Table Of Contentइंटरनेट मानक
Disclosure to Promote the Right To Information
Whereas the Parliament of India has set out to provide a practical regime of right to
information for citizens to secure access to information under the control of public authorities,
in order to promote transparency and accountability in the working of every public authority,
and whereas the attached publication of the Bureau of Indian Standards is of particular interest
to the public, particularly disadvantaged communities and those engaged in the pursuit of
education and knowledge, the attached public safety standard is made available to promote the
timely dissemination of this information in an accurate manner to the public.
“जान1 का अ+धकार, जी1 का अ+धकार” “प0रा1 को छोड न’ 5 तरफ”
Mazdoor Kisan Shakti Sangathan Jawaharlal Nehru
“The Right to Information, The Right to Live” “Step Out From the Old to the New”
IS 2102-2 (1993): General tolerances, Part 2: Geometrical
tolerances for features without individual tolerance
indications [PGD 20: Engineering Standards]
“!ान $ एक न’ भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
““IInnvveenntt aa NNeeww IInnddiiaa UUssiinngg KKnnoowwlleeddggee””
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता हहहहै””ै”
Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”
IS 2102 ( Part 2 ) : 1993
IS0 2768-2 : 1989
FrFlm-d
0
TPV 2 g?;rW$Wti F i!+d i+
fqqT WT!@firdfm "f= itfim"rSI $
indian Standard
GENERAL TOLERANCES
PART 2 GEOMETRICAL TOLERANCES FOR FEATURES WITHOUT INDIVIDUAL
TOLERANCE INDICATIONS
(Second Reprint AUGUST 1998 )
UDC 621’753’1 : 744’4
@ BIS 1993
BUREAU OF INDIAN STANDARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002
March 1993 Price Group 4
gnireenignE sdradnatS lanoitceS Committee, ML 10
LANOITAN FOREWORD
sihT naidnl dradnatS ( traP % ) hcihw si lacitnedi htiw 0SI Z-8672 : 9891 lareneG‘ secnarelot -
traP 2 : lacirtemoeG secnarelot rof serutaef tuohtiw laudividni ecnarelot saw’snoitacidni detpoda
yb eht uaeruB fo naidnI sdradnatS no eht snoitadnemmocer fo eht gnireenignE sdradnatS
lanoitceS Committee ( ML 10 ) dna lavorppa fo eht thgiL lacinahceM gnireenignE noisiviD
.licnuoC
lareneG lacirtemoeg secnarelot ylppa ot lla lacirtemoeg ecnarelot scitsiretcarahc gnidulcxe
,yticrednilyc eliforp fo yna ,enil eliforp fo yna ,ecafrus ,ytiralugna ,ytilaixa-oc lanoitisop
secnarelot dna latot .nur ehT dradnats seificeps lareneg lacirtemoeg secnarelot rof eerht
ecnarelot .sessalc sihT dradnats si osla dednetni ot yfilpmis gniward .noitacidni
nI eht detpoda dradnats niatrec ygolonimret dna snoitnevnoc era ton lacitnedi htiw esoht desu
ni eht naidnI ,dradnatS noitnetta si yllaicepse nward ot eht :gniwollof
a) Comma ( , ) sah neeb desu sa a lamiced marker elihw ni naidnI ,sdradnatS eht tnerruc
ecitcarp si ot esu tniop ( . ) sa eht lamiced marker.
