measuring principles for geometrical tolerances - volvo · standard std 112-0004 volvo group issue...

Standard STD 112-0004 Volvo Group

Issue date January 2017 Issue 3 (41)

The English language version is the original and the reference in case of dispute.

Measuring principles for geometrical tolerances Indication, definitions and system structure

Orientation

This standard establishes the rules that apply in the Volvo Group when measuring principles are specified

together with geometrical tolerances.

There is no international equivalent to this standard, although there are similarities with the technical

report ISO/TR 5460:1985 Verification principles and methods, published as Swedish standard

SS 2650. The technical report ISO/TR 5460 was withdrawn in 2013, but the Swedish standard

SS 2650 still exists.

All basic definitions of tolerance zones, single features, etc., can be found in ISO 1101 Geometrical

tolerances – Tolerances of form, orientation location and run-out.

This version differs from issue 2 in that the reference to STD 112-0003 in the section “Orientation” and in

section 1 “Scope and field of application” has been changed to ISO 1101. Text has also been added in

the section “Orientation” stating that the technical report ISO/TR 5460 was withdrawn in 2013.

Contents

1 Scope and field of application ......................................................................................................... 2

2 Definitions of concepts..................................................................................................................... 2

3 Indication ........................................................................................................................................... 5

4 Measuring principles – measuring-technical rules, system description and examples ........... 5 4.1 Measuring-technical rules ................................................................................................................... 5 4.2 System description .............................................................................................................................. 6 4.3 Examples of the system ...................................................................................................................... 7

5 Guidelines for selecting measuring principle .............................................................................. 11 5.1 Form tolerances ................................................................................................................................ 12 5.2 Orientation tolerances ....................................................................................................................... 13 5.3 Location tolerances ........................................................................................................................... 14 5.4 16

6 Definitions of measuring principles .............................................................................................. 18 6.1 Form tolerances ................................................................................................................................ 18 6.2 Orientation tolerances ....................................................................................................................... 21 6.3 Location tolerances ........................................................................................................................... 29 6.4 Run-out tolerances ............................................................................................................................ 37

7 Reference to this standard ............................................................................................................. 41


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1 Scope and field of application

The tolerance definitions used in this standard are defined in ISO 1101.

Geometrical tolerances shall, together with measuring principles, be specified with regard to the functional

requirements. Manufacturing and inspection requirements may also influence the way in which the

geometrical tolerances are specified and which measuring principles are chosen.

The purpose of the measuring principles is partly to provide fundamental ways of evaluating that better

can reflect the functional requirements and/or allow a simpler evaluation than that of the fundamental

tolerance definition, and partly to obtain an unambiguous interpretation when implementing different

geometrical tolerances in practice. ISO 1101 does not specify any procedure for evaluating tolerance

zones, which is necessary in order for a tolerance to be unambiguous and for the verification of it to be

repeatable.

The choice of measuring principle affects the measuring result.

The specification of geometrical tolerances together with the measuring principle does not mean that

there is a particular measuring or inspection method that must be used when manufacturing. However,

the specified measuring principle is decisive in case of dispute and thus takes precedence over the

theoretical definitions that can be found in ISO 1101.

The system of measuring principles can be summarized as follows:

– Normally, the measuring principle shall be indicated on the drawing. If no measuring principle is

specified, a measuring principle in accordance with the tolerance definition in ISO 1101 applies (this

means measuring principle 1 by default).

– In this standard, measuring principle refers to fundamental ways of evaluating the tolerance

requirement.

– All measuring principles with a number higher than 1 (2, 3, 4, etc.) are simplified measuring principles

and do not comply with the requirements in accordance with the tolerance definition. However, a

simplified measuring principle can better correspond to the function requirements than the tolerance

definition does.

– The specified measuring principle means that this principle is decisive for the interpretation of the

tolerance requirement.

– By specifying measuring principles, the geometrical tolerances can be connected to more functionally

correct and/or simpler, and thus more economical, methods of inspection.

2 Definitions of concepts

Feature

Portion of a part, such as a plane, a hole, etc.

Actual feature

Physical real feature on a part.

Comment: Generating lines, cylinder surfaces and planes are examples of actual features.

Abstract feature

An unreal feature made from one or several real surfaces.

Comment: Axes, symmetry planes and symmetry lines are examples of abstract features.


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Generating line

A straight line on the surface of a body, in the longitudinal direction of the body.

Comment: A generating line on a cylindrical feature is parallel to the axis of the feature.

Cylinder surface

The surface of a cylindrical feature, such as a shaft or a hole.

Comment: A cylinder surface consists of generating lines.

Parallel lines and surfaces

Straight lines and flat surfaces with equal distance between them.

Comment: Please note that the concept “parallel” is only used for straight lines and flat surfaces. See also

the term Equidistant lines and surfaces.

Equidistant lines and surfaces

Lines and surfaces with the same distance between them, but of another geometrical shape than straight

lines and flat surfaces.

Comment: See also the term Parallel lines and surfaces.

Measuring principle

Interpretation of a tolerance by describing principal origins for measuring a specific geometrical

characteristic.

Comment: One and the same measuring principle, e.g. verification of form by evaluating the diameter

variation with two-point measurement, can be accomplished with one or several measuring methods and

measuring devices.

Measuring method

Realization of a measuring principle in practical application by using various equipments and procedures.

Tangent plane

An imaginary plane of the theoretically exact geometric form which is tangent to an actual plane so that a

stable position for the tangent plane is obtained.

Comment: At least three contact points are required in order to obtain a stable position.

Superimposed plane

An imaginary plane of the theoretically exact geometric form which is tangent to an actual plane so that

the distance between the tangent plane and the actual plane is as small as possible at the point where

this distance is at its maximum.

Comment: Superimposed planes are used to simulate contact between two planes where there is no

stable position for a tangent plane. A superimposed plane can have one contact point.

Tangent line

An imaginary line which is tangent to an actual line so that a stable position for the tangent line is

obtained.

Comment: At least two contact points are required in order to obtain a stable position.

Superimposed line

An imaginary line which is tangent to an actual line so that the distance between the tangent line and the

actual line is as small as possible at the point where this distance is at its maximum.

Comment: Superimposed lines are used to simulate contact between two lines where there is no stable

position for a tangent plane. A superimposed plane can have one contact point.

Least squares method, LS

A mathematical calculation method to adapt a feature of the theoretically exact geometric form to a

number of actual measuring points.


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Comment: With the least squares method, the associated feature is calculated so that the sum of the

squares of the deviation between individual measuring points from the associated feature is the least

possible. Calculation of an associated feature by the least squares method is a measuring principle which

can be applied to all geometrical features.

Maximum inscribed cylinder, MI

The maximum cylinder of the theoretically exact geometric form that can be contained in an internal

actual cylinder.

Comment: Evaluation of an internal cylinder as the maximum inscribed cylinder is a measuring principle

that can be applied via mechanical measuring equipment, or by calculation based on individual measuring

points on the actual cylinder. The maximum inscribed cylinder function constitutes contact feature in an

internal cylinder.

