SIST ISO 4292:1995

Methods for the assessment of departure from roundness -- Measurement by two- and three-point methods

Determines the out-of-roundness by means of two-point measurement (measurement of diameters), by means of three-point measurement, summit (symmetrical or asymmetrical setting), and by means of three-point measurement, rider (symmetrical setting). Suitable for routine or in-process inspection because of the methods specified in ISO 4292 are faster and cheaper (than the procedure in ISO 4291).

Méthodes d'évaluation des écarts de circularité -- Mesurage par les méthodes en deux et trois points

Metode za ugotavljanje odstopka od krožnosti - Dvo- in tritočkovna metoda merjenja

General Information

• Status: Withdrawn
• Publication Date: 31-Oct-1995
• Withdrawal Date: 29-Jan-2015
• ICS: 17.040.20 - Properties of surfaces
• Technical Committee: ISEL - Mechanical elements
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 27-Jan-2015
• Due Date: 19-Feb-2015
• Completion Date: 30-Jan-2015
• Ref Project: ISO 4292:1985 - Methods for the assessment of departure from roundness — Measurement by two- and three-point methods

Standards Content (Sample)

F
Y-
International Standard @ 4292
IYTERNATIONAL ORGANlZAriOh FOR STANPARDIZATION*MEXflYHAPOflHAR OPrAHL43AUL4R fl0 CTAHAAPTM3AUMM.OAGANlSATlON INTERNATIONALE DE NORMALISATION
Methods for the assessment of departure from
roundness - Measurement by two- and three-point
methods
Méthodes d'évaluation des écarts de circularité Mesuraqe par les méthodes wi dec;x et trois points
First edition - 1985-07-15
- UDC 531.717 Ref. No. IS0 4292-1985 (E)
E
Descriptors : metrology, surface condition, roundness measurement, error analysis
- 3
O
E
Price based on 8 pages

---------------------- Page: 1 ----------------------
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of preparing International
Standards is normally carried out through IS0 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, govern-
mental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the IS0 Council. They are approved in accordance with IS0 procedures requiring at
least 75 YO approval by the member bodies voting.
International Standard IS0 4292 was prepared by Technical Committee ISOITC 57,
Me frology and properties of surfaces.
C International Organization for Standardization, 1985 0
Printed in Switzerland

---------------------- Page: 2 ----------------------
IS0 4292-1985 (E)
I NTE R N AT1 O N AL STAN DARD
Methods for the assessment of departure from
roundness - Measurement by two- and three-point
methods
1 Scope and field of application
3.1 two-point measurement : Measurement between
coaxial anvils, one fixed and one moving in the direction of
measurement.
This International Standard specifies methods of numerical
assessment of out-of-roundness determined by the combi-
See figures 1 and 2
nation of two- and three-point measurement :
ai determination by means of two-point measurement
3.2 three-point measurement : Measurement between
(measurement of diameters) :
anvils, two fixed and one moving in the direction of measure-
ment.
bi determination by means of three-point measurement,
summit (symmetrical or asymmetrical setting) : See figures 3 to 8
ci determination by means of three-point measurement,
3.2.1 summit method : A three-point measurement in which
rider (symmetrical setting).
the two fixed anvils are situated on one side and the measuring
anvil is situated on the other side of the workpiece axis in the
Any statement regarding an out-of-round section is incomplete
plane of measurement,
unless the extent and nature of the departures from roundness
are given. Methods for making such descriptions and
See figures 3, 4, 6 and 7.
evaluating them are specified in IS0 4231.
3.2.2 rider method: A three-point measurement in which
For routine or in-process inspection, the procedure specified in
the two fixed anvils are situated on the same side as the
IS0 4291 rnay either be needlessly accurate or the items to be
measuring anvil in the plane of measurement.
inspected may be too large to be accommodated.
See fisures 5 and 8
The methods specified give faster arid cheaper ways of assess-
ing departures from roundness. This assessed value will deviate
3.3 symmetrical (three-point) setting : A setting at which
from the true value. The difference between the measured
the direction of measurement coincides with the bisector angle
value and the true value can be estimated with the help of
between fixed anvils.
tables 2 to 8. assuming that the undulation numbers are known
and of sinusoidal nature. For non-sinusoidal undulations, a
See figures 3, 5, 6 and 8.
theory for estimating such deviations is not yet available.
3.4 asymmetrical (three-point) setting : A setting at
which the direction of measurement constitutes an angle with
the bisector angle between fixed anvils.
2 References
See figures 4 and 7
IS0 4291, Methods for the assessment of departure from
roundness - Measurement of variations in radius.
4 Measurement
IS0 6318, Measurement of roundness -- Terms, definitions
and parameters of roundness.
In order to cover all possible form deviations and numbers of
undulations, a complete measurement should always consist of
one two-point measurement and two three-point measure-
ments at different angles between fixed anvils. In this Inter-
3 Definitions
national Standard, several alternatives are given when choos-
ing angles between fixed anvils (see table 1). The measurement
For the purpose of this International Standard, the definitions
procedures rnay, under certain preconditions, be amplified.
given in IS0 6318 and the following apply.
See tables 2 to 4.
1

