ISO 2903:1993

ISO metric trapezoidal screw threads — Tolerances

Specifies a tolerance system for threads according to ISO 2902; the system does not apply to threads with special requirements on axial displacement (e.g. lead screws); gives the structure of the system and tabulates pitches from 1.5 up to and including 44, comprises basic major diameters over 5.6 mm up to and including 355 mm; includes recommended tolerance classes for bolt and nut threads.

Filetages métriques trapézoïdaux ISO — Tolérances

La présente Norme internationale établit un système de tolérances pour filetages métriques trapézoïdaux conformes à l'ISO 2902. Les tolérances se rapportent au profil de base conforme à l'ISO 2901. Le système de tolérances ne s'applique pas aux filetages trapézoïdaux ayant des exigences spéciales de déplacement axial, par exemple vis-mère.

Metrski trapezni navoj ISO - Tolerance

General Information

• Status: Withdrawn
• Publication Date: 27-Oct-1993
• Withdrawal Date: 27-Oct-1993
• ICS: 21.040.10 - Metric screw threads
• Technical Committee: ISO/TC 1 - Screw threads
• Drafting Committee: ISO/TC 1 - Screw threads
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 12-Aug-2016
• Ref Project: SIST ISO 2903:1998 - ISO metric trapezoidal screw threads -- Tolerances

Relations

• Revised: ISO 2903:2016 - ISO metric trapezoidal screw threads — Tolerances
• Effective Date: 04-Nov-2015
• Revises: ISO 2903:1977 - ISO metric trapezoidal screw threads — Tolerances
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL
STANDARD
Second edition
1993-11-01
ISO metric trapezoidal screw threads -
Tolerantes
Filetages m&t-iques trapkzoiiiaux ISO - Tokrances
Reference number
ISO 2903:1993(E)

---------------------- Page: 1 ----------------------
ISO 2903:1993(E)
Contents
Page
1
1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Normative references . . . . . . . . . . . . . . . .*. 1
1
3 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
4 Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
5 Structure of the tolerante System . . . . . . . . . . . . .*.
6 Tolerante grades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*. 2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
7 Tolerante positions
Lengths of thread engager ient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*. 3
8
9 Crest and root diameter to erances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3
IO Pitch diameter tolerantes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
11 Recommended tolerante classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12 Multiple-Start threads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
9
13 Formulae .,.,,. ”
14 Designation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
0 ISO 1993
All rights reserved. No part of this publication may be reproduced or utilized in any form or
by any means, electronie or mechanical, including photocopying and microfiim, without per-
mission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-l 211 Geneve 20 l Switzerland
Printed in Switzerland

---------------------- Page: 2 ----------------------
ISO 2903:1993(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide
federation of national Standards bodies (ISO member bodies). The work
of preparing International Standards is normally carried out through ISO
technical committees. Esch 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, governmental
and non-governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 2903 was prepared by Technical Committee
lSO/TC 1, Screw threads, Sub-Committee SC 2, Tolerantes.
This second edition cancels and replaces the first edition
(ISO 2903:1977), tables 1 and 7 of which have been technically revised.

---------------------- Page: 3 ----------------------
This page intentionally left blank