The two-dimensional equivalence to the maximum inscribed cylinder is the maximum inscribed circle.

Minimum circumscribed cylinder, MC

The minimum cylinder of the theoretically exact geometric form that can be placed around an external

actual cylinder.

Comment: Evaluation of an external cylinder as the minimum circumscribed cylinder is a measuring

principle that can be applied via mechanical measuring equipment, or by calculation based on individual

measuring points on the actual cylinder. The minimum circumscribed cylinder function constitutes contact

feature on an external cylinder.

The two-dimensional equivalence to the minimum circumscribed cylinder is the minimum circumscribed

circle.

Minimum zone, MZ

The minimum distance between two geometrically perfect features in which a given feature can be

contained.

For axes, it is the minimum cylinder of geometrically perfect shape in which the entire axis can be

contained.

Comment: For form tolerances, the minimum zone is the applicable tolerance in accordance with the

tolerance definition.

Two-point measurement

Measurement of a dimension when the measurement is made as the distance between two points,

situated opposite each other, for a dimension relating to external or internal surfaces in the same plane.

Comment: Measuring the diameter of a sphere with a micrometer is an example of two-point

measurement. By measuring the dimensional variation with a number of two-point measurements, certain

types of form deviations can be detected.

Three-point measurement

Measurement of a round object where the measurement is made as a diameter on a circle which passes

through three points on the object.

Comments: Often a standard is required for setting purposes, e.g. if the measurement is made with two

contact points and one measuring point for instance when using a V-yoke and a dial indicator to measure

out-of-roundness. Also internal measurements with a three-point micrometer refer to three-point

measurement. A lobed form of triangular shape can be detected with three-point measurement.


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3 Indication

The measuring principles are indicated with the symbol MP 1, MP 2, MP 3, or MP 4 and stated next to the

tolerance frame, see example in figure 1. This indication replaces the previous indication of measuring

principles using Roman numerals in the tolerance frame.

MP 2

MP 1 MP 3

MP 2

MP 1

MP 3

Figure 1

4 Measuring principles – measuring-technical rules, system description and examples

4.1 Measuring-technical rules

General measuring-technical rule

The general rule is that measuring of geometrical requirements shall be carried out in such a way that

the result of the measurement is influenced only by the geometrical shape of the toleranced feature and

by the geometrical shape of the specified datums. In other words, other features must not be used as

“auxiliary datums” or similar since this can affect the measuring result. Therefore, it is important to

specify alignment surfaces and similar as datum features when this is actually required.

Tolerance zone extension

Unless otherwise specified, the tolerance applies to the entire extension of the actual feature, excluding

an edge zone of 0,01 x the length of the feature, where sections pointing downwards are not included.

Surface defects such as burrs and similar are not covered by the geometrical tolerance.

See examples in figures 2 - 3.


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10 45

0,1

MP 1

10

65

0,1

MP 1

Figure 2 Figure 3

The straightness tolerance applies to the

specified area, gauge length 45.

The straightness tolerance applies to the entire

feature. However, “negative” deviations, that is

downward relief, within the area 0,01 x 65 on

each side are not included. Upward-directed

material peaks that cannot be referred to as

surface defects shall be included even if they are

within the edge zone.

Measuring force

Geometrical tolerances apply with the theoretical measuring force 0. Unless otherwise specified, the

maximum measuring force at inspection with indicating instrument is 1 N.

When fixed measuring devices such as function gauges are used at the inspection, the measuring force

is given by the intrinsic mass of the gauge. If it can be assumed that the measuring force can influence

the measuring result to a non-negligible degree, the effect of the measuring force’s influence shall - in

both cases - be recalculated with this in mind.

For soft objects, non-contact measurement is recommended.

4.2 System description

The basic structure below is valid regardless to which tolerance symbol the measuring principle has

been stated.

Measuring principle 1 = The evaluation shall comply with the tolerance definition as per ISO 1101.

The principle can normally be complied with by using computerized or mechanical measuring methods.

Measuring principle 1 means that form deviations are included in the tolerance limitation for both actual

and abstract features regardless of tolerance type. This measuring principle is suitable for many form

requirements and also for run-out requirements. It is also suitable for positional and orientation

tolerances when tolerances apply to an actual feature.

Measuring principle 2 = Evaluation of all features shall be made according to the least squares (LS)

method. This principle requires computer evaluation.

Measuring principle 2 provides a quick measurement in computerized equipment which also often has a

high repeatability.

However, the measuring principle is often not correct functionally, unless it is a question of slender

parts, which take the shape of the mating part when assembled.


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No form deviations are included for this measuring principle other than for form tolerances.

Measuring principle 3 = Evaluation shall be made with actual contact features. The principle can

normally be complied with by using computerized or mechanical measuring methods.

Measuring principle 3 is often the most functionally correct definition. Note that this measuring principle

corresponds to measuring principle 1 in the previous Volvo standard STD 5062,2E if the tolerance is

orientation and location tolerances for an abstract feature. It is thus important to specify this principle for

such function requirements where measuring principle 1 was previously indicated, or where no

indication of measuring principle was previously made if conformity between old and new drawings shall

be obtained.

No form deviations are included for this measuring principle, other than for form tolerances.

Measuring principle 4 and higher = Evaluation adapted to shop-floor measurements. The principle

can normally be complied with by using mechanical measuring methods, but in some cases

computerized evaluations can also be used.

Different measuring principles can be combined.

4.3 Examples of the system

4.3.1 Examples for form tolerance

Ø 2

5 h

7

0,01

Figure 4 Roundness requirement Figure 5 Actual appearance

Measuring principle 1: The circumference in every cross-section shall be contained between two

concentric circles a radial distance 0,01 apart.

When verifying in accordance with measuring principle 1, the centre of these two circles is determined

according to the MZ method, the centre giving the least possible distance between the tolerance circles.

Figure 6 Roundness according to measuring principle 1


concentric circles a radial distance 0,01 apart. The tolerance circles are concentric with a median circle

calculated according to the least squares (LS) method.

When verifying in accordance with measuring principle 2, the centre of a median circle is calculated with

the LS method and, on the basis of the centre of this circle, the radial distance between two tolerance

circles containing the circumference is determined.

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concentric circles a radial distance 0,01 apart. The tolerance circles are concentric with the minimum

circumscribed circle.

When verifying in accordance with measuring principle 3, the centre of the minimum circumscribed

circle is determined according to the MC method and, on the basis of the centre of this circle, the radial

distance between two tolerance circles containing the circumference is determined.

Note: If the tolerance refers to an internal circle, use instead the maximum inscribed circle according to the MI

method.


4.3.2 Examples for orientation tolerance

Ø 25 h7 Ø 0,05 A

A

Figure 9 Perpendicularity requirement Figure 10 Actual appearance

Measuring principle 1: The axis, formed by the centre points for all sections, shall be contained within a

cylinder of diameter 0,05. The tolerance cylinder is perpendicular to datum feature A.