---------------------- Page: 3 ----------------------
P
Iii
IS0 4292-1985 (El
Table 1 - Angles between fixed anvils There 15 a limit OP the maximum number of undulations to be
used when selecting F, accordiny to whether the number of
--___
Svrnrnetrical setting Asymmetrical setting
iidulatienç is known and whether this number is an odd or
even value This Drscondition IS shown in tables 2 to 4
Angle hetween
direction of
Angle hetween measurement
Angle between -1
For 90" and 120° settings, the limit is 22, which assumes that a
fixed anvils, 1 fixed anvils, and bisector of
greater number of undulations than this will not have any ap-
fi n anqle between
preciable effect on the factor F'.
fixed anvils,
j fl
For 72" and 108O settings, the limit is determined by the fact
j anri '20
120 60
that for 19 undulations the factor F cannot be determined.
77 and 108" 60 ' I 30'
Factors F for three-point measurement, symmetrical settincj,
are giveri in table 8.
?he corrert~d value of the departure from roundness <1 IS
qive? bv the eqiiation
NOTE ~ When usinq tables 5 to 8
other combinations of çettinq
besides those given !ri tables 2 to 4 can he made
'j
il-
F.
where
1 15 the measured departure from roundness - it is the
6 Measuring conditions and instrument
largest value obtained from the preceding two or three corn-
binatiow of angles received in the required measurements
6.1 Measuring anvil static force
F IS rhe correction facror - it has a value extracted from
tables 2 to 8 las a first approximation, F- may be given a
The static measuring force should not exceed 1 N. The force
value of 2)
should, preferably. be adjustable and set at the lowest value
that will ensure cmtinuous contact between anvil and the sur-
Wher: measuring workpieces with a known even or odd
face being measured
number of undulations, the three-point measurement with
symmetrical setting at 60° angles between fixed anvils may be
For thin-walled workpieces, a high measuring force may affect
used according to table 8. This angle is usefui as it gives
the measuring result. Therefore it is necessary to reduce the
measured values of higher correction factors than the other
force to the minimum value possible.
angles in this International Standard. When using the 6ûo
angle, the measured value shall be corrected with the factor F'
given in table 8.
6.2 Measuring anvils
Depending on the form of the object, the measuring anvil shall
5 Evaluation of measurement errors
be selected from table 9, unless otherwise specified.
Tables 5 to 7 give true factors F- for any given number of
6.3 Fixed anvils
sinusoidal undulations and measuring method.
if the number of sinusoidal undulations ki known, the calcula- Point or line contact shall always be used. The following are
tion of the departure from roundness is made by using the F recommended :
factors directly from tables 5, 6, or 7 as indicated in tables 2, 3,
or 4. - for external measurement: V-support with a small
in the
radius; the median plane of the V-support shall be
It is not possib!e to calculate exactly the departure from round- same plane as the plane of measurement.
ness if the number of undulations is unknown. In these cases a
- for internal measurement : sp
...