---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 2903:1993(E)
ISO metric trapezoidal screw threads - Tolerantes
4 Symbols
1 Scope
This International Standard specifies a tolerante sys- (See figures 1 to 4)
tem for metric trapezoidal screw threads in accord-
basic major diameter of nut thread, in millimetres
ante with ISO 2902. The tolerantes refer to the basic
4
Profile ISO 2901.
basic minor diameter of nut thread, in millimetres
Dl
basic pitch diameter of nut thread, in millimetres
02
The tolerante System does not apply to trapezoidal
d basic major diameter of bolt thread, in millimetres
screw threads with special requirements on axial dis-
placement, for example lead screws.
basic minor diameter of bolt thread, in millimetres
4
basic pitch diameter of bolt thread, in millimetres
d2
P pitch, in millimetres
lead, in millimetres
ph
2 Normative references
N designation for thread engagement group
“ Normal ”
The following Standards contain provisions which,
l- designation for thread engagement group
through reference in this text, constitute provisions
” Long ”
of this International Standard. At the time of publi-
thread engagement, in millimetres
lN
cation, the editions indicated were valid. All Standards
T tolerante, in micrometres
are subject to revision, and Parties to agreements
based on this International Standard are encouraged
T
Dl
to investigate the possibility of applying the most re-
T
DZ
cent editions of the Standards indicated below.
.
tolerantes for D,, D,, d, da, dz (for D, no tol-
Td
Members of IEC and ISO maintain registers of cur-
erances are specified), in micrometres
rently valid International Standards.
Td3
T
d2
ISO 965-1: 1980, /SO general purpose metric screw
threads - Tolerantes - Part 1: Principles and basic
ei, EI lower deviations (EI for nut threads is equal
data.
to Zero), in micrometres
upper deviations, in micrometres
es, ES
ISO 2901: 1993, ISO metric trapezoidal screw threads
- Basic Profile and maximum material profiles.
ISO 2902:1977, ISO metric trapezoidal screw threads
- General plan.
ISO 5408: 1983, Cylindrical screw threads - Vocabu- 5 Structure of the tolerante System
.
lw
The System is based on the tolerante System for ISO
general-purpose metric screw threads of ISO 965-1,
completed with tolerante positions c and e, and with
values for pitches above 6 mm.
3 Definitions
The recommended tolerante classes are, however,
For the purposes of this International Standard, the not the same as those for ISO metric screw threads
definitions given in ISO 5408 apply. in ISO 965-1.

---------------------- Page: 5 ----------------------
ISO 2903:1993(E)
6 Tolerante grades
7 Tolerante positions
Pitch line
The following tolerante grades are established:
Tolerante grades
es
Minor diameter of nut threads D, : 4
ei
Major diameter of bolt threads d : 4
Pitch diameter of nut threads D, : 7 8 9
Pitch diameter of bolt threads 4 : 7 8 9
(6)
Figure 1 - Tolerante positions with respect to
Minor diameter of bolt threads 4 : 7 8 9
zero line (basic size)
Tolerante grade 6 for the pitch diameter (4) of the
bolt thread has been included only as a means to es-
The following tolerante positions are standardized for
tablish the pitch diameter tolerantes of grades 7, 8
the pitch diameter.
and 9. See 13.4.2.
a) For nut threads: H with zero fundamental deviation
The tolerante grade for the minor diameter (4) of the
(see figure 2 and table 1).
bolt thread is always the Same as for the pitch
diam-
eter (d,).
b) For both threads: c and e with negative funda-
mental deviation (see figure 3 and table 1).
However, the values for Td3 and Td2 are not the same
for a same grade because Td3 = 1 ,25Tdz + lesl.
The tolerante Position for the minor diameter D, and
t
the major diameter D, of the nut threads is always
H, i.e. with zero fundamental deviation. The tolerante
Position for the major diameter d and minor diameter
4 of the bolt threads is in all cases h, i.e. with zero
fundamental deviation, and it is independent of the
tolerante Position of the pitch diameter.
al 01 a’ I
Nut threads with tolerante Position H for the pitch diameter
Figure 2 -

---------------------- Page: 6 ----------------------
ISO 2903:1993(E)
e C
c 4
h
u -Cl II
Bolt threads with tolerante positions c and e for the pitch diameter
Figure 3 -
8 Lengths of thread engagement
rable 1 - Fundamental deviations for the pitch
The length of thread engagement is classified into the
diameter of nut threads and bolt threads
groups N or L, in accordance with table2.
Fundamental deviation
r
Bolt thread
Nut thread
Pitch
9 Crest and root diameter tolerantes
4
Dz
P
H C e
9.1 Minor diameter tolerantes of nut thread
EI es es
(TOI)
mm
Pm
For the minor diameter tolerante of the nut thread,
0 -140 -67
lt5
TD,, there is only one tolerante grade, 4 (see table 3).
2 0 -150 -71
0 -170 -85
3
9.2 Major diameter tolerantes of bolt thread
-190 - 95
4 0
-212 -106
5 0 (7 1
d
-236 -118
6 0
For the major diameter tolerante of the bolt thread,
-125
7 0 -250
Td, there is only one tolerante grade, 4 (see table4).
-132
8 0 -265
-140
9 0 -280
9.3 Minor diameter tolerantes of bolt thread
10 0 -300 -150
12 0 -335 -160
ITd3)
14 0 -355 -180
For the minor diameter tolerante of the bolt thread,
-375 -190
16 0
TdS, there are three tolerante grades, 7, 8, and 9, in
-400 -200
18 0
-212
20 0 -425 accordance with table 5.
-224
22 0 -450
-236
24 0 -475
10 Pitch diameter tolerantes
-250
28 0 -500
-265
32 0 -530
For the pitch diameter tolerantes there are three tol-
36 0 -560 -280
erance grades, 7, 8 and 9 for nut threads, in accord-
-300
40 0 -600
ante with table 6, and four tolerante grades, 6, 7, 8
-315
44 0 -630
and 9 for bolt threads, in accordance with table7.

