INTERNATIONAL IS0STANDARD 2768-2 First edition 1989-11-15 General tolerances - Part 2: Geometrical tolerances for features without individual tolerance indications Tolkrances g8ntGrales - Partie 2: Tolhances g6omhtriques pour Sments non affect& de tokrances individuelles --``,`,```,``,`,```,,,,``,`,```-`-`,,`,,`,`,,`--- Reference number IS0 2768-2 : 1959 (E) COPYRIGHT 2003; International Organization for Standardization Document provided by IHS Licensee=Deere & Co/9999663100, User=, 02/14/2003 00:03:32 MST Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584. `... Part I: Tolerances for linear and angular dimensions without individual tolerance indications . This first edition of IS0 2768-2.`. IS0 2768 consists of the following parts. 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.`.. in liaison with ISO.`. without permission in writing from the publisher. No part of this publication may be reproduced or utilized in any form or by any means. cancel and replace IS0 2759 : 1973.```-`-`. .```. User=. 02/14/2003 00:03:32 MST Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584. They are approved in accordance with IS0 procedures requiring at least 75 % approval by the member bodies voting.``. including photocopying and microfilm. International Organization for Standardization Document provided by IHS Licensee=Deere & Co/9999663100. 0 IS0 1999 All rights reserved. govern- mental and non-governmental. also take part in the work.`--- Foreword IS0 (the International Organization for Standardization) is a worldwide federation of national standards bodies (IS0 member bodies). Limits and fits.. under the general title Genera/ tolerances: . together with IS0 2758-1 : 1969.```.`. IS0 2768-2 : 1989 (EI --``. IS0 collaborates closely with the International Electrotechnical Commission (IECI on all matters of electrotechnical standardization. International Standard IS0 2768-2 was prepared by Technical Committee ISO/TC 3.. 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 Organization for Standardization Case postale 56 l CH-1211 Geneve 20 l Switzerland Printed in Switzerland ii COPYRIGHT 2003. International organizations.``. The work of preparing International Standards is normally carried out through IS0 technical committees.. Fart 2: Geometrical tolerances for features without individual tolerance indi- cations Annexes A and B of this part of IS0 2768 are for information only. electronic or mechanical.`. . 02/14/2003 iii 00:03:32 MST Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584. IS0 2768-2 : 1989 (El Introduction All features on component parts always have a size and a geometrical shape. .``.`.`.```-`-`. User=..```. i. The use of general tolerances for size and geometry simplifies the task of ensuring that this prerequisite is met.``. when exceeded.`. nothing shall be implied or left to judge- ment in the workshop or in the inspection department. For the deviation of size and for the deviations of the geometrical characteristics (form.`...`.`--- COPYRIGHT 2003. International Organization for Standardization Document provided by IHS Licensee=Deere & Co/9999663100. orientation and location) the function of the part requires limitations which.`..```.e.. --``. impair this function. The tolerancing on the drawing should be complete to ensure that the elements of size and geometry of all features are controlled. on the length of the cor- responding line and.. the editions indicated were valid. General tolerances . cations. 5 General geometrical tolerances ance characteristics. linear and angular dimensions without individual tolerance indi- ances specified in this part of IS0 2768.2)... Technical drawings .```.1. through lateral length of the surface. such tolerances should be indicated directly in accordance with IS0 1101 (see clause A. Datums and datum-systems for geometrical tolerances. --``. positional toler- ances and total run-out. coaxiality. 02/14/2003 1 00:03:32 MST Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584.. angularity. the respective customary workshop accuracy has to be taken into consideration.`. User=. symbols. International Organization for Standardization Document provided by IHS Licensee=Deere & Co/9999663100. Technical drawings . Fundamental toleranc- smaller geometrical tolerances are required or larger ing principle. 5. the definitions for refer to this part of IS0 2768 in accordance with clause 6.. or the diameter of the circular sur- reference in this text. All standards are subject to revision. It specifies general geometrical tolerances in maintain registers of currently valid International Standards.Part 7: Tolerances for workshop accuracy lies within the general geometrical toler. constitute provisions of this part of face.`. INTERNATIONAL STANDARD IS0 2758-2 : 1989 (E) General tolerances - Part 2: Geometrical tolerances for features without individual tolerance indications 1 Scope IS0 2768. They geometrical tolerances given in IS0 1101 and IS0 5459 apply. 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.```-`-`.```. excluding cylindricity.1 Straightness and flatness tolerancing principle in accordance with IS0 8015 is used and indicated on the drawing (see clause 6. profile of any line. 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.``. When selecting the tolerance class. (see also clause 5. When a tolerance is selected from table 1. definitions.Tolerancing of form.`--- three tolerance classes.