SLOVENSKI STANDARD
SIST ISO 4292:1995
01-november-1995
0HWRGH]DXJRWDYOMDQMHRGVWRSNDRGNURåQRVWL'YRLQWULWRþNRYQDPHWRGD
PHUMHQMD
Methods for the assessment of departure from roundness -- Measurement by two- and
three-point methods
Méthodes d'évaluation des écarts de circularité -- Mesurage par les méthodes en deux et
trois points
Ta slovenski standard je istoveten z: ISO 4292:1985
ICS:
17.040.20 Lastnosti površin Properties of surfaces
SIST ISO 4292:1995 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 4292:1995

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SIST ISO 4292:1995
F
Y-
International Standard @ 4292
IYTERNATIONAL ORGANlZAriOh FOR STANPARDIZATION*MEXflYHAPOflHAR OPrAHL43AUL4R fl0 CTAHAAPTM3AUMM.OAGANlSATlON INTERNATIONALE DE NORMALISATION
Methods for the assessment of departure from
roundness - Measurement by two- and three-point
methods
Méthodes d'évaluation des écarts de circularité Mesuraqe par les méthodes wi dec;x et trois points
First edition - 1985-07-15
- UDC 531.717 Ref. No. IS0 4292-1985 (E)
E
Descriptors : metrology, surface condition, roundness measurement, error analysis
- 3
O
E
Price based on 8 pages

---------------------- Page: 3 ----------------------

SIST ISO 4292:1995
Foreword
IS0 (the International Organization for Standardization) is a worldwide federation of
national standards bodies (IS0 member bodies). The work of preparing International
Standards is normally carried out through IS0 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, govern-
mental and non-governmental, in liaison with ISO, also take part in the work.
Draft International Standards adopted by the technical committees are circulated to
the member bodies for approval before their acceptance as International Standards by
the IS0 Council. They are approved in accordance with IS0 procedures requiring at
least 75 YO approval by the member bodies voting.
International Standard IS0 4292 was prepared by Technical Committee ISOITC 57,
Me frology and properties of surfaces.
C International Organization for Standardization, 1985 0
Printed in Switzerland

---------------------- Page: 4 ----------------------

SIST ISO 4292:1995
IS0 4292-1985 (E)
I NTE R N AT1 O N AL STAN DARD
Methods for the assessment of departure from
roundness - Measurement by two- and three-point
methods
1 Scope and field of application
3.1 two-point measurement : Measurement between
coaxial anvils, one fixed and one moving in the direction of
measurement.
This International Standard specifies methods of numerical
assessment of out-of-roundness determined by the combi-
See figures 1 and 2
nation of two- and three-point measurement :
ai determination by means of two-point measurement
3.2 three-point measurement : Measurement between
(measurement of diameters) :
anvils, two fixed and one moving in the direction of measure-
ment.
bi determination by means of three-point measurement,
summit (symmetrical or asymmetrical setting) : See figures 3 to 8
ci determination by means of three-point measurement,
3.2.1 summit method : A three-point measurement in which
rider (symmetrical setting).
the two fixed anvils are situated on one side and the measuring
anvil is situated on the other side of the workpiece axis in the
Any statement regarding an out-of-round section is incomplete
plane of measurement,
unless the extent and nature of the departures from roundness
are given. Methods for making such descriptions and
See figures 3, 4, 6 and 7.
evaluating them are specified in IS0 4231.
3.2.2 rider method: A three-point measurement in which
For routine or in-process inspection, the procedure specified in
the two fixed anvils are situated on the same side as the
IS0 4291 rnay either be needlessly accurate or the items to be
measuring anvil in the plane of measurement.
inspected may be too large to be accommodated.
See fisures 5 and 8
The methods specified give faster arid cheaper ways of assess-
ing departures from roundness. This assessed value will deviate
3.3 symmetrical (three-point) setting : A setting at which
from the true value. The difference between the measured
the direction of measurement coincides with the bisector angle
value and the true value can be estimated with the help of
between fixed anvils.
tables 2 to 8. assuming that the undulation numbers are known
and of sinusoidal nature. For non-sinusoidal undulations, a
See figures 3, 5, 6 and 8.
theory for estimating such deviations is not yet available.
3.4 asymmetrical (three-point) setting : A setting at
which the direction of measurement constitutes an angle with
the bisector angle between fixed anvils.
2 References
See figures 4 and 7
IS0 4291, Methods for the assessment of departure from
roundness - Measurement of variations in radius.
4 Measurement
IS0 6318, Measurement of roundness -- Terms, definitions
and parameters of roundness.
In order to cover all possible form deviations and numbers of
undulations, a complete measurement should always consist of
one two-point measurement and two three-point measure-
ments at different angles between fixed anvils. In this Inter-
3 Definitions
national Standard, several alternatives are given when choos-
ing angles between fixed anvils (see table 1). The measurement
For the purpose of this International Standard, the definitions
procedures rnay, under certain preconditions, be amplified.
given in IS0 6318 and the following apply.
See tables 2 to 4.
1