When verifying in accordance with measuring principle 1, the centre of the requisite number of sections

is determined according to the MZ method, and the diameter of the cylinder perpendicular to datum

feature A circumscribing these centre sections is determined.


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Figure 11 Perpendicularity according to measuring principle 1

Measuring principle 2: The axis of a median cylinder determined according to the least squares method

shall be contained within a cylinder of diameter 0,05 mm. The tolerance cylinder is perpendicular to

datum feature A.

When verifying in accordance with measuring principle 2, the toleranced feature is measured as a

median cylinder and the perpendicularity deviation for the axis of the median cylinder is evaluated.


Measuring principle 3: The axis of the minimum circumscribed cylinder shall be contained within a

cylinder of diameter 0,05 mm. The tolerance cylinder is perpendicular to datum feature A.

When verifying in accordance with measuring principle 3, the toleranced feature is evaluated as

circumscribed cylinder and the perpendicularity deviation of the axis of the circumscribed cylinder is

evaluated.

Note: If the tolerance refers to an internal cylinder, use the maximum inscribed cylinder instead.


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4.3.3 Examples for positional tolerance

Ø 25 h7 Ø 0,1 C

A

B C

25 15

B A

Figure 14 Positional requirement Figure 15 Actual appearance

Measuring principle 1: The axis, formed by the centre points for all sections, shall be contained within a

cylinder of diameter 0,1 mm. The tolerance cylinder is perpendicular to datum feature A and situated in

the theoretically exact position in relation to datum features B and C.

When verifying in accordance with measuring principle 1, the centre for the requisite number of sections

is determined according to the MZ method and the position of these sections is evaluated. The centre of

all sections shall be within tolerance in order for the entire axis to be within the tolerance cylinder.

25

Figure 16 Position according to measuring principle 1

Measuring principle 2: The axis of a median cylinder determined according to the least squares method

shall be contained within a cylinder of diameter 0,1 mm. The tolerance cylinder is perpendicular to

datum feature A and situated in the theoretically exact position in relation to datum features B and C.

When verifying in accordance with measuring principle 2, the toleranced feature is measured as a

median cylinder and the positional deviation for the axis of the median cylinder is evaluated.


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25


Measuring principle 3: The axis of the minimum circumscribed cylinder shall be contained within a

cylinder of diameter 0,1 mm. The tolerance cylinder is perpendicular to datum feature A and situated in

the theoretically exact position in relation to datum features B and C. When verifying in accordance with

measuring principle 3, the toleranced feature is measured as circumscribed cylinder and the positional

deviation for the axis of the circumscribed cylinder is evaluated.

Note: If the tolerance refers to an internal cylinder, use maximum inscribed cylinder instead.

25


5 Guidelines for selecting measuring principle

The following matrix is for guidance in selecting measuring principle. It gives general recommendations

for selecting measuring principles and does not contain any clear limits of what is considered low or

high requirements. The aim of the matrix is only to provide support in the form of general guidelines for

how the different measuring principles are intended to be used.


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5.1 Form tolerances

Tolerance MP 1

In accordance

with the tole-

rance definition

MP 2

Mean value

evaluation [LS]

MP 3

Actual contact

features

MP 4 and higher

Adapted to production,

verified during production.

Often used if the process is

stated and thus the poss-

ible types of deviations are

known

Straightness

For generating line For high requirements, as for bearing fits and the like

Slender parts which take the shape of the mating part and for generators with low to medium requirements

For sealing surfaces and stable contact faces

For axis When the maxi-mum material principle can be permitted

For axes with low to medium requirements

For cylinder axes where sealing requirements are important

For verification of bar materials, etc.

Flatness Mating sur-faces, for high form require-ments, and for median planes where the maxi-mum material principle can be allowed

Slender flange which is connecting plane and takes the shape of the mating part when used, and for contact surfaces with low to medium form requirements

Sealing surfaces and contact faces with high requirements

Roundness For high requirements, as for bearing fits and the like

Slender parts which take the shape of the mating part and for parts with low requirements

For parts where high sealing requirements are important

For shop-floor inspection where the type of round-ness deviation is known

Cylindricity For high requirements, as for bearing fits and the like

Slender parts that take the shape of the mating part and for parts with low requirements

For parts where high sealing requirements are important

For shop-floor inspection where the type of cylind-ricity deviation is known

Profile of any line When checking against a digital shape model

Not recommended When checking against a profile template

Profile of any surface When checking against a digital shape model

Not recommended When checking against a digital shape model

For shop-floor inspection


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5.2 Orientation tolerances

Tolerance MP 1

In accordance

with the tole-

rance definition

MP 2

Mean value

evaluation [LS]

MP 3

Actual contact

features

MP 4 and higher






known

Parallelism


For low to medium requirements

For parts with high requirements on parallelism such as bearing fits and the like

Parallelism

For plane For high requirements on parallelism when the flatness requirements are not specified separately

For slender surfaces which take the shape of the mating part when used, and for surfaces with low to medium high requirements

For contact surfaces with medium to high requirements and where flatness requirements are specified separately, and sealing surfaces where flatness requirements are specified separately

For slender surfaces which take the shape of the mating part when used, and where the limitation of the thickness variation is a primary function requirement, e.g. slender washers

Perpendicularity



For parts with high requirements on perpendicularity, such as bearing fits and the like

For plane For high re-quirements on perpendicularity when the flat-ness require-ments are not specified separately

For slender surfaces which take the shape of the mating part when used, and for surfaces with low to medium requirements



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Tolerance MP 1

In accordance

with the tole-

rance definition

MP 2

Mean value

evaluation [LS]

MP 3

Actual contact

features

MP 4 and higher






known

Angularity



For parts with high angularity requirements concerning fits

Angularity

For plane For high re-quirements on angularity when the flatness requirements are not specified separately



5.3 Location tolerances

Tolerance MP 1

In accordance

with the tole-

rance definition

MP 2

Mean value

evaluation [LS]

MP 3

Actual contact

features

MP 4 and higher






known

Position

For centre point in a plane

When the maxi-mum material principle can be permitted for circle

For circles with low positional tolerance requirements

For circles with high positional tolerance requirements

For centre point in a sphere

Not recommended

For spheres with low to medium requirements on positional tolerance

For spheres with high requirements on positional tolerance


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Tolerance MP 1

In accordance

with the tole-

rance definition

MP 2

Mean value

evaluation [LS]

MP 3

Actual contact

features

MP 4 and higher






known


For axes with low requirements on positional tole-rances, e.g. screw holes, and for clearance dia-meters, oil ducts etc.