b) Wherever eht sdrow lanoitanretnI‘ ’dradnatS ,raeppa gnirrefer ot siht ,dradnats yeht
llahs eb daer sa naidnI‘ .’dradnatS
nI eht detpoda dradnats ecnerefer sraeppa ot niatrec lanoitanretni sdradnats rof hcihw naidnI
sdradnatS osla .stsixe ehT gnidnopserroc naidnI sdradnatS hcihw era ot eb detutitsbus ni
rieht ecalp era detsil woleb gnola htiw rieht eerged fo ecnelaviuqe rof eht snoitido :detacidni
International Corresponding Indian Standard Degree of
Standard equivalence
0SI 3891-1011 SI 8000 ( traP 1 ) : 5891 lacirtemoeG ecnarelot lacitnedI
no lacinhcet sgniward : traP 1 secnareloT fo
form ,noitatneiro noitacol dna tuo-nur dna
etairporppa lacirtemoeg snoitinifed ( first
revision )
0SI 2768-l : 9891 SI 2012 ( traP 1 ) : 3991 lareneG secnarelot : lacitnedI
traP 1 secnareloT rof raenil dna ralugna
snoisnemid tuohtiw laudividni ecnarelot
snoitacidni ( third revision )
0SI 9545 : 1891 SI 12701 : 3891 mutaD dna mutad systems rof lacitnedI
lacirtemoeg gnicnarelot no lacinhcet sgniward
0SI 5108 : 5891 SI 06121 : 7891 lacinhceT sgniward - -adnuF lacitnedI
latnem gnicnarelot selpicnirp
IS 2102 ( Part2) : +993
ISo 2766-2 : 1969
Indian Standard
GENERAL TOLERANCES
PART 2 GEOMETRICAL TOLERANCES FOR FEATURES WITHOUT INDIVIDUAL
TOLERANCE INDICATIONS
1 Scope IS0 2768. At the time of publication, the editions indicated
were valid. All standards are subject to revision, and parties to
This part of IS0 2768 is intended to simplify drawing indica- agreements based on this part of IS0 2768 are encouraged to
tions and specifies general geometrical tolerances to control investigate the possibility of applying the most recent editions
those features on the drawing which have no respective in- of the standards indicated below. Members of !EC and IS0
dividual indication. It specifies general geometrical tolerances in maintain registers of currently valid International Standards.
three tolerance classes.
IS0 1101 : 1983, Technical drakngs - Geometrical toleranc-
This part of IS0 2768 mainly applies to features which are pro- ing - Toleranciny of form, orientation, location and run-out -
duced by removal of material. Its application to features Generalities, definitions, symbols,, indications on drawings.
manufactured by other processes is possible; however, special
examination is required to ascertain whether the customary :
IS0 2768-l 1989, General tolerances - Part 1: Tolerances for
workshop accuracy lies within the general geometrical toler-
linear and angular dimensions without individual tolerance indi-
antes specified in this part of IS0 2768.
cations.
IS0 5459 : 1981, Technical drawings - Geometrical toleranc-
2 General
ing - Datums and datum-systems for geometrical tolerances.
When selecting the tolerance class, the respective customary
:
workshop accuracy has to be taken into consideration. If IS0 8015 1985, Technical drawings - Fundamental toleranc-
smaller geometrical tolerances are required or larger ing principle.
geometrical tolerances are permissible and mo re economical for
any individual feature, such tolerances should be indicated
directly in accordance with IS0 1101 (see clause A.2).
4 Definitions
General geometrical tolerances in accordance with this part of.
IS0 2768 apply when drawings or associated specifications For the purposes of this part of IS0 2768, the definitions for
refer to this part of IS0 2768 in accordance with clause 6. They geometrical tolerances given in IS0 1101 and IS0 5459 apply.
apply to features which do not have respective individual
geometrical tolerance indications.
General geometrical tolerances apply to all geometrical toler-
5 General geometrical tolerances
ante characteristics, excluding cylindricity, profile of any line,
(see also clause B. 1)
profile of any surface, angularis coiaxiality, positional toler-
antes and total run-out.
5.1 Tolerances for single features
In any event, general geometrical tolerances in accordance with
this part of IS0 2768 should be used when the fundamental
5.1.1 Straightness and flatness
tolerancing principle in accordance with IS0 8015 is used and
indicated on the drawing (see clause B.l).
The general tolerances on straightness and flatness are given in
table 1. When a tolerance is selected from table 1, it shall be
3 Normative references based, in the case of straightness, on the length of the cor-
responding line and, in the case of flatness, on the longer
The following standards contain provisions which, through lateral length of the surface, or the diameter of the circular sur-
reference in this text, constitute provisions of this part of face.
1
IS 2102 ( Part2) : 1993
IS0 2769-2 : 1999
Table 1 - General tolerances on straightness 5.2.3 Perpendicularity
and flatness
The general tolerances on perpendicularity are given in table 2.
Values in millimetres
The longer of the two sides forming the right angle shall be
~TStraighutness a~nd flatne~ss toler~ances f~or range~s ~take~n as th~e datumn; if the ~sides a~re of eq~ual nom~inal len~gth, !~~
either may be taken as the datum.
Table 2 - General tolerances on perpendicularity
Values in millimetres
l-i 0.02 0.05 0.1 0.2 O,3 0.4
Perpendicularity tolerances for ranges of
K 0.05 0.1 0.2 O,4 0.6 0,B Toler- nominal lengths of the shorter side
L 0.1 0.2 0.4 0.8 1.2 1.6 ante
class over 100 over 300 over 1 WO
up to loo
up to 300 up to 1 IlcCl up to 3 ooo
iI 20 0.3 0.4 0.5
5.1.2 Circularity K 0.4 0.6 0.8 1
L O-6 1 1.5 2
The general tolerance on circularity is equal to the numerical
value of the diameter tolerance, but in no case shall it be greater
than the respective tolerance value for circular radial run-out
5.2.4 Symmetry
given in table 4 (see examples in clause 8.2).