---------------------- Page: 5 ----------------------

SIST ISO 4292:1995 P
Iii
IS0 4292-1985 (El
Table 1 - Angles between fixed anvils There 15 a limit OP the maximum number of undulations to be
used when selecting F, accordiny to whether the number of
--___
Svrnrnetrical setting Asymmetrical setting
iidulatienç is known and whether this number is an odd or
even value This Drscondition IS shown in tables 2 to 4
Angle hetween
direction of
Angle hetween measurement
Angle between -1
For 90" and 120° settings, the limit is 22, which assumes that a
fixed anvils, 1 fixed anvils, and bisector of
greater number of undulations than this will not have any ap-
fi n anqle between
preciable effect on the factor F'.
fixed anvils,
j fl
For 72" and 108O settings, the limit is determined by the fact
j anri '20
120 60
that for 19 undulations the factor F cannot be determined.
77 and 108" 60 ' I 30'
Factors F for three-point measurement, symmetrical settincj,
are giveri in table 8.
?he corrert~d value of the departure from roundness <1 IS
qive? bv the eqiiation
NOTE ~ When usinq tables 5 to 8
other combinations of çettinq
besides those given !ri tables 2 to 4 can he made
'j
il-
F.
where
1 15 the measured departure from roundness - it is the
6 Measuring conditions and instrument
largest value obtained from the preceding two or three corn-
binatiow of angles received in the required measurements
6.1 Measuring anvil static force
F IS rhe correction facror - it has a value extracted from
tables 2 to 8 las a first approximation, F- may be given a
The static measuring force should not exceed 1 N. The force
value of 2)
should, preferably. be adjustable and set at the lowest value
that will ensure cmtinuous contact between anvil and the sur-
Wher: measuring workpieces with a known even or odd
face being measured
number of undulations, the three-point measurement with
symmetrical setting at 60° angles between fixed anvils may be
For thin-walled workpieces, a high measuring force may affect
used according to table 8. This angle is usefui as it gives
the measuring result. Therefore it is necessary to reduce the
measured values of higher correction factors than the other
force to the minimum value possible.
angles in this International Standard. When using the 6ûo
angle, the measured value shall be corrected with the factor F'
given in table 8.
6.2 Measuring anvils
Depending on the form of the object, the measuring anvil shall
5 Evaluation of measurement errors
be selected from table 9, unless otherwise specified.
Tables 5 to 7 give true factors F- for any given number of
6.3 Fixed anvils
sinusoidal undulations and measuring method.
if the number of sinusoidal undulations ki known, the calcula- Point or line contact shall always be used. The following are
tion of the departure from roundness is made by using the F recommended :
factors directly from tables 5, 6, or 7 as indicated i
...

Norme internationale
INTERNATIONAL ORGANIZATION FOR STANDARDIZATION.ME)K~YHAPO~HAR OPrAHM3AlJMfl l-l0 CTAH~APTM3AL&lM~ORGANISATlON INTERNATIONALE DE NORMALISATION
M&hodes d ’baluation des &arts de circularit -
Mesurage par les m&hodes en deux et trois points
Measurement by two- and three-point methods
Methods for the assessment of departure from roundness -
Premihe hdition - 1985-07-15
Ref. no : IS0 42924985 (F)
CDU 531.717
ii
-
&at de surface, mesurage de circularit6, calcul d ’erreur.
Descripteurs : m&ologie,
Prix base sur 8 pages

---------------------- Page: 1 ----------------------
Avant-propos
L ’ISO (Organisation internationale de normalisation) est une federation mondiale
d ’organismes nationaux de normalisation (comites membres de I ’ISO). L ’elaboration
des Normes internationales est confide aux comites techniques de I ’ISO. Chaque
comite membre interesse par une etude a le droit de faire partie du comite technique
tree a cet effet. Les organisations internationales, gouvernementales et non gouverne-
mentales, en liaison avec I ’ISO, participent egalement aux travaux.
Les projets de Normes internationales adopt& par les comites techniques sont soumis
aux comites membres pour approbation, avant leur acceptation comme Normes inter-
nationales par le Conseil de I ’ISO. Les Normes internationales sont approuvees confor-
mement aux procedures de I ’ISO qui requierent I ’approbation de 75 % au moins des
comites membres votants.
La Norme internationale IS0 4292 a et6 elaboree par le comite technique ISO/TC 57,
M&ologie et propri&& des surfaces.
0 Organisation internationale de normalisation, 1985 0
imprim en Suisse