`. special examination is required to ascertain whether the customary IS0 2768-l : 1989.`. COPYRIGHT 2003.1) profile of any surface.``.. IS0 5459 : 1981.`. IS0 1101 : 1983. Technical drawings . . apply to features which do not have respective individual geometrical tolerance indications. geometrical tolerances are permissible and more economical for any individual feature. Its application to features Generalities.Geometrical toleranc- 2 General ing . however. General geometrical tolerances apply to all geometrical toler. At the time of publication. and parties to This part of IS0 2768 is intended to simplify drawing indica.Geometrical toleranc- This part of IS0 2768 mainly applies to features which are pro. manufactured by other processes is possible. it shall be 3 Normative references based. ing . general geometrical tolerances in accordance with this part of IS0 2768 should be used when the fundamental 5. in the case of flatness. location and run-out - duced by removal of material. If IS0 8015 : 1995. The general tolerances on straightness and flatness are given in table 1. in the case of straightness.11. indications on drawings. on the longer The following standards contain provisions which. orientation. Members of IEC and IS0 dividual indication.1 Tolerances for single features In any event. g.2 Parallelism since the deviation in radial run-out comprises the deviation in coaxial- ity and the deviation in circularity.`.5 Coaxiality The tolerances specified in 5. straightness deviation and parallelism deviation of opposite See examples in clause B. NOTE .2. General tolerances on straightness 5. The general tolerances on symmetry are given in table 3.2.2 Tolerances for related features 5. generator lines.5 K 033 ‘323 1 L W-3 1 1 I.The deviation in coaxiality may. surface of revolution) are given in table 4. either may be taken as the datum (see clause B. Each of these components is controlled by its in- dividually indicated or its general tolerance.2.2.3 0. or . 5.4 Symmetry given in table 4 (see examples in clause 8.6 Circular run-out ance. if the features are of equal nominal The general tolerances on circular run-out (radial..``. IS0 2768-2 : 1989 (El Table 1 .`.2.2. of nominal lengths Toler.. f The cylindricity deviation comprises three components : circularity deviation.`.```. for functional reasons.2).3 Perpendicularity and flatness The general tolerances on perpendicularity are given in table 2.2 Circularity K O. 2 COPYRIGHT 2003.`. General tolerances on perpendicularity Values in millimetres Perpendicularity tolerances for ranges of K nominal lengths of the shorter side I ante class I over 100 I over 300 over 1 000 up to loo up to 300 up to 1 oao up to 3 ooo I H 02 0. Symmetry tolerances for ranges of ance in accordance with IS0 1101 should be indicated for the feature Toler. axial and any length.4 0. The longer of the two features shall be taken as the datum.5 5.`--- Straightness and flatness tolerances for ranges taken as the datum. General tolerances on cylindricity are not specified. either may be taken as the datum.`.4 ‘A6 033 1 L W-3 1 I. General tolerances on coaxiality are not specified. at least one of the two features has a median plane. if the sides are of equal nominal length. ante class over 100 over 300 over 1 Do0 up to 100 Sometimes. the cylindricity deviation has to be smaller Values in millimetres than the combined effect (see clause B-3) of the general tolerances on circularity.The general tolerances on symmetry apply where NOTES .4). the axes of the two features are perpendicular to each other..5 2 5. The longer of the two features shall be taken as the datum. The general tolerance on parallelism is equal to the numerical value of the size tolerance or the flatness/straightness toler. nominal lengths concerned. but in no case shall it be greater than the respective tolerance value for circular radial run-out 5.... either may be taken as the datum. H 0.2 to 5. an individual cylindricity toler.5 2 The general tolerance on circularity is equal to the numerical value of the diameter tolerance. General tolerances on symmetry 2 If. straightness and parallelism. be as great as the tolerance value for circular radial run-out given in table 4. in the case of a fit.```-`-`. Values in millimetres The longer of the two sides forming the right angle shall be --``.2.```. in an extreme case. e. 02/14/2003 00:03:32 MST Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584. if the 5. User=.3 Cylindricity features are of equal nominal length. 5.1 General 5. whichever is the greater.`.6 apply to all features which are in relation to one another and which have no respec. ance class Table 2 . .2. NOTE . tive individual indication.1.5. the indication of the envelope I up to 300 I up to 1 ooo up to 3 ooo requirement @ is appropriate. International Organization for Standardization Document provided by IHS Licensee=Deere & Co/9999663100.``.1. Table 3 . e.5 I 6. individually indicated straightness tolerances which are greater than their size tolerances. the following information shall IS0 2768-mK-E be indicated in or near the title block: NOTE . Otherwise. a single feature of size comprises a cylindrical surface or two parallel plane surfaces. 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. for circular radial run-out. nominal length.``.``.`. the longer of the two which are implied but not indicated.2 I IS0 2768-K I L I 0. because this part of features shall be taken as the datum.1 : 6. 