applies. For undated references, the latest edition of the

referenced document (including any amendments) applies.

ISO 128-20:1996, Technical drawings — General principles of presentation — Part 20: Basic

conventions for lines

ISO 128-22:1999, Technical drawings — General principles of presentation — Part 22: Basic

conventions and applications for leader lines and reference lines

ISO 128-23:1999, Technical drawings — General principles of presentation — Part 23: Lines

on construction drawings

ISO 128-24:1999, Technical drawings — General principles of presentation — Part 24: Lines

on mechanical engineering drawings

ISO 128-25:1999, Technical drawings — General principles of presentation — Part 25: Lines

on shipbuilding drawings

ISO 128-30:2001, Technical drawings — General principles of presentation — Part 30: Basic

conventions for views

ISO 286-1:2010, ISO system of limits and fits — Part 1: Bases of tolerances, deviations and fits

ISO 14405-1 Geometrical Product Specifications (GPS) — Geometrical tolerancing — Linear

size
ISO 14405-2 Geometrical Product Specifications (GPS) — Geometrical tolerancing —
Dimensions other than linear sizes

ISO 80000-1:2009, SI units and recommendations for the use of their multiples and of certain

other units
ISO 3098 (all parts), Technical product documentation — Lettering
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ISO/DIS 129-1.2

ISO/IEC 81714-1, Design of graphical symbols for use in the technical documentation of

products — Part 1: Basic rules
3 Terms and definitions
3.1 Features
3.1.1
feature
point, line or surface
[ISO 14660-1:1999, definition 2.1]
NOTE The term "geometrical feature" may used if risk of misunderstanding occurs.
3.1.2
feature of size
geometrical shape defined by a linear or angular dimension which is a size
[ISO 14660-1:1999, definition 2.2]

NOTE The feature of size can be a cylinder, a sphere, two parallel opposite surfaces, a cone or a

wedge.
3.1.3
reference feature

feature which is used as the origin for the determination of another feature by means of an

angular or linear dimension
3.1.4
repeated feature

feature which has the same shape and dimensions as another feature in the same part

3.2 Elements of dimensioning
3.2.1
centre line
line indicating the geometrical centre of the represented feature(s)
3.2.2
dimension line

straight or curved line indicating the extent of a feature or between two features, or between a

feature and an extension line, or between two extension lines
3.2.3
extension line
line which is an extension of a feature outline or of the position of a feature
3.2.4
leader line

continuous narrow line which establishes the connection between the features of a graphical

representation and additional alphanumeric and/or written instructions (notes, technical

requirements, item references, etc.) in an unambiguous manner
[ISO 128-22:1999, definition 3.1]
3.2.5
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ISO/DIS 129-1.2
origin symbol
circle indicating the start of running dimensioning or coordinate dimensioning
3.2.6
reference line

continuous narrow line connecting with the leader line horizontally or vertically and on or at

which the additional instructions are indicated
[ISO 128-22:1999, definition 3.2]
3.2.7
terminator
indication signifying the extremities of a dimension or leader line
3.3 Dimensions
3.3.1
dimension
distance between two features or the size of a feature of size
NOTE A dimension can be linear or angular.
3.3.2
angular dimension
angle between two features

NOTE In mechanical engineering drawings, angular dimensions are classified as angular sizes or

angular distances, see ISO 14405-2.
3.3.3
auxiliary dimension
dimensions derived from other dimensions given for information purposes only
3.3.4
dimensional value

numerical value expressed in a specific unit and indicated on drawings with lines and relevant

symbols
NOTE 1 Unit of dimension should be linear or angular.

NOTE 2 The tolerance limits and/or permissible deviations are applied to the dimensional value.

3.3.5
linear dimension
linear size of a feature or a linear distance between two features

NOTE In mechanical engineering drawings, linear dimensions are classified as linear sizes or linear

distances, see ISO 14405-2.
3.3.6
tolerance
difference between the upper limit of size and lower limit of size
[ISO 286-1:2010, definition 3.2.8]
NOTE 1 The tolerance is an absolute quantity without sign.

NOTE 2 The tolerance is also the difference between the upper limit deviation and the lower limit

deviation.
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ISO/DIS 129-1.2
3.3.7
true radius

radius which indicates that the feature which is represented elliptically in a projected view has in

reality a cylindrical shape
NOTE See Figure 23.
3.4 Arrangement of dimensions
3.4.1
chain dimensioning
method of dimensioning where several dimensions are arranged in a row
3.4.2
coordinate dimensioning
method of dimensioning from a reference feature in a coordinate system
NOTE For rectangular or polar coordinate systems, see ISO 10209.
3.4.3
parallel dimensioning

method of dimensioning from a reference feature with parallel or concentric dimension lines

3.4.4
running dimensioning

method of dimensioning from a reference feature with only one dimension line at which each

feature is dimensioned
3.4.5
tabular dimensioning

method of dimensioning where features and/or dimensions are indicated by allocated numbers

and/or letters and recorded in tables
4 Presentation of dimensions and tolerances
4.1 Presentation rules

Only the dimensions which are necessary to unambiguously define the nominal geometry of the

product shall be specified.