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IS0 4292-1985 (F)
NORME INTERNATIONALE
M6thodes d ’baluation des &arts de circularit -
Mesurage par les m&hodes en deux et trois points
1 Objet et domaine d ’application 31 mesurage en deux points: Mesurage entre deux tou-
ches coaxiales dont I ’une est fixe et I ’autre se deplace dans la
La presente Norme internationale specific des methodes d ’eva- direction du mesurage.
luation numerique de I ’ecart de circularite par une combinaison
de mesurages en deux et trois points: Voir figures 1 et 2.
a) determination par un mesurage en deux points (mesu-
mesurage en trois points: Mesurage entre trois tou-
32
rage des diametres) ;
ches dont deux sont fixes et la troisieme se deplace dans la
direction du mesurage.
b) determination par un mesurage en trois points, dit du
(( sommet )) (montage symetrique ou asymetrique) ;
Voir figures 3 a 8.
c) determination par un mesurage en trois points, dit du
(( cavalier )) (montage symetrique). 3.2.1 mbhode du <(sommet 1) : Mesurage en trois points
pour lequel les deux touches fixes sont situees d ’un c&e et la
Toute indication relative a I&art de circularite d ’une section est
touche de mesure de I ’autre tote de I ’axe de la piece, dans le
incomplete sauf mention du degre et de la nature des &arts. plan de mesurage.
Des methodes permettant cette description et une evaluation
correspondante sont specifiees dans I ’ISO 4291. Voir figures 3, 4, 6 et 7.
Les methodes specifiees dans I ’ISO 4291 sont peut-etre un peu
3.2.2 mbhode du ((cavalier)): Mesurage en trois points
trop precises pour les controles de routine ou en tours de fabri-
pour lequel les deux touches fixes sont situees du meme tote
cation. Les pieces a verifier peuvent aussi etre trop grandes
que la touche de mesure dans le plan de mesurage.
pour pouvoir etre mesurees de cette maniere.
Voir figures 5 et 8.
Les methodes specifiees ci-apres sont a la fois plus rapides et
moins coijteuses, pour evaluer les &arts de circularite. La
33 montage symetrique (mesurage en trois points) : Mon-
valeur evaluke s ’ecarte neanmoins de la valeur vraie. Les
tage pour lequel la direction de mesurage coi ’ncide avec la bis-
tableaux 2 a 8 permettent d ’estimer la difference entre la valeur
mesuree et la valeur vraie dans la mesure ou I ’on connaTt le sectrice de I ’angle forme par les touches fixes.
nombre d ’ondulations. de nature sinuso ’idale. Aucune theorie
Voir figures 3, 5, 6 et 8.
n ’existe encore pour estimer les &arts lorsque les ondulations
sont non sinusoi ’dales.
3.4 montage asymbtrique (mesurage en trois points) :
Montage pour lequel la direction de mesurage fait un angle
avec la bissectrice de I ’angle forme par les touches fixes.
2 Rhfkences
Voir figures 4 et 7.
IS0 4291, Mhhodes d ’e ’valuation des &arts de circularite’ -
Mesurage des variations du rayon.
I SO 6318, Mesurage de /a circularit& - Termes, de ’finitions et
4 Mesurage
param& tres de circularit
Pour tenir compte de tous les &arts de forme possibles et de
toutes les ondulations, un mesurage complet doit toujours
cornporter un mesurage en deux points et deux mesurages en
3 Dbfinitions trois points sous des angles differents de position des touches
fixes. La presente Norme internationale offre plusieurs varian-
Dans le cadre de la presente Norme internationale, outre les tes de choix des angles de position des touches fixes (voir
definitions don&es dans I ’ISO 6318, les definitions suivantes tableau 1). Dans certaines conditions prealables, les methodes
sont applicables. de mesurage peuvent etre amplifiees. Weir tableaux 2 a 4.1
1