The general tolerances on symmetry are given in table 3. The
longer of the two features shall be taken as the datum; if the
5.1.3 Cylindricity features are of equal nominal length, either may be taken as the
datum.
General tolerances on cylindricity are not specified.
NOTE - The general tolerances on symmetry apply where
NOTES - at least one of the two features has a median plane, or
: - the axes of the two features are perpendicular to each other.
1 The cylindricity deviation comprises three components circularity
deviation, straightness deviation and parallelism deviation of opposite See examples in clause 8.5
generator lines. Each of these components is controlled by its in-
dividually indicated or its general tolerance.
Table 3 - General tolerances on symmetry
2 If, for functional reasons, the cylindricity deviation has to be smaller Values in millimetres
than the combined effect (see clause 8.31 of the general tolerances on
circularity, straightness and parallelism, a n individual cvlindricity toler- Symmetry tolerances for ranges of
ance in accordance with IS0 1101 should be indicated for the feature Toler- nominal lengths
concerned. ante
class over 100 over 300 I over 1 WO
up to loo
up to 3cm up to 1 ooo upto
Sometimes, e.g. in the case of a fit, the indication of the envelope
requirement @ is appropriate. H 0.5
K 0.6 0.8 1
L 0.6 1 I,5 2
5.2 Tolerances for related features
5.2.1 General
5.2.5 Coaxiality
The tolerances specified in 5.2.2 to 5.2.6 apply to all features
which are in relation to one another and which have no respec- General tolerances on coaxiality are not specified.
tive individual indication.
NOTE - The deviation in coaxiality may, in an extreme case, be as
great as the tolerance value for circular radial run-out given in table 4.
5.2.2 Parallelism since the deviation in radial run-out comprises the deviation in coaxial-
ity and the deviation in circularity.
The general tolerance on parallelism is equal to the numerical’
value of the size tolerance or the flatness/straightness toler- 5.2.6 Circular run-out
ance, whichever is the greater. The longer of the two features
shall be taken as the datum; if the features are of equal nominal The general tolerances on circular run-out (radial, axial and any
length, either may be taken as the datum (see clause 8.4). surface of revolution) are given in table 4.
2.
IS 2102 ( Part2) : 1993
IS0 2766-2 : 1969
For general tolerances on circular run-out, the bearing surfaces In this case the general tolerances for angular dimensions in ac-
shall be taken as the datum if they are designated as such. cordance with IS0 2766-l do not apply to right angles W’),
Otherwise, for circular radial run-out, the longer of the two which are implied but not indicated, because this part of
features&all be taken as the datum; if the features are of equal IS0 2768 specifies general tolerances on perpendicularity.
nominal length, either may be taken as the datum.
6.2 If the general dimensional tolerances (tolerance class m)
Table 4 - General tolerances on circular run-out
shall not apply, the respective letter shall be omitted from the
:
Values in millimetres designation to be indicated on the drawing
1 Tolerance class 1 Circular run-out tolerances 1
EXAMPLE
I
IS0 2766-K
I
L I 0.5 I
6.3 In cases where the envelope requirement @ also
applies to all single features of size”, the designation “E” shall
6 Indications on drawings be added to the general designation specified in 6.1:
6.1 If general tolerances in accordance with this part of EXAMPLE
IS0 2766 shall apply in conjunction with the general tolerances
in accordance with IS0 27661, the following information shall IS0 2768-mK-E
be indicated in or near the title block:
NOTE - The envelope requirement @ cannot apply to features with
a) “IS0 2766’; individually indicated straightness tolerances which are greater than
their size tolerances, e.g. stock material.
;
b) the tolerance class in accordance with IS0 2766-l
lc
the tolerance class in accordance with this part of 7 Rejection
IS0 2766.
Unless otherwise stated, workpieces exceeding the general
EXAMPLE geometrical tolerance shall not lead to automatic rejection pro-
vided that the ability of the workpiece to function is not im-
IS0 2766-mk paired (see clause A.4).