For fits with high requirements on positional tolerances, e.g. bearing races

For plane For high requirements on positional tolerance when flatness requirements are not specified separately


For contact surfaces with medium high to high requirements and where flatness requirements are specified separately, and sealing surfaces where flatness requirements are specified separately

Position of any profile

When checking against a digital shape model

Not recommended When checking against a profile template

Position of any surface

When checking against a digital shape model

Not recommended When checking against a surface template

Concentricity If the maximum material principle can be permitted for a circle

For circles with low concentricity requirements

For circles with high concentricity requirements

For shop-floor inspection where the limitation of variation in edge distance is a primary functional requirement

Coaxiality When the maximum material principle can be permitted

For axes with low requirements on coaxiality, e.g. screw holes, and for clearance diameters, oil ducts, etc.

For fits with high requirements on coaxiality, e.g. bearing races


Symmetry


For axes with low requirements on symmetry, e.g. screw holes, and for clearance diameters, oil ducts, etc.

For fits with high requirements on symmetry



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Tolerance MP 1

In accordance

with the tole-

rance definition

MP 2

Mean value

evaluation [LS]

MP 3

Actual contact

features

MP 4 and higher






known

For median plane When the maxi-mum material principle can be permitted

For median planes with high requirements on symmetry, at clearance, etc.

For median planes with high requirements on symmetry and fit function, e.g. key ways


5.4 Run-out tolerances

Tolerance MP 1

In accordance

with the tole-

rance definition

MP 2

Mean value

evaluation [LS]

MP 3

Actual contact

features

MP 4 and higher






known

Circular run-out

Radial For general radial run-out requirements

Use concentricity instead

Use concentricity instead


Axial For general axial run-out requirements

For low axial run-out requirements where the design of the part requires measuring with measuring machine

For low axial run-out requirements where the design of the part requires measuring with measuring machine and where the resulting run-out on the mating part is functionally essential

For shop-floor inspection where the type of round-ness deviation on datums is known

Total run-out

Radial For general radial run-out requirements when only measuring one section at a time is not enough

Use coaxiality instead

Use coaxiality instead



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Tolerance MP 1

In accordance

with the tole-

rance definition

MP 2

Mean value

evaluation [LS]

MP 3

Actual contact

features

MP 4 and higher






known

Axial For high requirements on axial total run-out when flatness requirements are not specified separately



For shop-floor inspection where the type of round-ness deviation on datums is known


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6 Definitions of measuring principles

The various measuring principles for different geometrical tolerances are defined in the table below.

The abbreviation t refers to the size of the tolerance concerned in mm.

6.1 Form tolerances

Geometrical tolerances Measuring

principle

Definition

Straightness

Straightness of a

generating line

1 The generating line shall be contained between two parallel

lines a distance t apart.

" 2 The generating line shall be contained between two parallel

lines a distance t apart. These two lines are parallel with a

median line, calculated according to the least squares (LS)

method.


lines a distance t apart. These two lines are parallel with a line

tangent to the generating line.


lines a distance t apart. These two lines are parallel with an

alignment line through two points as far apart as possible on

the generating line.

Straightness of an axis,

cylindrical tolerance zone

1 The axis shall be contained in a cylinder of diameter t.

” 2 The axis shall be contained in a cylinder of diameter t. The size

and orientation of the tolerance cylinder is calculated as a

median cylinder according to the least squares (LS) method,

containing the centre points of all sections. The sections are

calculated as median circles according to the least squares

(LS) method.

“ 3 The axis shall be contained in a cylinder of diameter t. The axis

of toleranced features consists of a line passing through the

centre points of all the sections. These centre points are set

according to the MC method (minimum circumscribed cylinder)

for sections on an external diameter and according to the MI

method (maximum inscribed cylinder) for sections on an

internal diameter.

" 4 The axis shall be contained in a cylinder of diameter t. The

radial difference when rotating with support against two

tangent points is considered as the size of the tolerance

cylinder.


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principle

Definition

Flatness

Flatness 1 The toleranced plane shall be contained between two parallel

planes a distance t apart.

" 2 The toleranced plane shall be contained between two parallel

planes a distance t apart. These two planes are parallel to a

median plane, calculated according to the least squares (LS)

method.

Flatness 3 The toleranced plane shall be contained between two parallel

planes a distance t apart. These two planes are parallel to a

plane tangent to the toleranced one.


planes a distance t apart. These two planes are parallel to an

alignment plane through three points as far apart as possible

on the toleranced plane.

Roundness

Roundness 1 The circumference in every cross-section shall be contained

between two concentric circles a radial distance t apart.

" 2 The circumference in every cross-section shall be contained

between two concentric circles a radial distance t apart. These

two circles are also concentric with a median circle calculated

according to the least squares (LS) method.

" 3 The circumference in every cross-section shall be contained

between two concentric circles a radial distance t apart. These

two circles are also concentric with a circle determined by the

contact points, the minimum circumscribed circle for an

external circle is set according to the MC method, and the

maximum inscribed circle for an internal circle is set according

to the MI method.

" 4 The diameter variation in every cross-section, measured with

two-point measurement, may amount to maximum twice the

stated tolerance t.

" 5 The diameter variation in every cross-section, measured with

three-point measurement and with 120° between the

measurement points, may amount to maximum twice the

stated tolerance t.

Cylindricity

Cylindricity 1 The whole cylinder surface shall be contained between two

coaxial cylinders a radial distance t apart.

" 2 The whole cylinder surface shall be contained between two

coaxial cylinders a radial distance t apart. In addition, these

two cylinders are also coaxial with a median cylinder calculated

according to the LS method.


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principle

Definition

" 3 The whole cylinder surface shall be contained between two

coaxial cylinders a radial distance t apart. These two cylinders

are also coaxial with a cylinder determined by the contact

points, the minimum circumscribed circle for an external

diameter is set according to the MC method and the maximum

inscribed circle for an internal circle is set according to the MI

method.

“ 4 The diameter variation over the whole cylinder, measured with

two-point measurement, may amount to maximum twice the

stated tolerance t.

Cylindricity 5 The diameter variation over the whole cylinder, measured with

three-point measurement and with 120° between the

measurement points, may amount to maximum twice the

stated tolerance t.

Profile of any line

Profile of any line 1 The profile shall be contained between two equidistant lines

tangent to all circles of diameter t, and whose centres lie on a

line of the theoretically exact geometric form. Measurement

against a digital shape model, where a theoretical profile is

fitted against the measured points, belongs to this measuring

principle.

" 2 The measuring principle presupposes that features can be

created with the least squares (LS) method. Such features

exist normally only for very simple profiles of lines. This is why

measuring principle 2 is not recommended.

" 3 The profile shall be contained between two equidistant lines

tangent to all circles of diameter t, and whose centres lie on a

line of the theoretically exact geometric form. These two

equidistant lines are equidistant to a line tangent to an actual

profile of the theoretically exact geometric form.

Profile of any surface

Profile of any surface 1 The surface shall be contained between two equidistant

surfaces tangent to all circles of diameter t, and whose centres

lie on a surface of the theoretically exact geometric form.

Measurement against a digital shape model, where the

theoretical surface is fitted against measured points, belongs to

this measuring principle.

“ 2 This measuring principle presupposes that features can be

created with the least squares (LS) method. Such features

exist normally only for very simple profiles of surfaces. This is

why measuring principle 2 is not recommended.