NOTE The dimensions shown should be for the purposes of describing the function, production or

verification of the product.
- Each feature or relation between features shall be dimensioned only once.

- Unless otherwise specified, dimensions shall be indicated for the finished state of the

dimensioned feature. However it may be necessary to give additional dimensions at

intermediate stages of production if they are shown on the same drawing (e.g. the size

of a feature prior to carburizing and finishing).

- All dimensional information shall be complete and shown directly on a drawing unless

this information is specified in related associated documentation.

All dimensions, graphical symbols and annotations shall be indicated such that they can be

read from the bottom or right-hand side (main reading directions) of the drawing.

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ISO/DIS 129-1.2

NOTE Dimensions alone are not sufficient to define the requirements of a product. Dimension shall

be used with other specification techniques as applicable, e.g. geometrical tolerancing or surface texture

requirements.
Lettering on drawings shall be in accordance with the ISO 3098 series.

There shall be only one lettering height for dimension and tolerance indication for a specific

drawing.

A space shall separate the elements of the dimension indicator (see Figures A.3 and A.4).

The dimension value and the lower deviation should be at the same distance from the dimension line.

All dimensions shall be toleranced, either via a general tolerance or by direct indication of

tolerance or limit indications, except the following cases:
 min, see 6.3.2;
 max, see 6.3.2;
 auxiliary dimension, see 7.11;
 theoretically exact dimension (TED), see ISO 1101:2012.

When tolerance limits are indicated in a vertical orientation (e.g. limit deviations, dimension limit

values) the decimal marker of the upper and lower shall be aligned. When a tolerance limit is

not shown with a decimal marker, the remaining digits would be aligned as if the decimal

marker had been displayed; e.g.:
+0,2
2× 55 -0,15
0
2× 55 -0,15

If two deviations relating to the same dimension have to be shown, both shall be expressed to

the same number of decimal places (see Figure 1), except if one of the deviations is zero. The

same applies if the limits of size are indicated (see Figure 2).
Figure 1 Figure 2

For dimensions displayed in accordance with ISO 286:2010, it is not necessary to express the

values of the deviations unless they are needed (see Figure 3).
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ISO/DIS 129-1.2
Figure 3
4.2 Positioning of dimensions

Dimensions shall be placed on that view or section which shows the relevant feature(s) most

clearly (see Figure 4).
Figure 4

Dimensions for internal features and dimensions for external features shall wherever possible

be arranged and indicated in separate groups of dimensions to improve readability (see Figure

5).
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ISO/DIS 129-1.2
Figure 5

Where several features or objects are depicted in close proximity, their relative dimensions

shall be grouped, together, separately, for ease of reading (see Figure 6).
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ISO/DIS 129-1.2
Figure 6

Whenever possible, dimensions should not be placed within the contour of the depicted item.

4.3 Units of dimensions

The units of a dimension shall be specified with the dimension. The predominant unit of

measure on a drawing may be specified on the drawing or in an associated document and the

unit omitted from the individual dimensions. Any dimensions expressed in a different unit of

measure shall indicate that unit of measure.
Limit deviations shall be expressed in the same unit as the dimensional value.
5 Elements of dimensioning - usage
5.1 General
Various elements of dimensioning are illustrated in Figure 7.
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ISO/DIS 129-1.2
Key
1 dimension line
2 dimensional value
3 terminator (in this case, an arrowhead)
4 extension line
5 leader line
6 reference line
7 origin symbol
8 centre line
Figure 7
5.2 Dimension line

Dimension lines shall be indicated as continuous narrow lines according to ISO 128-20.

Dimension lines shall be indicated in the case of
 linear dimensions parallel to the length to be dimensioned (see Figure 8);

 angular dimensions or dimensions of an arc as a circular arc around the vertex of the angle

or the centre of the arc (see Figures 9 and 10), and

 radii dimensions generated from the geometrical centre of the circle of which the arc is part

and leading to the outline of the arc (see Figure 10).

Where space is limited, dimension lines may be extended past the extension lines and the

arrowheads placed outside of the extension lines and reversed. (see Figure 4).
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ISO/DIS 129-1.2
Figure 8 Figure 9 Figure 10

Where the feature is shown broken, the corresponding dimension line shall be shown unbroken

(see Figure 11).
Figure 11

Dimension lines of holes may be indicated oblique through the centre of the hole (see Figure

12).