---------------------- Page: 7 ----------------------
ISO 2903:1993(E)
Table 2 - Lengths of thread engagement
Dimensions in millimetres
Groups of lengths of thread engagement, z
Basic major diameter Pitch
N L
d P
over up to and incl. over up to and incl. over
5 15 15
lt5
11,2 2 6 19
56 19
3 10 28 28
2 24
8 24
3 11 32
32
11,2 22,4 4 15 43
43
5 18 53 53
8 30 85 85
3 12 36 36
5 21 63 63
6 25 75 75
22,4 45
7 30 85 85
8 34 100 100
10 42 125 125
12 50 150 150
3 15 45 45
4 19 56 56
8 38 118 118
9 132
43 132
45 90 10 140
50 140
12 170
60 170
14
67 200 200
16 75 236 236
18
...

SLOVENSKI STANDARD
SIST ISO 2903:1998
01-avgust-1998
Metrski trapezni navoj ISO - Tolerance
ISO metric trapezoidal screw threads -- Tolerances
Filetages métriques trapézoïdaux ISO -- Tolérances
Ta slovenski standard je istoveten z: ISO 2903:1993
ICS:
21.040.10 Metrski navoji Metric screw threads
SIST ISO 2903:1998 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST ISO 2903:1998

---------------------- Page: 2 ----------------------

SIST ISO 2903:1998
INTERNATIONAL
STANDARD
Second edition
1993-11-01
ISO metric trapezoidal screw threads -
Tolerantes
Filetages m&t-iques trapkzoiiiaux ISO - Tokrances
Reference number
ISO 2903:1993(E)

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

SIST ISO 2903:1998
ISO 2903:1993(E)
Contents
Page
1
1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 Normative references . . . . . . . . . . . . . . . .*. 1
1
3 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
4 Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
5 Structure of the tolerante System . . . . . . . . . . . . .*.
6 Tolerante grades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*. 2
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
7 Tolerante positions
Lengths of thread engager ient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*. 3
8
9 Crest and root diameter to erances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3
IO Pitch diameter tolerantes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9
11 Recommended tolerante classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
12 Multiple-Start threads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
9
13 Formulae .,.,,. ”
14 Designation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
0 ISO 1993
All rights reserved. No part of this publication may be reproduced or utilized in any form or
by any means, electronie or mechanical, including photocopying and microfiim, without per-
mission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-l 211 Geneve 20 l Switzerland
Printed in Switzerland

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

SIST ISO 2903:1998
ISO 2903:1993(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide
federation of national Standards bodies (ISO member bodies). The work
of preparing International Standards is normally carried out through ISO
technical committees. Esch 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, governmental
and non-governmental, in liaison with ISO, also take part in the work. ISO
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard ISO 2903 was prepared by Technical Committee
lSO/TC 1, Screw threads, Sub-Committee SC 2, Tolerantes.
This second edition cancels and replaces the first edition
(ISO 2903:1977), tables 1 and 7 of which have been technically revised.