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principle

Definition

" 3 The surface shall be contained between two equidistant

surfaces tangent to all spheres of diameter t, and whose

centres are on a surface of the theoretically exact geometric

form. These two equidistant surfaces are equidistant to a

surface tangent to an actual surface of the theoretically exact

geometric form.

“ 4 Deviations in profile of surface are considered as a deviation in

profile of line in two directions, at a 90° angle to each other.

The maximum distance between surface and profile template

is considered surface profile deviation.

6.2 Orientation tolerances


principle

Definition

Parallelism

Parallelism of a line in

relation to a datum line, in

a plane

1 In a projection plane, the line shall be contained between two

parallel lines a distance t apart. These two tolerance lines are

parallel to the datum feature. The datum line is set as tangent

line if it consists of a generating line and as axis for the

maximum inscribed cylinder or the minimum circumscribed

cylinder if it consists of an axis for an internal or external

diameter respectively.

” 2 In a projection plane, the line shall be contained between two


parallel to the datum line. The toleranced line and the datum

line are calculated as median features according to the least

squares (LS) method.

" 3 In a projection plane, the line shall be contained between two


parallel to the datum line. The datum line is set as the tangent

line if it consists of a generating line and as an axis for the

maximum inscribed cylinder and the minimum circumscribed




relation to a datum line in

all directions, cylindrical

tolerance zone

1 The line shall be contained in a cylinder of diameter t. This

cylinder is parallel to the datum line. The toleranced line is

calculated using the required number of centre sections in a

cylinder. These centres are set as centres for circles according

to the minimum zone (MZ) method. The datum line is set as an

axis for the maximum inscribed cylinder or the minimum

circumscribed cylinder if it consists of an axis for an internal or

external diameter respectively.


Issue 3 (41)


principle

Definition

" 2 The line shall be contained in a cylinder of diameter t. This

cylinder is parallel to the datum line. The toleranced line is

calculated as the median line of the cylinder according to the

least squares (LS) method. The datum line is calculated as the

axis for the median cylinder according to the least squares (LS)

method.

“ 3 The line shall be contained in a cylinder of diameter t. This

cylinder is parallel to the datum line. The toleranced line is set

as axis for the maximum inscribed cylinder for a hole and as

minimum circumscribed cylinder for a shaft according to the MI

and MC method respectively. The datum line is set as the

maximum inscribed cylinder for a hole and as the minimum

circumscribed cylinder for a shaft according to the MI and MC

method respectively.


relation to a datum plane

1 The line shall be contained between two parallel planes a

distance t apart. These two tolerance planes are parallel to the

datum plane. The toleranced line is calculated using the

required number of centre sections in a cylinder. These centres

are set as centres for circles according to the minimum zone

(MZ) method. The datum plane is set as tangent plane.

" 2 The line shall be contained between two parallel planes a

distance t apart. These two tolerance planes are parallel to the

datum plane. The toleranced line and the datum plane are

calculated as median features according to the least squares

(LS) method.


cylinder is parallel to the datum plane. The toleranced line is

set as axis for the maximum inscribed cylinder for a hole and

as the minimum circumscribed cylinder for a shaft according to

the MI and MC method respectively.

The datum plane is set as tangent plane.

Parallelism of a surface in

relation to a datum line

1 The toleranced plane shall be contained between two parallel

planes a distance t apart. These two tolerance planes are

parallel to the datum line. The datum line is set as tangent line

if it consists of a generating line and as axis for the maximum

inscribed cylinder or the minimum circumscribed cylinder if it

consists of an axis for an internal or external diameter

respectively.



parallel to the datum line. The toleranced plane and the datum

line are calculated as median features according to the least



Issue 3 (41)


principle

Definition



parallel to the datum plane. The toleranced plane is set as

tangent plane. The datum line is set as tangent line if it

consists of a generating line and as axis for the maximum

inscribed cylinder or the minimum circumscribed cylinder if it


respectively.


relation to a datum

surface



parallel to the datum plane. The datum plane is set as tangent

plane.

" 2 A toleranced plane shall be contained between two parallel


parallel to the datum plane. The toleranced plane and the

datum plane are calculated as median features according to

the least squares (LS) method.

“ 3 The toleranced plane shall be contained between two parallel


parallel to the datum plane. The toleranced plane and the

datum plane are set as tangent planes.


relation to a datum

surface

4 The dimensional variation, measured with two-point measure-

ment, between the toleranced plane and the datum plane may

amount to maximum t. This measuring principle is applicable to

plane-parallel surfaces where two-point measurement can be

applied.

Perpendicularity

Perpendicularity of a line

in relation to a datum line



perpendicular to the datum feature. The datum line is set as

tangent line if it consists of a generating line and as an axis for

the maximum inscribed cylinder or the minimum circumscribed





perpendicular to the datum line. The toleranced line and the

datum line are calculated as median features according to the

least squares (LS) method.


parallel lines a distance t apart. These two lines are

perpendicular to the datum line. The toleranced line and the

datum line are set as tangent lines if they consist of generating

lines and as axes for the maximum inscribed cylinder or the

minimum circumscribed cylinder if they consist of axes for an

internal or external diameter respectively.


Issue 3 (41)


principle

Definition

Perpendicularity of an

axis in relation to a datum

plane in all directions,

cylindrical tolerance zone


cylinder is perpendicular to the datum plane. The toleranced

line is set using the required number of centre sections in a

cylinder. These centres are set as centres for circles according

to the minimum zone (MZ) method. The datum plane is set as

tangent plane.



line is set as median line by the least squares (LS) method,

using the required number of centre sections in a cylinder.

These centres are calculated as centres for circles according

to the least squares (LS) method. The datum plane is

calculated as median plane according to the least squares

method.



line is set as axis for the maximum inscribed or the minimum

circumscribed cylinder if they consist of axes for an internal or

an external diameter respectively according to the MI and MC

method respectively. The datum plane is set as tangent plane.

Perpendicularity of a line

in relation to a datum

plane in one direction



perpendicular to the datum feature. The datum plane is set as

tangent plane.



perpendicular to the datum feature. The toleranced line and the

datum line are calculated as median features according to the

least squares (LS) method.



perpendicular to the datum feature. The toleranced line is set

as tangent line if it refers to a generating line. If it refers to an

axis, it is set as axis for the maximum inscribed or the

minimum circumscribed cylinder when the tolerance refers to

an internal or external diameter, according to the MI and the

MC method respectively. The datum plane is set as tangent

plane.


Issue 3 (41)


principle

Definition

Perpendicularity of a

surface in relation to a

datum line


lines a distance t apart. These two tolerance planes are

perpendicular to the datum feature. The datum line is set as

tangent line if it consists of a generating line and as axis for the

maximum inscribed or the minimum circumscribed cylinder if it


respectively.



perpendicular to the datum feature. The toleranced plane and

the datum line are calculated as median features according to




perpendicular to the datum feature. The toleranced plane is set

as tangent plane. The datum line is set as tangent line if it

consists of a generating line and as axis for the maximum

inscribed or the minimum circumscribed cylinder if it consists of

an axis for an internal or external diameter respectively.



datum surface



perpendicular to the datum feature. The datum plane is set as

tangent plane.

