IS 14962-1: ISO General Purpose Metric Screw Threads - Tolerances, Part 1: Principle and Basic Data

25 Pages·2001·1.6 MB·English

by  Bureau of Indian Standards

इंटरनेट 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 14962-1 (2001): ISO General Purpose Metric Screw Threads
- Tolerances, Part 1: Principle and Basic Data [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 14962 (Part 1) :2001
ISO 965-1:1998

ISO GENERAL PURPOSE METRIC SCREW
THREADS — TOLERANCES
PART 1 PRINCIPLES AND BASIC DATA
ICS 21.040.10

0 BIS 2001
BUREAU OF IN DIANSTA ND ARDS
MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002
December 2001 Price Group 8
Engineering Standards Sectional Committee, BP 20
NATIONAL FOREWORD
This Indian Standard (Part 1) which is identical with ISO 965-1 : 1998 ‘ISO general purpose metric
screw threads — Tolerances — Part 1: Principles and basic data’ issued by the International
Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the
recommendation of the Engineering Standards Sectional Committee and approval of the Basic and
Production Engineering Division Council.
This Committee, responsible for the preparation of Indian Standards on Screw Threads, decided to
revise all the six Parts of IS 4218 in the following manner:
a) The revised IS 4218 to be published in four parts that is (Parts 1 to 4) by adopting ISO 68-1 :
1998, ISO 261 : 1998, ISO 724: 1993 and ISO 262: 1998 respectively covering the various
requirements of ISO generaI purpose metric screw threads except tolerances;
b) For tolerances on ISO general purpose metric screw threads a new standard, that is IS 14962
to be published in five parts, that is (Parts 1 to 5) by adopting ISO 965 (Part 1) : 1998,
ISO 965 (Part 2) : 1998, ISO 965 (Part 3) : 1998, ISO 965 (Part 4) : 1998 and
ISO 965 (Part 5) :1998 respectively; and
c) After the publication of above standards IS 4218 (Part 5) :1979 and IS 4218 (Part 6) :1978
stand withdrawn.
The text of ISO Standard has been approved as suitable for publication as an Indian Standard without
deviations. In the adopted standard, certain conventions are not identical to those used in Indian
Standard. Attention is especially drawn to the following:
a) Wherever the words ‘International Standard’ appear referring to this standard, they should be
read as ‘1ndian Standard’.
b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practice
is to use a full point (.) as the decimal marker.
In this adopted standard, re ference appears to certain International Standards for which Indian

Standards also exist. The corresp onding Indian Standards which are to be substituted in their place

are listed below along with their degree of equivalence for the editions indicated:
International Corresponding Degree of
Standard Indian Standard Equivalence
ISO 68-1:1998 IS 4218 (Part 1) :2001 ISO general purpose metric screw Identical
threads: Part 1 Basic profile (second revision)
ISO 261:1998 IS 4218 (Part 2) :2001 ISO general purpose metric screw do
threads: Part 2 General plan (second revision)
ISO 262:1998 IS 4218 (Part 4) :2001 ISO general purpose metric screw do
threads: Part 4 Selected sizes for screws, bolts and nuts
(second revision)
ISO 724:1993 IS 4218 (Part 3) :1999 ISO general purpose metric screw do
threads: Part 3 Basic dimensions (second revision)
ISO 898-1 :’) IS 1367 (Part 3) “ Technical supply conditions for threaded do
steel fasteners : Part 3 Mechanical properties of fasteners
made of carbon steel and alloy steel — Bolts, screws and
studs (fourth revision)
‘)Tobepublished(RevisionofISO898-1: 1988).
2)Tobepublished[RevisionofIS1367(Part3):1991].
(Continued on third cover)
IS 14962 ( Part 1 ) :2001
ISO 965-1 :1998
Indian Standard
ISO GENERAL PURPOSE METRIC SCREW
THREADS — TOLERANCES
PART 1 PRINCIPLES AND BASIC DATA
1 Scope
This part of ISO 965 specifies the basic profile for ISO general purpose metric screw threads (M) conforming to
ISO 261.
The tolerance system refers to the basic profile inaccordance with ISO 68-1.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this part of
ISO 965. At the time of publication the editions indicated were valid. All standards are subject to revision, and
parties to agreements based on this part of ISO 965 are encouraged to investigate the possibility of applying the
most recent editions ofthe standards Indicated below. Members of IEC and ISO maintain registers ofcurrently valid
International Standards.
ISO 68-1:1998, ISO general purpose scre w threads — Basic profile — Part 1:Metric screw threads.