1) For the purposes of this part of IS0 2768, a single feature of size comprises a cylindrical surface or two parallel plane surfaces
3
I$ 2102 ( Part 2) : 1993
IS0 2766-2 : 1969
Annex A
(informative)
Concepts behind general tolerancing of geometrical characteristics
A.1 General tolerances should be indicated on the drawing b) the design draughtsman saves time by avoiding detailed
by reference to this part of IS@ 2766 in accordance with tolerance calculations as it is sufficient only to know that the
clause 6. function allows a tolerance greater than or equal to the
;
general tolerance
The values of general tolerances correspond to grades of lc
the drawing readily indicates which features can be pro-
customary workshop accuracy, the appropriate tolerance class
duced by normal process capability, which also assists
being selected and indicated on the drawing.
quality engineering by reducing inspection levels;
d) those features remaining, which have individually in-
A.2 Above a certain tolerance value, which corresponds to dicated geometrical tolerances, will, for the most part, be
the customary workshop accuracy, there is usually no gain in those controlling features for which the function requires
manufacturing economy by enlarging the tolerance. In any relatively small tolerances and which therefore may cause
event, workshop machinery and the usual workmanship nor- special effort in the production - this will be helpful for pro-
mally do not manufacture features with greater deviations. For duction planning and will assist quality control services in
example, a feature of 26 mm f 0,l mm diameter by 60 mm their analysis of inspection requirements ;
long manufactured in a workshop with a customary accuracy
e) purchase and sub-contract supply engineers can nego-
equal to or finer than IS0 2766mH contains the geometrical
tiate orders more readily since the “customary workshop ac-
deviations well within 0,l mm for circularity, 0,l mm for
curacy” is known before the contract is placed; this also
straightness of surface elements, and 0.1 mm for circular radial
avoids arguments on delivery between the buyer and the
run-out (the values given have been taken from this part of
supplier, since in this respect the drawing is complete.
IS0 2766). Specifying tolerances would be of no benefit in this
particular workshop. These advantages are fully obtained only when there is suffi-
cient reliabilitv that the general tolerances will not be exceeded,
However, if, for functional reasons, a feature requires a smaller i.e. when the customary workshop accuracy of the particular
tolerance value than the “general tolerances”, then that feature workshop is equal to or finer than the general tolerances in-
should have the smaller tolerance indicated individually adja- dicated in the drawing.
cent to the particular feature. This type of tolerance falls out-
side the scope of general tolerances. The workshop should, therefore,
- find out by measurements what its customary work-
In cases where the function of a featur e allows a geometrical shop accuracy is ;
tolerance equal to or larger than the general tolerance values,
this should not be individually indicated, b ut should be stated - accept only those drawings having general tolerances
on the drawing as described in clause 6. This type of tolerance equal to or greater than its customary workshop accuracy;
allows full use of the concept of general geometrical
- check by sampling that its customary workshop ac-
tolerancing.
curacy does not deteriorate.
There will be “exceptions to the rule” where the function
Relying on undefined “good workmanship” with all its uncer-
allows a larger tolerance than the general tolerances, and the tainties and misunderstandings is no longer necessary with the
larger tolerance will provide a gain in manufacturing economy. concept of general geometrical tolerances. The general geo-
In these special cases, the larger geometrical tolerance should metrical tolerances define the required accuracy of “good
be indicated individually adjacent to the particular feature, e.g. workmanship”.
the circularity tolerance of a large and thin ring.
A.4 The tolerance the function allows is often greater than
A.3 Using general geometrical tolerances leads to the the general tolerance. The function of the part is, therefore, not
:
following advantages always impaired when the general tolerance is (occasionally)
exceeded at any feature of the workpiece. Exceeding the
a) drawings are easier to read and thus communication is general tolerance should lead to a rejection of the workpiece
;
made more effective to the user of the drawing only if the function is impaired.
4
IS 2102 ( Part 2) : 1993
IS0 2766-2 : 1969
Annex B
(informative)
Further information
B.l General geometrical tolerances general geometrical tolerances may be used even if the features
(see clause 5) are everywhere at their maximum material size (see figure B.l).
According to the principle of independency (see IS0 8015). If the envelope requirement @ is individually indicated adjac-
general geometrical tolerances apply independently of the ent to the feature or generally to ail features of size as described
actual local size of the workpiece features. Accordingly, the in clause 6, this requirement should also be complied with.
Dimensions in millimetres
,,-Maximum limit of size
Maximum circularity deviation
(resulting from a lobed form)
Maximum straightness deviation
cv
d
Maximum limit of size
;
Figure B.l - Principle of independency maximum permissible deviations on the same feature
5