Note: If no secondary datum feature is indicated, the part may be

turned around the datum plane to the smallest possible difference in

dimensions.



datum surface




the datum plane are calculated as median features by the least




dimensions.




the datum plane are set as tangent planes.



dimensions.


Issue 3 (41)


principle

Definition

Angularity

Angularity of a line in a

plane in relation to a

datum line



aligned with the specified angle in relation to the datum

feature. The datum line is set as tangent line if it consists of a

generating line and as axis for the maximum inscribed or the

minimum circumscribed cylinder if it consists of an axis for an





feature. The toleranced line and datum line are calculated as

median features according to the least squares (LS) method.




feature. If it refers to a generating line, the toleranced line is set

as tangent line. If it refers to an axis, it is set as axis for the

maximum inscribed or the minimum circumscribed cylinder

according to the MI and MC method respectively.

The datum line is set as tangent line if it consists of a




Angularity in all directions

of an axis in relation to a

datum line


tolerance cylinder is aligned with the specified angle in relation

to the primary datum feature and parallel to the secondary

datum feature. The toleranced line is set using the required

number of centre sections in a cylinder. These centres are set

as centres for circles according to the minimum zone (MZ)

method. The datum line is set as tangent plane if it consists of

an axis and as axis for the maximum inscribed or the minimum



Angularity in all directions

of an axis in relation to a

datum line




datum feature. The toleranced line and datum feature are


(LS) method.


Issue 3 (41)


principle

Definition

” 3 The line shall be contained in a cylinder of diameter t. This



datum feature. The toleranced line is set as the maximum

inscribed or minimum circumscribed cylinder if it consists of an

axis for an internal or external diameter respectively.

The datum line is set as tangent line if it consists of a




Angularity of a line in

relation to a datum

surface



aligned with the specified angle in relation to the primary datum

feature. The datum plane is set as tangent plane.

" 2 In a projection plane, the line shall fit between two parallel lines

a distance t apart. These two tolerance lines are aligned with

the specified angle in relation to the primary datum feature.

Toleranced line and datum plane are calculated as median

features by the least squares (LS) method.



aligned with the specified angle in relation to the primary datum

feature. If it refers to a generating line, the toleranced line is set

as tangent plane. But if it refers to an axis, it is set as axis for

the maximum inscribed cylinder for a hole or the minimum

circumscribed cylinder for a shaft according to the MI and MC

method respectively.

The datum plane is set as tangent plane.

Angularity of a surface in



lines a distance t apart. These two tolerance lines are aligned

with the specified angle in relation to the datum feature. The

datum line is set as tangent line if it consists of a generating

line and as axis for the maximum inscribed or the minimum




turned around the datum line to the smallest possible difference in

dimensions.




planes a distance t apart. These two tolerance lines are


feature. The toleranced plane and the datum line are

calculated as median features by the least squares (LS)

method.



dimensions.


Issue 3 (41)


principle

Definition




feature. The datum line is set as tangent line. The datum line is

set as tangent line if it consists of a generating line and as axis

for the maximum inscribed or the minimum circumscribed





dimensions.


relation to a datum

surface




feature. The datum plane is set as tangent plane.



dimensions.




feature. The toleranced plane and the datum plane are


(LS) method.



dimensions.




feature. The toleranced plane and datum plane are set as

tangent planes.



dimensions.


Issue 3 (41)

6.3 Location tolerances


principle

Definition

Position

Position in all directions

of a point in a plane

1 The toleranced point shall be contained in a circle of diameter

t. The centre point of this tolerance circle is situated in the

theoretically exact position in relation to stated datums. If it is a

centre point, the position of the toleranced features is set as

position for a circle calculated according to the minimum zone

(MZ) method

The datum feature is set as tangent plane, inscribed circle or

cylinder, or circumscribed circle or cylinder, depending on what

the datum feature is made up of.

" 2 The toleranced point shall be contained in a circle of diameter




position for a median circle calculated according to the least

squares (LS) method

The datum feature is calculated as median feature according to


“ 3 The toleranced point shall be contained in a circle of diameter




position for an inscribed or circumscribed circle according to

the MI and MC method respectively.



the datum feature is.


of a point, spherical

tolerance zone

1 The toleranced point shall be contained in a circle of diameter




position for a circle calculated according to the minimum zone

(MZ) method.




“ 2 The toleranced point shall be contained in a sphere of diameter

t. The centre point of this tolerance sphere is situated in the



position for a median sphere calculated according to the least

squares (LS) method




Issue 3 (41)


principle

Definition


of a point, spherical

tolerance zone

3 The toleranced point shall be contained in a sphere of diameter

t. The centre point of this tolerance sphere is situated in the


centre point for an internal sphere, the position of the tole-

ranced feature is set as position for an inscribed sphere

according to the MI method and if it is an external sphere, it is

set as position for a circumscribed sphere according to the MC

method.




Position of a line in one

direction



symmetrically disposed around the theoretically exact position

in relation to the datum feature. The reference feature is set as

tangent plane, inscribed circle or cylinder or circumscribed

circle or cylinder depending on what the datum feature is.




in relation to the datum feature. The toleranced line is

calculated as median line according to the least squares

method if it consists of a generating line and as an axis for a

median cylinder according to the least squares method if it

consists of a cylinder axis.



“ 3 In a projection plane, the line shall be contained between two



in relation to the datum feature. The toleranced line is set as

tangent line if it consists of a generating line and as the

maximum inscribed cylinder or minimum circumscribed

cylinder if it consists of an internal or external cylinder

respectively.


cylinder, or circumscribed circle or cylinder depending on what



Issue 3 (41)


principle

Definition

Position of a line in all

directions

1 The line shall be contained in a cylinder of diameter t. The axis

of this tolerance cylinder lies in the theoretically exact position

in relation to the datum feature.


cylinder, or circumscribed circle or cylinder depending on what


" 2 The line shall be contained in a cylinder of diameter t. The axis



The toleranced feature consists of the axis for a cylinder

calculated according to the least squares method. The datum

feature is set as median feature according to the least squares

(LS) method.

Position of a line in all

directions

3 The line shall be contained in a cylinder of diameter t. The axis



The toleranced feature consists of the axis for a cylinder set as

the maximum inscribed cylinder or the minimum circumscribed


respectively.

The datum feature is set as tangent plane if it consists of a

plane, as tangent line if it consists of a line, and as the



respectively.

Position of a flat surface

or a median plane 1 The toleranced plane shall be contained between two parallel




The datum feature is set as tangent plane. If the tolerance

consists of a median plane, it is set as median plane for two

planes which have been set as tangent plane for those planes

that make up the datum feature.




in relation to the datum plane.