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

SIST ISO 2903:1998
This page intentionally left blank

---------------------- Page: 6 ----------------------

SIST ISO 2903:1998
INTERNATIONAL STANDARD ISO 2903:1993(E)
ISO metric trapezoidal screw threads - Tolerantes
4 Symbols
1 Scope
This International Standard specifies a tolerante sys- (See figures 1 to 4)
tem for metric trapezoidal screw threads in accord-
basic major diameter of nut thread, in millimetres
ante with ISO 2902. The tolerantes refer to the basic
4
Profile ISO 2901.
basic minor diameter of nut thread, in millimetres
Dl
basic pitch diameter of nut thread, in millimetres
02
The tolerante System does not apply to trapezoidal
d basic major diameter of bolt thread, in millimetres
screw threads with special requirements on axial dis-
placement, for example lead screws.
basic minor diameter of bolt thread, in millimetres
4
basic pitch diameter of bolt thread, in millimetres
d2
P pitch, in millimetres
lead, in millimetres
ph
2 Normative references
N designation for thread engagement group
“ Normal ”
The following Standards contain provisions which,
l- designation for thread engagement group
through reference in this text, constitute provisions
” Long ”
of this International Standard. At the time of publi-
thread engagement, in millimetres
lN
cation, the editions indicated were valid. All Standards
T tolerante, in micrometres
are subject to revision, and Parties to agreements
based on this International Standard are encouraged
T
Dl
to investigate the possibility of applying the most re-
T
DZ
cent editions of the Standards indicated below.
.
tolerantes for D,, D,, d, da, dz (for D, no tol-
Td
Members of IEC and ISO maintain registers of cur-
erances are specified), in micrometres
rently valid International Standards.
Td3
T
d2
ISO 965-1: 1980, /SO general purpose metric screw
threads - Tolerantes - Part 1: Principles and basic
ei, EI lower deviations (EI for nut threads is equal
data.
to Zero), in micrometres
upper deviations, in micrometres
es, ES
ISO 2901: 1993, ISO metric trapezoidal screw threads
- Basic Profile and maximum material profiles.
ISO 2902:1977, ISO metric trapezoidal screw threads
- General plan.
ISO 5408: 1983, Cylindrical screw threads - Vocabu- 5 Structure of the tolerante System
.
lw
The System is based on the tolerante System for ISO
general-purpose metric screw threads of ISO 965-1,
completed with tolerante positions c and e, and with
values for pitches above 6 mm.
3 Definitions
The recommended tolerante classes are, however,
For the purposes of this International Standard, the not the same as those for ISO metric screw threads
definitions given in ISO 5408 apply. in ISO 965-1.

---------------------- Page: 7 ----------------------

SIST ISO 2903:1998
ISO 2903:1993(E)
6 Tolerante grades
7 Tolerante positions
Pitch line
The following tolerante grades are established:
Tolerante grades
es
Minor diameter of nut threads D, : 4
ei
Major diameter of bolt threads d : 4
Pitch diameter of nut threads D, : 7 8 9
Pitch diameter of bolt threads 4 : 7 8 9
(6)
Figure 1 - Tolerante positions with respect to
Minor diameter of bolt threads 4 : 7 8 9
zero line (basic size)
Tolerante grade 6 for the pitch diameter (4) of the
bolt thread has been included only as a means to es-
The following tolerante positions are standardized for
tablish the pitch diameter tolerantes of grades 7, 8
the pitch diameter.
and 9. See 13.4.2.
a) For nut threads: H with zero fundamental deviation
The tolerante grade for the minor diameter (4) of the
(see figure 2 and table 1).
bolt thread is always the Same as for the pitch
diam-
eter (d,).
b) For both threads: c and e with negative funda-
mental deviation (see figure 3 and table 1).
However, the values for Td3 and Td2 are not the same
for a same grade because Td3 = 1 ,25Tdz + lesl.
The tolerante Position for the minor diameter D, and
t
the major diameter D, of the nut threads is always
H, i.e. with zero fundamental deviation. The tolerante
Position for the major diameter d and minor diameter
4 of the bolt threads is in all cases h, i.e. with zero
fundamental deviation, and it is independent of the
tolerante Position of the pitch diameter.
al 01 a’ I
Nut threads with tolerante Position H for the pitch diameter
Figure 2 -