Intersection of dimension lines with any other line should be avoided, but where intersection is

unavoidable they shall be shown unbroken (see Figure 12).

The centre line or outline of a feature or their extensions may be used in place of an extension

line (see Figure 12). However, a centre line or the outline of a feature shall not be used as a

dimension line.
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ISO/DIS 129-1.2
Figure 12
Dimension lines may be shown not in full, when
 dimensions of diameters are indicated (see Figure 13, diameter 100);

 only a part of a symmetrical feature is drawn in a view or section (see Figures 80 and 81);

 a feature is drawn half in a view and half in a cut (see Figure 13, diameters 80 and 90);

 the reference feature for dimensioning is not on the drawing sheet and there is no need for

its indication (see Figure 45, R78);
 simplified running dimensioning is used, (see Figure 95 b).
Figure 13
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ISO/DIS 129-1.2
5.3 Terminators and origin indication
5.3.1 Terminators
Terminators shall be shown according to one of the following representations:

a) arrowheads: When an arrowhead is shown it shall be one of the following types. Only one

type of arrowhead shall be used on a single drawing or set of drawings.
1. closed 30°, Figure 14 a);
2. open 30°, Figure 14 b);
3. Open 90°, Figure 14 c)
b) oblique stroke, Figure 14 d) and 14 e);
c) point, Figure 14 f).

The size ratios of the terminators illustrated in Figure 14 are given in Annex A.

Where space is available the arrowhead terminators shall be shown between the extension

lines (see Figure 16).
Where space is limited, the arrowhead termination may be:

(a) shown outside of the extension lines on an extended dimension line (see Figure 28) or

(b) substituted with either points or oblique strokes (see Figure 28).
b) open 30°
a) closed 30°
d) oblique stroke
c) 90°
f) point between arrows
e) oblique stroke between arrows
Figure 14
5.3.2 Origin indication
The symbol origin indication can be used for e.g.
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ISO/DIS 129-1.2
 running dimensioning;

The origin symbol shall be indicated on the dimension line at the location where a specific

dimension starts (see Figure 15).

The size ratios of the origin circle illustrated in Figure 15 are given in Annex A.

Figure 15
5.4 Extension line

Extension lines shall be drawn as continuous narrow lines according to ISO 128-20.

Extension lines shall not be drawn between views and shall not be drawn parallel to the

direction of hatching.

Extension lines shall extend approximately 8 times the line width beyond their associated

dimension line.

Extension lines should be drawn perpendicular to the corresponding physical length (see

Figures 8 and 9, 13 and 17).

For circular features the extension line shall be drawn as a continuation of the feature shape

(see Figure 44).

It is permissible to have a gap, 8 times the extension line width, between the feature and the

beginning of the extension line (see Figure 17).
Figure 16
Figure 17
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ISO/DIS 129-1.2

The extension lines may be drawn oblique to the feature but shall be parallel to each other (see

Figure 18).
Figure 18

Intersecting projected contours of outlines shall extend approximately 8 times the line width

beyond the point of intersection (see Figure 19).
Figure 19

In the case of projected contours of transitions and similar features, the extension lines apply at

the point of intersection of the projection lines (see Figure 20).
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Figure 20
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ISO/DIS 129-1.2

Extension lines may be interrupted if their continuation is unambiguous (see Figures 21 and

22). In the case of angular dimensions, the extension lines are the extensions of the angle legs

(see Figure 22)
Figure 21 Figure 22

To emphasize that features have the same dimension, the features concerned shall be shown

connected by a common extension line (see Figure 23).
Figure 23
5.5 Leader line
Leader lines are drawn according to ISO 128-22.
5.6 Dimensional values
5.6.1 Indication

Dimensional values shall be indicated on drawings in characters of sufficient size to ensure

complete legibility on the original drawing as well as on reproductions made from microfilms

(see ISO 6428). Lettering ISO 3098-BVL (Type B, Vertical, Latin) is recommended.
5.6.2 Positions of dimensional values

Dimensional values shall be placed parallel to their dimension line and near the middle of and

slightly above that line (see Figures 24 and 25 and Annex A). For special cases, see clause

5.6.3.
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ISO/DIS 129-1.2

Dimensional values shall be placed in such a way that they are not crossed or separated by

any line.
Figure 24
Figure 25

Values of linear dimensions on oblique dimension lines shall be oriented as shown in Figure 26.

As stated in 4.1, the values shall be indicated so that they can be read from the bottom or right-

hand side of the drawing.