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IS0 4292-1985 (F)
Tableau 1 - Angle de position des touches fixes en prenant la valeur maximale de A et les facteurs indiques
dans les tableaux 2, 3 ou 4.
~~~~
Montage sym&rique 1 Montage asymetrique
I
II existe une limite au nombre maximal d ’ondulations a prendre
Angle entre la
en compte pour choisir F, selon que ce nombre est connu et
direction de
Angle form6 par Angle form6 par mesurage et la
qu ’il est pair ou impair. Cette condition prealable est indiquee
les touches fixes, les touches fixes,
bissectrice de
dans les tableaux 2 a 4.
a a I ’angle form6 par
les touches fixes,
Pour les reglages a 90° et 120°, cette limite est de 22, ce qui
P
implique que, si le nombre d ’ondulations est superieur, cela
90° et 120° 120° 60°
n ’aura aucun effet notable sur le facteur F.
72O et 108’ 60° 3o"
Pour les reglages a 72O et 108O, la limite est determinee par le
fait qu ’a I9 ondulations, on ne peut pas determiner le fac-
La valeur corrigee de I ’ecart de circularite, 6, est don&e par
teur F.
I ’equation
Les facteurs F a utiliser pour les mesurages en trois points avec
A
a=-----
montage symetrique figurent dans le tableau 8.
F
NOTE - Si I ’on utilise les tableaux 5 3 8, on peut adopter d ’autres
Oil
combinaisons de montage que celles don&es dans les tableaux 2 B 4.
A est I ’ecart de circularite mesure, c ’est-a-dire la valeur la
plus elevee obtenue .avec les deux ou trois combinaisons
d ’angles precedentes ;
6 Conditions de mesurage et instruments de
F est un facteur de correction dont la valeur est extraite mesurage
des tableaux 2 a 8 (en premiere approximation, on peut
prendre F = 2).
6.1 Effort statique de la touche de mesure
Pour mesurer des pieces a nombre connu pair ou impair
L ’effort statique exerce par la touche de mesure ne doit pas
d ’ondulations, on peut suivre la methode de mesure en trois
depasser 1 N. II doit de preference etre reglable et fixe a la
points a montage symetrique et angle de 60° entre les touches
valeur la plus faible garantissant un contact continu entre la
fixes, conformement au tableau 8. Cet angle est utile dans la
touche et la surface mesuree.
mesure oti il donne les valeurs mesurees de facteurs de correc-
tion plus eleves que les autres angles de la presente Norme
Un effort de mesurage eleve peut affecter le resultat dans le cas
internationale. Si I ’on choisit I ’angle de 60°, la correction de la
de pieces minces. II est done necessaire de le reduire au mini-
valeur mesuree doit se faire a I ’aide du facteur F don& dans le
mum possible.
tableau 8.
6.2 Touches de mesure
5 baluation des erreurs de mesurage
Selon la forme de I ’objet et sauf specification contraire, la tou-
the de mesure est a choisir dans le tableau 9.
Les tableaux 5 a 7 donnent les facteurs F, mais correspondant a
n ’importe quel nombre donne d ’ondulations sinusoi ’dales et a
6.3 Touches fixes
n ’importe quelle methode de mesurage.
On doit toujours assurer un contact ponctuel ou lineaire en pri-
Si le nombre d ’ondulations sinusoidales est connu, le calcul de
vilegiant
I ’ecart de circularite se fait a I ’aide des facteurs F directement
extraits des tableaux 5, 6 ou 7 de la maniere indiquee dans les
- Pour les mesurages exterieurs: un support en V de
tableaux 2, 3 ou 4.
petit rayon. Le plan median de ce support doit se trouver
dans le meme plan que le plan de mesurage.
Si le nombre d ’ondulations sinusoi ’dales n ’est pas connu, il
- Pour les mesurages interieurs: une sphere de petit
n ’est pas possible de calculer exactement I ’ecart de circularite.
Dans ce cas, on peut calculer une valeur maximale, moyenne et rayon. Le plan median de la sphere doit se trouver dans le
meme plan que le plan de mesurage.
minimale de 6 a I ’aide de I ’equation don&e dans le chapitre 4
2

---------------------- Page: 4 ----------------------
IS0 4292-1985 (F)
Support r6glable
Support reglable
m /
Mesurage en deux points -
Figure 2 -
Support reglable
Figure 1 - Me
...