The toleranced plane and the datum plane are calculated as

median features according to the least squares (LS) method. If

the tolerance consists of a median plane, it is set as median

plane for two planes which have been calculated as median

planes for those planes that make up the datum feature.


Issue 3 (41)


principle

Definition




in relation to the datum plane. The toleranced plane and the

datum plane are set as tangent planes.

If the tolerance consists of a median plane, it is set as median

plane for two planes set as tangent planes for those planes

that make up the datum feature.

Position of any profile

Position of any profile 1 The profile shall be contained between two equidistant lines

enveloping all circles of diameter t, and whose centres lie on a

line of the theoretically exact geometric form and are disposed

in the theoretically exact position. Measurement against digital

shape model, where the position of the measured points is

related to the correct position on the model, belongs to this

measuring principle.

“ 2 This measuring principle presupposes that features can be

created with the least squares method. Such features exist

normally only for very simple profile of lines. This is why


Position of any profile 3 The profile shall be contained between two equidistant lines

enveloping all circles of diameter t, and whose centres lie on a

line of the theoretically exact geometric form and are disposed

in the theoretically exact position. The profile is set against a

line of the theoretically exact geometric form tangent to an

actual profile.

Position of any surface

Position of any surface 1 The surface shall be contained between two equidistant

surfaces enveloping all spheres of diameter t, and whose

centres lie on a surface of the theoretically exact geometric

form and are disposed in the theoretically exact position.

Measurement against digital shape model, where the position

of the measured points is related to the correct position on the

model, belongs to this measuring principle.

" 2 This measuring principle presupposes that features can be

created with the least squares method. Such features exist

normally only for very simple profile of surfaces. This is why


“ 3 The surface shall be contained between two equidistant

surfaces tangent to all spheres of diameter t, and whose

centres lie on a line of the theoretically exact geometric form

and are disposed in the theoretically correct position. The

profile is set against a line of the theoretically exact geometric

form tangent to an actual profile.


Issue 3 (41)


principle

Definition

Concentricity

Concentricity of a point 1 The toleranced point shall be contained in a circle of diameter

t. The centre point of this tolerance circle coincides with the

centre point of the datum. The position of the toleranced

feature is set as the position of a circle calculated in

accordance with the minimum zone (MZ) method.

The datum feature is set as maximum inscribed circle or

minimum circumscribed circle depending on whether it consists

of an internal or external circle.




feature is set as position of a median circle calculated

according to the least squares (LS) method.

The datum feature is calculated as median circle according to





feature and the position of the datum feature are set as

position of the maximum inscribed circle or the minimum

circumscribed circle depending on whether it applies to an

internal or external circle.

Concentricity of a point 4 The toleranced point shall be contained in a circle of diameter


centre point of the datum.

The size of the tolerance circle corresponds to the variation in

two-point measurement when measuring the cylinder surface

of the toleranced feature and the datum feature. The variation

is measured in one section.

Coaxiality

Coaxiality of an axis 1 The line shall be contained in a cylinder of diameter t. The axis

of this tolerance cylinder coincides with the datum feature or its

extension. The datum feature is set as the maximum inscribed

cylinder or the minimum circumscribed cylinder depending on

whether it applies to an internal or external cylinder.

If the primary datum consists of a plane and the secondary

datum consists of a cylinder, the primary datum is set as

tangent plane and the secondary datum as the maximum

inscribed cylinder, which is perpendicular to the primary datum

if the secondary datum consists of an internal cylinder and as

minimum circumscribed cylinder, perpendicular to the primary

datum, if the secondary datum consists of an external cylinder.


Issue 3 (41)


principle

Definition

“ 2 The line shall be contained in a cylinder of diameter t. The axis


extension. The toleranced axis is calculated as the axis of a

median cylinder according to the least squares method. The

datum feature is set as the axis of a median cylinder.


datum consists of an internal cylinder, the primary datum is


method and the secondary datum as the maximum cylinder,

perpendicular to the primary datum, that can be inscribed

within the median cylinder of the secondary datum which is

calculated according to the least squares method.


datum consists of an external cylinder, the primary datum is

calculated as median plane by the least squares method and

the secondary datum is calculated by the least squares method

as the minimum cylinder, perpendicular to the primary datum,

that can be circumscribed around the median cylinder of the

secondary datum which is calculated according to the least

squares method.

Coaxiality of an axis 3 The line shall be contained in a cylinder of diameter t. The axis


extension. The toleranced feature is calculated as the axis of a

cylinder set as the maximum inscribed cylinder or the minimum

circumscribed cylinder if it consists of an internal or external

cylinder respectively.

The datum feature is set as the maximum inscribed cylinder or

the minimum circumscribed cylinder depending on whether it

applies to an internal or external cylinder respectively.


datum consists of an internal cylinder, the primary datum is set

as tangent plane and the secondary datum as the maximum

inscribed cylinder, which is perpendicular to the primary datum

if the secondary datum consists of an internal cylinder, and as



" 4 The line shall be contained in a cylinder of diameter t. The axis

of this tolerance cylinder coincides with the datum feature.

The size of the tolerance cylinder corresponds to the variation

in two-point measurement when measuring the cylinder

surface of the toleranced feature and the datum feature. The

variation is measured over the entire length of the feature.


Issue 3 (41)


principle

Definition

Symmetry

Symmetry of an axis 1 In a projection plane, the line shall be contained between two


symmetrically disposed around the datum line or the datum

plane.

If the datum feature consists of a cylinder axis it is set as the

maximum inscribed cylinder or minimum circumscribed

cylinder depending on whether it applies to an internal or

external cylinder respectively.

If the datum consists of a median line, it is set as median line

for two lines set as tangent lines for those lines that make up

the datum feature. If the datum feature consists of a median

plane, it is set as tangent plane for the planes that make up the

datum feature.

“ 2 In a projection plane, the line shall be contained between two



plane.

A toleranced line is calculated as axis for a median cylinder

according to the least squares method if it consists of a

cylinder axis.

If the datum feature consists of a cylinder axis, it is calculated

as median cylinder axis according to the least squares method.

If the datum feature consists of a median line, it is set as

median line for two lines set as median lines for those lines

that make up the datum feature. If the datum feature consists

of a median plane, it is set as median plane for two planes set

as median plane for the planes that make up the datum

feature.

Symmetry of an axis 3 In a projection plane, the line shall be contained between two



plane.

The toleranced feature is set as axis for a cylinder set as the



respectively.

If the datum feature consists of a cylinder axis it is set as


cylinder depending on whether it applies to an internal or

external cylinder respectively.

If the datum feature consists of a median line, it is set as

median line for two lines set as tangent lines for those lines

that make up the datum feature. If the datum feature consists

of a median plane it is set as median plane for two planes set

as tangent plane for those planes that make up the datum

feature.


Issue 3 (41)


principle

Definition




plane.

If the datum feature consists of an axis, the distance variation

between the cylinder surface of a toleranced cylinder and the

cylinder surface of the datum feature, measured by two-point

measurement, is considered as symmetry deviation and must

not exceed the tolerance t.