---------------------- Page: 8 ----------------------

SIST ISO 2903:1998
ISO 2903:1993(E)
e C
c 4
h
u -Cl II
Bolt threads with tolerante positions c and e for the pitch diameter
Figure 3 -
8 Lengths of thread engagement
rable 1 - Fundamental deviations for the pitch
The length of thread engagement is classified into the
diameter of nut threads and bolt threads
groups N or L, in accordance with table2.
Fundamental deviation
r
Bolt thread
Nut thread
Pitch
9 Crest and root diameter tolerantes
4
Dz
P
H C e
9.1 Minor diameter tolerantes of nut thread
EI es es
(TOI)
mm
Pm
For the minor diameter tolerante of the nut thread,
0 -140 -67
lt5
TD,, there is only one tolerante grade, 4 (see table 3).
2 0 -150 -71
0 -170 -85
3
9.2 Major diameter tolerantes of bolt thread
-190 - 95
4 0
-212 -106
5 0 (7 1
d
-236 -118
6 0
For the major diameter tolerante of the bolt thread,
-125
7 0 -250
Td, there is only one tolerante grade, 4 (see table4).
-132
8 0 -265
-140
9 0 -280
9.3 Minor diameter tolerantes of bolt thread
10 0 -300 -150
12 0 -335 -160
ITd3)
14 0 -355 -180
For the minor diameter tolerante of the bolt thread,
-375 -190
16 0
TdS, there are three tolerante grades, 7, 8, and 9, in
-400 -200
18 0
-212
20 0 -425 accordance with table 5.
-224
22 0 -450
-236
24 0 -475
10 Pitch diameter tolerantes
-250
28 0 -500
-265
32 0 -530
For the pitch diameter tolerantes there are three tol-
36 0 -560 -280
erance grades, 7, 8 and 9 for nut threads, in accord-
-300
40 0 -600
ante with table 6, and four tolerante grades, 6, 7, 8
-315
44 0 -630
and 9 for bolt threads, in accordance with table7.

---------------------- Page: 9 ----------------------

SIST ISO 2903:1998
ISO 2903:1993(E)
Table 2 - Lengths of thread engagement
Dimensions in mill
...

NORME IS0
2903
INTERNATIONALE
DeuxiGme hdition
1993-l l-01
Filetages mbtriques trapbzoiidaux IS0 -
Tolhrances
IS0 metric trapezoidal screw threads - Tolerances
Numkro de rkfhence
IS0 2903:1993(F)

---------------------- Page: 1 ----------------------
IS0 2903:1993(F)
Sommaire
Page
1
1 Domaine d ’application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
2 Rkf&ences normatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1
3 Dkfinitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*.
4 Symboles . I
5 Structure du systkme de tokrances . I
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
6 Qualit& de tokrances . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2
7 Positions de tokrances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
................... 3
8 Longueurs en prise .
9 Tokrances sur les diamgtres au sommet et A fond de filet . . . . 4
4
IO Tokrances sur le diam&re sur flancs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8
11 Tolkrances recommandkes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
12 Filetages 6 plusieurs filets
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
13 Formules
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IO
14 Designation
0 IS0 1993
Droits de reproduction reserves. Aucune partie de cette publication ne peut etre reproduite
ni utilisee sous quelque forme que ce soit et par aucun pro&de, electronique ou mecanique,
y compris la photocopie et les microfilms, sans I ’accord ecrit de I ’editeur.
Organisation internationale de normalisation
Case Postale 56 l CH-1211 Geneve 20 l Suisse
Imprime en Suisse
ii

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IS0 2903:1993(F)
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 en general confiee aux
comites techniques de I’ISO. Chaque comite membre interesse par une
etude a le droit de faire pat-tie du comite technique tree a cet effet. Les
organisations internationales, gouvernementales et non gouvernemen- ,
tales, en liaison avec I’ISO participent egalement aux travaux. L ’ISO colla-
bore etroitement avec la Commission electrotechnique internationale (CEI)
en ce qui concerne la normalisation electrotechnique.
Les projets de Normes internationales adopt& par les comites techniques
sont soumis aux comites membres pour vote. Leur publication comme
Normes internationales requiert I’approbation de 75 % au moins des co-
mites membres votants.
La Norme internationale IS0 2903 a ete elaboree par le comite technique
lSO/TC 1, Filetages, sous-comite SC 2, Tobrances.
Cette deuxieme edition annule et remplace la premiere edition
(IS0 2903:1977), dont les tableaux 1 et 7 ont fait I’objet d ’une revision
technique.
..*
III