6. 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 2768-mk paired (see clause A. if the features are of equal IS0 2766 specifies general tolerances on perpendicularity. c) the tolerance class in accordance with this part of 7 Rejection IS0 2766. the designation “E” shall 6 Indications on drawings be added to the general designation specified in 6. International Organization for Standardization Document provided by IHS Licensee=Deere & Co/9999663100. User=.4).```..`.```-`-`.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 2766-1. IS0 2766-2 : 1989 (E) For general tolerances on circular run-out..2 If the general dimensional tolerances (tolerance class m) Table 4 . cordance with IS0 2766-l do not apply to right angles (W’).The envelope requirement @ cannot apply to features with a) “IS0 2768”.`.3 In cases where the envelope requirement @ also applies to all single features of size l). either may be taken as the datum.`. 1) For the purposes of this part of IS0 2768.g. ...`--- COPYRIGHT 2003. Unless otherwise stated. stock material.`. General tolerances on circular run-out shall not apply. --``.. 02/14/2003 3 00:03:32 MST Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584.```. the respective letter shall be omitted from the Values in millimetres designation to be indicated on the drawing : Tolerance class Circular run-out tolerances EXAMPLE H I or1 I K I 0.`. b) the tolerance class in accordance with IS0 2766-l .. l mm for curacy” is known before the contract is placed. only if the function is impaired. . This type of tolerance equal to or greater than its customary workshop accuracy. dicated in the drawing. For duction planning and will assist quality control services in example.`. for the most part. 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.```-`-`.```.g.1 General tolerances should be indicated on the drawing b) the design draughtsman saves time by avoiding detailed by reference to this part of IS0 2766 in accordance with tolerance calculations as it is sufficient only to know that the clause 6. check by sampling that its customary workshop ac- tolerancing. International Organization for Standardization Document provided by IHS Licensee=Deere & Co/9999663100. not following advantages : always impaired when the general tolerance is (occasionally) exceeded at any feature of the workpiece. IS0 2768-2 : 1989 (El Annex A (informative) Concepts behind general tolerancing of geometrical characteristics A.e. d) those features remaining. and the tainties and misunderstandings is no longer necessary with the larger tolerance will provide a gain in manufacturing economy.`. will.`--- general tolerance.4 The tolerance the function allows is often greater than A. The general geo- In these special cases. 0. but should be stated . and 0.3 Using general geometrical tolerances leads to the the general tolerance. concept of general geometrical tolerances. These advantages are fully obtained only when there is suffi- cient reliability that the general tolerances will not be exceeded.`. if. the larger geometrical tolerance should metrical tolerances define the required accuracy of “good be indicated individually adjacent to the particular feature. workshop machinery and the usual workmanship nor. workmanship”.l mm diameter by 66 mm their analysis of inspection requirements.``. User=. Specifying tolerances would be of no benefit in this particular workshop. this also straightness of surface elements.this will be helpful for pro- mally do not manufacture features with greater deviations. 02/14/2003 00:03:32 MST Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584. curacy does not deteriorate.```. e. allows full use of the concept of general geometrical . the circularity tolerance of a large and thin ring. find out by measurements what its customary work- In cases where the function of a feature allows a geometrical shop accuracy is .l mm for circularity. which have individually in- A. tolerance equal to or larger than the general tolerance values. The workshop should. 4 COPYRIGHT 2003. In any relatively small tolerances and which therefore may cause event. The values of general tolerances correspond to grades of cl the drawing readily indicates which features can be pro- customary workshop accuracy.`. which corresponds to dicated geometrical tolerances. quality engineering by reducing inspection levels.. for functional reasons. a feature of 25 mm I!I 0. function allows a tolerance greater than or equal to the --``. a feature requires a smaller i. A.. special effort in the production . be the customary workshop accuracy. which also assists being selected and indicated on the drawing. accept only those drawings having general tolerances on the drawing as described in clause 6.l 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. This type of tolerance falls out- side the scope of general tolerances. long manufactured in a workshop with a customary accuracy e) purchase and sub-contract supply engineers can nego- equal to or finer than IS0 276%mH contains the geometrical tiate orders more readily since the “customary workshop ac- deviations well within 0. the appropriate tolerance class duced by normal process capability. this should not be individually indicated. therefore. IS0 2766). then that feature workshop is equal to or finer than the general tolerances in- should have the smaller tolerance indicated individually adja. However.