Values of angular dimensions shall be oriented as shown in Figure 27. Angular dimensions

shall be placed on top of the dimension line and follow the same rule as linear dimensions, see

4.1 and Figure 26.
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Figure 26 Figure 27
5.6.3 Special positions of dimensional values

The position of dimensional values shall be adapted according to different situations:

a) if space is limited, dimensional values shall be placed above the extension of the

dimension line beyond one of the terminators (see Figure 28);

b) if the dimension line is too short for the dimensional value to be indicated in the usual way

between the extension lines the dimensional values shall be placed on a reference line,

and attached to the dimension line by a leader line, terminating on the dimension line (see

Figure 28)

c) if space does not allow placement parallel to the dimension line, the dimensional values can

be placed above a horizontal extension of a dimension line (see Figure 29);

d) in running dimensioning, the values shall be indicated near the arrowhead (see Figures 95

a to 97).
Figure 28
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ISO/DIS 129-1.2
Figure 29
5.7 Letters representing dimensions

Letters may be used to represent dimensional values and these shall be defined on the same

drawing or in associated documentation (see Figure 30).

Letters shall be shown either as uppercase or lowercase Latin letters according to ISO 3098-2,

except for letters C, I, O, Q, q, X, Z, or letters used for dimensional symbols according to clause

7.1, i.e. R, and t.

Greek letters according to ISO 3098-3 may be shown for the indication of angular dimensions.

5.8 Symbols to dimensional values

Symbols to dimensional values, e.g. Ø for diameter, ∩ for arc length, ( ) for auxiliary

dimensions, M for metric threads, are assigned to the dimensional value and not to the letter

representing the dimension.
5.9 Tabular dimensioning

This method of dimensioning enables a series of variable common features of a feature or

assembly to be presented in tabular form (see Figure 30).
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ISO/DIS 129-1.2
Figure 30
6 Indication of tolerances
6.1 General

The normative rules for dimensional tolerancing for mechanical engineering are given in ISO

14405. However, it shall be noted that the rules from ISO 14405 may also be applied to fields

other than mechanical engineering. Some of these rules are summarized here for information.

Depending on the field of application, the tolerances of dimensions may be indicated by

 general tolerances (see 6.2),
 limit deviation (see 6.3),
 limits of dimension (see 6.4).

All tolerances apply to the represented state of the feature in the technical drawing.

6.2 General tolerances

When general tolerances are controlled by another document or method, the reference shall be

indicated on the drawing.
6.3 Limit deviations

The components of a toleranced dimension shall be indicated in the following order (see

Figures 31 to 33):
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ISO/DIS 129-1.2
a) the dimensional value;
b) the limit deviations.

A space shall separate the dimensional values and the tolerance indication, e.g.:

 55 ±0,2
 30 min
 ø10 h7

Limit deviations shall be indicated by indicating the upper deviation above the lower deviation

(see Figures 31 and 32).

If one of the two limit deviations is zero, this shall be expressed explicitly by the digit zero

shown without sign (see Figure 32).

If the tolerance is symmetrical in relation to the dimensional value, the limit deviation shall be

indicated only once, preceded by the plus-minus sign (±) (see Figure 33).
Figure 31 Figure 32 Figure 33
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6.4 Limit dimensioning
6.4.1 Upper and lower limits of dimension

The limits of dimensions shall be indicated by a maximum and a minimum (see Figure 34). The

larger dimension shall be placed above the smaller dimension.
Figure 34
6.4.2 Single limit dimensions

To limit the dimension in one direction only, the word “min” or “max” shall be added after the

dimensional value (see Figure 35).
Figure 35
7 Indications of special dimensions
7.1 Arrangement of graphical and letter symbols with dimensional values

The following symbols shall be used with dimensions to identify the feature characteristics. The

following symbols shall directly precede the dimensional value without space (see Figure 10,

Figures 36 to 43 and Table A.1):
 ø Diameter
 R Radius
  Square
 Sø Spherical diameter
 SR Spherical radius
 ⌒ Arc length
 t= Thickness of thin objects
 Depth
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 Cylindrical counterbore
 Countersink
 TRUE R Radius indication when the projected view has not a cylindrical shape
Figure 36
Figure 37
Figure 38 Figure 39
Figure 40
Figure 41

When counterbore is indicated, the diameter, and depth if needed, of the counterbore are

specified below the dimension value of the hole, see Figure 42. When countersink is indicated,

the size and angle of the countersink are specified below the dimensional value of the hole.,

see Figure 43.
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Figure 42 Figure 43
7.2 Diameters

The graphical symbol ø indicates that the cross section of the feature is a circle. The graphical

symbol ø shall precede the dimensional value (see Figures 36 and 44).

The graphical symbol ø shall be indicated when dimensioning the diameter of a circular feature.

Diameters shall be indicated when the arc to be dimensioned is ≥ 180° (see Figure 44).

When a diameter is illustrated by one arrowhead, the dimension line shall exceed the centre

(see Figure 44).
If leader lines are used for dimensioning of diameters, see 5.5.
Figure 44
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ISO/DIS 129-1.2
7.3 Radii
7.3.1 Gener
...