ISO 261:” 998, 1S0 general purpose me tric screw threads — General plan.
ISO 262:” 998, ISO general purpose metric screw threads — Selected sizes for screws, bolts and nuts.
ISO 724: 993, ISO general purpose metric screw threads — Basic dimensions.
ISO 898-1 :—l ~,Mechanical properties of fasteners made of carbon steel and alloy steel — Part 1: Bolts, screws
and studs.
ISO 965-2:1998, ISO general purpose metric screw threads — Tolerances — Part 2: Limits of sizes for general
purpose bolt and nut threads — Medium quality.
ISO 965-3:1998, ISO general purpose metric screw threads — Tolerances — Pari 3: Deviations for constructional
screw threads.
ISO 1502:1996, /S0 general purpose metric screw threads — Gauges and gauging.
ISO 5408:1983, Cylindrical screw threads — Vocabulary.
1) Tobepublished.(RevisionofISO898-1:1988)

1
IS 14962 ( Part 1 ) :2001
ISO 965-1 : 1998
3 Definitions and symbols
3.1 Definitions
For Me purpose ofthis part of ISO 965 the definitions given in ISO 5408 apply.
3.2 Symbols
The following symbols are used:
I Symbol I Explanation I
I
D I basicrnaiordiarneterofinternalthread I
D, basicminordiameterofinternalthread
D2 basicpitchdiameterofinternalthread
d basicmajordiameterofexternalthread
I d, I basicminordiameterofexternalthread I
I d2 I basicpitchdiameterofexternalthread I
I dq I minordiameterofexternalthread I
P pitch
Ph lead
I H I heightoffundamentaltriangle I
I s I designationforthreadengagementgroup“short” I
I N I designationforthreadengagementgroup“normal” I
l==L- designationforthreadengagementgroup“long”

T tolerance

TD1,TD2 I
tolerancesforD1,D2,d,d2
Tall,Tdz
I ei,El lowerdeviations(seefigure1) I
I
es,ES upperdeviations(seefigure1)
R rootradiusofexternalthread
+ c roottruncationofexternalthread

2
IS 14962 ( Part 1 ) :2001
ISO 965-1 :1998
Figure 1— Position of tolerances with respect to zero line (basic size)
4 Structure of the tolerance system
The system gives tolerances defined by tolerance grades and tolerance positions and a selection of grades and
positions.
The system provides for:
a) a series oftolerance grades for each of the four screw thread diameters, as follows:
Tolerance grades
D1 4, 5, 6, 7, 8
d 4, 6, 8
D2 4, 5, 6, 7, 8

d2 3, 4, 5, 6, 7, 8, 9

Detailsoftolerance grades and combinations oftolerance gradesforpitchand crestdiameters accordingtotolerance quality
andlengthofengagement grouprequired,withorderofpreference, are showninclause 12.
b) Series oftolerance positions:
— Gand Hforinternalthreads;
— e,f,gandhforexternalthreads.
The established tolerance positions comply with the need of current coating thickness and with the demands of easy
assembly.
c) Selection of recommended combinations of grades and positions (tolerance classes) giving the commonly used
tolerance qualities fine, medium and coarse for the three groups of length of thread engagement short, normal
and long. Moreover a further selection of tolerance classes is given for commercial bolt and nut threads.
Tolerance classes other than those shown in clause 12 are not recommended and shall only be used for
special cases.