``..2 Above a certain tolerance value..`. there is usually no gain in those controlling features for which the function requires manufacturing economy by enlarging the tolerance. The function of the part is. since in this respect the drawing is complete. when the customary workshop accuracy of the particular tolerance value than the “general tolerances”.`. cent to the particular feature.. therefore.. . 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. l . According to the principle of independency (see IS0 8015).``..`. Principle of independency..`.`--.l).`. LMaximum limit of size Figure B. If the envelope requirement @ is individually indicated adjac- general geometrical tolerances apply independently of the ent to the feature or generally to all features of size as described actual local size of the workpiece features..```. 02/14/2003 5 00:03:32 MST Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584. IS0 2768-2 : 1989 (E) Annex B (informative) Further information B. International Organization for Standardization Document provided by IHS Licensee=Deere & Co/9999663100..-Maximum limit of size -Maximum Maximum circularity deviation (resulting from a lobed form) Maximum straightness deviation deviation-.. Accordingly. . maximum permissible deviations on the same feature COPYRIGHT 2003.`..```-`-`. --``.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. User=.`..``.```. the in clause 6. Dimensions in millimetres t Tolerancing IS0 8015 y General tolerances IS0 2768-mH I 250 -I . this requirement should also be complied with.`. Examples B.```-`-`.`. EXAMPLE 2 (see figure 8. the sum of the three tolerances can be taken into account..4 mm which is greater than the value of parallelism deviation is limited by the numerical value of the size 0. IS0 2768-2 : 1989 (E) B. Parallelism deviation equal to the numerical Figure B.``.2) The combined effect of the general tolerances of circularity. International Organization for Standardization Document provided by IHS Licensee=Deere & Co/9999663100. the general tolerance on circularity is equal to simplicity.``.3 . 02/14/2003 00:03:32 MST Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584. The permissible deviations for the diameter of 25 mm are +0.```. Values in millimetres Example Indication on the drawing Circularity tolerance zone 1 IS0 2768-K 2 IS0 276%mK Figure B.2 mm. therefore. the numerical value of 0.`.. These deviations lead to the Depending on the shapes of the deviations of the features.```. straightness and parallelism is. for geometrical reasons.2) IS0 275B-mK apply.`.2. the value of 0.`..1.2) .21 The general tolerances in accordance with the indication B. in order to decide whether the envelope requirement the numerical value of the diameter tolerance.`. Examples of general tolerances on circularity --``. . smaller than the sum of the three tolerances since there is also a certain The permissible deviation of the diameter is indicated directly limitation by the size tolerance. straightness or flatness tolerance (see figure B.`. 0 E or an individual cylindricity tolerance is to be indicated.2 Circularity (see 5.2 mm given in table 4.3 Cylindricity (see note 2 in 5.`--- Dimensional tolerance -Straightness tolerance Figure B..2 .4 Parallelism (see 5. for the sake of on the drawing.4).3) EXAMPLE 1 (see figure 8.. User=. However.2 mm.Parallebsm deviation equal to the numerical value of the size tolerance value of the straightness tolerance COPYRIGHT 2003. tolerance (see figure B.4 .1..3) or by the numerical value of the applies for the circularity tolerance. ```-`-`.`.4) .`. IS0 2758-2 : 1989 (E) 8.I --``.```.``.`--- b) Datum : longer feature (I..) I I i .`. 02/14/2003 00:03:32 MST Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584.I it’-‘-l g& I u ‘1 -I 12 d) Datum : longer feature (I.5 .`.``..2. International Organization for Standardization Document provided by IHS Licensee=Deere & Co/9999663100.2. User=. . 1 fi c) Datum : longer feature (/.4) COPYRIGHT 2003..`..5 Symmetry (see 5.`.. Examples of general tolerances on symmetry (datums specified in accordance with 5..) Figure 8. Examples a) Datum : longer feature (/.```. `. Figure B.`...`.```-`-`. 2 As some tolerances also limit the deviations of other characteristics of the same feature. geometrical tolerances. not all general tolerances are shown in the interpretation above.```.`... 02/14/2003 00:03:32 MST Questions or comments about this message: please call the Document Policy Management Group at 1-800-451-1584.`.``.`--- 8 COPYRIGHT 2003.```.`.. User=.6 ..6 Example of a drawing Indication on the drawing Dimensions in millimetres LSa. machining tolerances. IS0 2768-2:1989 (EI B. 245" 83H12(+$') Tolerancing IS0 8015 Interpretation General tolerances IS0 2768-mH t - NOTES 1 The tolerances shown in chain thin double-dashed lines (boxes and circles) are general tolerances.``. e. These tolerance values would be automatically achieved by machining in a workshop with a customary accuracy equal to or finer than IS0 2768-mH and would not normally require to be inspected.4 Descriptors : fundamental tolerances. Price based on 8 pages --``. the perpendicularity tolerance also limits the straightness deviations.g. . International Organization for Standardization Document provided by IHS Licensee=Deere & Co/9999663100.. Example of general tolerances on a drawing UDC 621.1 : 744.753.