If the datum feature consists of symmetry plane, the distance

variation between the cylinder surface of a toleranced cylinder

and the cylinder surface of any surfaces constituting the datum

feature, measured by two-point measurement, is considered as

symmetry deviation and must not exceed the tolerance t.

This measuring principle can be regarded as variation in

distance to the edge.

Symmetry of a median

plane


planes a distance t apart. These two toleranced planes are

symmetrically disposed around the datum feature.

The datum feature is set as median plane for two planes set as

tangent planes for those planes that make up the datum

feature.



symmetrically disposed around the datum plane.

The toleranced plane and the datum plane are set as median

planes for the two planes respectively, which in turn are set as

median planes for those planes that make up the toleranced

feature or the datum feature.

Symmetry of a median

plane




The toleranced plane and the datum plane are set as median

planes for two planes respectively, which in turn are set as

tangent planes for those planes that make up the toleranced

feature or the datum feature.




The distance variation between the surfaces forming the

toleranced feature and surfaces forming the datum feature,

measured by two-point measurement, is considered as

symmetry deviation and must not exceed the tolerance t.

The measuring principle can be considered as a variation in

distance to the edge.


Issue 3 (41)

6.4 Run-out tolerances


principle

Definition

Circular run-out

Circular radial run-out 1 The outline in a section shall be contained between two

concentric circles a radial distance t apart. The centre points of

these tolerance circles coincide with the axis of the datum shaft

or its elongation.

The datum feature is set as maximum inscribed cylinder or

minimum circumscribed cylinder depending on whether it

applies to an internal or external circle respectively.



tangent plane and the secondary datum is set as maximum

inscribed cylinder perpendicular to the primary datum if the

secondary datum consists of an internal cylinder, and as

minimum circumscribed cylinder perpendicular to the primary

datum if the secondary datum consists of an external cylinder.

" 2 Not relevant. Use concentricity/coaxiality if measuring principle

2 is required

" 3 Not relevant. Use concentricity/coaxiality if measuring principle

3 is required

Circular radial run-out 4 The outline in a section shall be contained between two

concentric circles a radial distance t apart. The centre points of

these tolerance circles coincide with the axis of the datum shaft

or its elongation.

The datum feature is evaluated by rotation in two 90° V-yokes

if the datum feature consists of two external circles or in a 90°

V-blocks if the datum feature consists of an external cylinder.

If the datum feature consists of internal circles or cylinders it

shall be rotated in a corresponding way with contact with two

points or lines on the datum feature. These contact points/lines

are at a 90° angle to each other.

Circular axial run-out 1 The outline in each cross-section of the same radius on the

surface shall be contained between two concentric circles of

the same radius and an axial distance t apart. The centres of

these tolerance circles coincide with the axis of the datum

feature or its elongation.



applies to an internal or external circle respectively.





secondary datum consists of an internal cylinder, and as




Issue 3 (41)


principle

Definition

“ 2 Each cross-section of the same radius on the surface shall be

contained between two concentric circles of the same radius

and an axial distance t apart. The centres of these tolerance

circles coincide with the axis of the datum shaft or its

elongation.

Each cross-section is calculated as a circular plane according

to the least squares (LS) method.

The datum feature is set as the axis of a median cylinder.


datum consists of an internal cylinder, the primary datum is set

as median plane by the least squares method and the

secondary datum is set as maximum cylinder perpendicular to

the primary datum that can be inscribed in the median cylinder

of the secondary datum, calculated according to the least

squares method.


datum consists of an external cylinder, the primary datum is set

as median plane according to the least squares method and

the secondary datum is calculated according to the least

squares method as the minimum cylinder perpendicular to the

primary datum that can be scribed around the median cylinder

of the secondary datum.

Circular axial run-out 3 Each cross-section of the same radius on the surface shall be

contained between two concentric circles of the same radius

and an axial distance t apart. The centres of these tolerance

circles coincide with the axis of the datum feature or its

elongation.

Each cross-section is set as a circular tangent plane.



applies to an internal or external cylinder respectively.





secondary datum consists of an internal cylinder and as the



“ 4 The outline in each cross-section of the same radius on the

surface shall be contained between two concentric circles of

the same radius and an axial distance t apart. The centres of

these tolerance circles coincide with the axis of the datum

feature or its elongation.


if it consists of two external circles, or in two 90° V-blocks if it

consists of an external cylinder.






Issue 3 (41)


principle

Definition

Total run-out

Total radial run-out 1 The whole cylinder surface shall be contained between two

coaxial cylinders a radial distance t apart. The axis of these

tolerance cylinders coincides with the axis of the datum feature

or its extension.



applies to an internal or external cylinder.




inscribed cylinder, perpendicular to the primary datum if the

secondary datum consists of an internal cylinder, and as a



" 2 Not relevant. Use coaxiality if measuring principle 2 is required.

" 3 Not relevant. Use coaxiality if measuring principle 3 is required.

Total radial run-out 4 The whole cylinder surface shall be contained between two

coaxial cylinders a radial distance t apart. The axis of these

tolerance cylinders coincides with the axis of the datum feature

or its extension.


if it consists of two external circles, or in two 90° V-blocks if it

consists of an external cylinder.





Total axial run-out

Note: This tolerance is

identical to perpendicularity

for a surface with an axis as

datum.



perpendicular to the datum axis.

The datum axis is set as axis for the maximum inscribed

cylinder or the minimum circumscribed cylinder if it consists of

an axis for an internal and external diameter respectively.





secondary datum consists of an internal cylinder, and as the




Issue 3 (41)


principle

Definition




the datum line are calculated as median features according to


The datum shaft is set as axis for a median cylinder.


datum consists of an internal cylinder, the primary datum is


method and the secondary datum as the maximum cylinder

perpendicular to the primary datum that can be inscribed into

the median cylinder of the secondary datum, calculated

according to the least squares method.


datum consists of an external cylinder, the primary datum is


method, and the secondary datum is calculated according to

the least squares method as the minimum cylinder,

perpendicular to the primary datum, to be scribed around the

median cylinder of the secondary datum.

Total axial run-out 3 The toleranced plane shall be contained between two parallel


perpendicular to the datum feature. The toleranced plane is set

as tangent plane.

The datum axis is set as axis for the maximum inscribed

cylinder or the minimum circumscribed cylinder if it consists of

an axis for an internal or external diameter respectively.





secondary datum consists of an internal cylinder, and as the





perpendicular to the datum feature. The datum feature is

evaluated by rotation in two 90° V-yokes if it consists of two

external circles, or in two 90° V-blocks if it consists of an

external cylinder.

If the datum feature consists of internal circles or cylinders, it





Issue 3 (41)

7 Reference to this standard

Reference to this standard on drawings or other engineering design documentation shall be made

through a reference standard or directly with the following note:

MEASURING PRINCIPLES STD 112-0004

measuring principles for geometrical tolerances - volvo · standard std 112-0004 volvo group issue...

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