3
..-
IS 14962 ( Part 1 ) :2001
ISO 965-1 :1998
.
5 Designation
5.1 General
The complete designation fora screw thread comprises a designation forthe thread system and size, a designation for
the thread tolerance class followed byfurther individual items ifnecessary.
5.2 Designation of single-start screw threads
A screw thread complying with the requirements of the International Standards for ISO general purpose metric screw
threads according to ISO 68-1, ISO 261, ISO 262, ISO 724, ISO 965-2 and ISO 965-3 shall be designated by the letter
M followed by the value of the nominal diameter and of the pitch, expressed in millimetres and separated by the
sign “x”.
EXAMPLE: M8 X 1,25
For coarse pitchthreads listed inISO 261, the pitch maybe omitted.
EXAMPLE: M8
The tolerances class designation comprises a class designation for the pitch diameter tolerance followed by a class
designation forthe crest diameter tolerance.
Each class designation consists of
— a figure indicating the tolerance grade;
— a letter indicating the tolerance position, capital for internal threads, small for external threads.
Ifthe two class designations forthe pitchdiameter and crest diameter (major orminor diameter forinternal and external
threads respectively) are the same itisnotnecessary to repeat the symbols.
EXAMPLES:
Externalthread
MIOXI -
TT

Thread of 10mmnomina~diameter having apitch of 1mm____.I_ ‘g ‘g

1 I
Tolerance class for pitch diameter
J
Tolerance c(ass for major diameter
MIO - ‘g
~T
Thread of 10mmnominaldiameter inthe coarse pitch series
I
Tolerance c~assfor pitch andmajor diameters
Internalthread
MIOXI - SH
TT
Thread of 10mmnominaldiameter having apitch of 1mm~ ‘“
Tolerance c~assfor pitch diameter I I
I
Tolerance c~assfor minordiameter
MIO - 6“
‘T
Thread of 10mmnominal diameter inthe coarse pitch series
I
ToLerance c(ass for Ditchandminor diameters
IS 14962 ( Part 1 ) :2001
ISO 965-1 :1998
Afitbetween threaded parts isindicated bythe internal thread tolerance class followed bythe external thread tolerance
class separated bya stroke.
EXAMPLE:
M6 – 6H/6g
M20 x 2– 61-t/5g6g
The absence oftolerance class designation means that tolerance quality “medium” withthe following tolerance classes
are specified:
Internal threads
— 5H forthreads up to and including Ml ,4;
— 6H forthreads Ml,6 and larger.
NOTE Exceptforthreads withpitchP=0,2 mmforwhichthetolerance grade4 isdefinedonly(seetables3and 5)
External threads
6h for threads up to and including Ml ,4;
6g for threads Ml,6 and larger.
The designation forthe group of length ofthread engagement “short”S and “long”Lshould be added to the tolerance
class designation separated by a dash.
EXAMPLE: M20x2–5H– S
M6 – 7H/7g6g – L
The absence ofthe designation forthe group oflength ofthread engagement means the group “normal”N isspecified.
5.3 Designation of multiple-sta r t screw threads

Multiple-start metric screw threads shall be designated by the letter M followed by the value of the nominal diameter,
the sign x, the letters Ph and the value ofthe lead, the letter P and the value ofthe pitch (axial distance between two
neighboring flanks in the same direction) a dash, and the tolerance class. Nominal diameter, lead and pitch are
ex~ressed ii millimetres
EXAMPLE: M16 X Ph3Pl,5–6H
For extra clarity the number ofstarts i.e. the value of ~ may be added inverbal form and inparenthesis.
EXAMPLE: M16 x Ph3Pl,5 (two starts) - 6H
5.4 Designation of the left hand threads
When lefthand threads are specified the letters LH shall be added tothe thread designation, separated by a dash.
EXAMPLES: M8 X 1– LH
M6 X 0,75- 5h6h – S– LH
M14x Ph6P2–7H– L–LH
Ml 4 x Ph6P2 (three starts) – 7H– L– LH
5