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NORME INTERNATIONALE IS0 2903:1993(F)
Filetages mbtriques traphzoiidaux IS0 - Tokrances
1 Domaine d ’application 4 Symboles
La presente Norme internationale etablit un systeme (Voir figures 1 a 4)
de tolerances pour filetages metriques trapezo ’idaux
diametre exterieur de base du filetage de I ’ecrou,
conformes a I’ISO 2902. Les tolerances se rapportent
D4
en millimetres
au profil de base conforme a I’ISO 2901.
diametre interieur de base du filetage de I ’ecrou,
Dl
Le systeme de tolerances ne s ’applique pas aux file-
en millimetres
tages trapezo ’idaux ayant des exigences speciales de
diametre sur flancs de base du filetage de I ’ecrou,
D2
deplacement axial, par exemple vis-mere.
en millimetres
d diametre exterieur de base du filetage de la vis,
en millimetres
diametre interieur de base du filetage de la vis,
d3
2 R6fkences normatives
en millimetres
diametre sur flancs de base du filetage de la vis,
d2
Les normes suivantes contiennent des dispositions
en millimetres
qui, par suite de la reference qui en est faite, consti-
P pas du profil, en millimetres
tuent des dispositions valables pour la presente
pas helicoi ’dal, en millimetres
Nor-me internationale. Au moment de la publication,
Ph
les editions indiquees etaient en vigueur. Toute
designation pour le groupe de longueurs en prise
N
norme est sujette a revision et les parties prenantes dites wormales)
des accords fond& sur la presente Norme internatio-
L designation pour le groupe de longueurs en prise
nale sont invitees a rechercher la possibilite d ’appli-
dites ((Iongues)
quer les editions les plus recentes des normes
longueur en prise, en millimetres
IN
indiquees ci-apres. Les membres de la CEI et de I’ISO
T tolerance, en micrometres
possedent le registre des Normes internationales en
vigueur a un moment donne.
T
Dl
T
02
IS0 965-l : 1980, Filetages mktriques IS0 pour usages tolerances sur D,, D,, d, d3, d2 (pour D, au-
Td
tune tolerance nest specifiee), en micro-
g&Graux - Tolhances - Partie I: Principes et don-
!
metres
&es fondamen tales.
Td3
T
d2
I
IS0 2901: 1993, Filetages mbtriques trapkzoidaux IS0
- Profil de base et profils B maximum de mat&e.
ei, EI &arts inferieurs (pour le filetage de I ’ecrou,
EI est egal a zero), en micrometres
IS0 2902: 1977, Filetages mhtriques traphzoidaux IS0
es, ES &arts superieurs, en micrometres
- Vue d ’ensemble.
I SO 5408: 1983, Filetages cylindriques - Vocabulaire.
5 Structure du systbme de tokrances
Le systeme est base sur le systeme de tolerances
3 Dbfinitions
pour filetages metriques IS0 pour usages generaux
de I’ISO 965-1, complete par les &arts fondamentaux
Pour les besoins de la presente Norme internationale, c et e, et par les valeurs des pas au-dessus de
les definitions donnees dans I’ISO 5408 s ’appliquent.
6 mm.
1

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IS0 2903:1993(F)
Les tolerances recommandees ne sont cependant pas
7 Positions de tokrances
les memes que celles pour les filetages metriques
IS0 suivant I’ISO 965-l.
ES
Ligne primitive
6 &alit& de tolbrances
E/O
Les qualites de tolerances suivantes sont etablies:
es
Qualitth de tolhrances
ei .
Diametre interieur du filetage
4
de l’ecrou, D, :
Diamktre extbrieur du filetage
4
Figure 1 - Positions de tolkances par rapport h
de la vis, d :
la ligne z&o (dimensions de base)
Diametre sur flancs du filetage
7 8 9
de kcrou, D, :
Diam&re sur flancs du filetage
7 8 9
(6)
Les positions de tolerances suivantes sont normali-
de la vis, d2 :
sees pour le diametre sur flancs.
Diamktre intkrieur du filetage
7 8 9
de la vis, d3 :
Pour les ecrous: H avec &art fondamental zero
a)
(voir figure 2 et tableau I).
La qualite de tolerance 6 du diametre sur flancs du
filetage de la vis (4) est incluse seulement comme
Pour les vis: c et e avec &art fondamental negatif
b)
un moyen pour etablir les tolerances sur le diametre
(voir figure 3 et tableau I).
sur flancs de qualites de tolerances 7, 8 et 9. Voir
13.4.2.
La position de la tolerance pour le diametre interieur
et le diametre exterieur Da de I’ecrou est toujours
La qualite de tolerance du diametre interieur de la vis Dl
H c ’est-a-dire avec &art fondamental zero. La po-
I
(4) est toujours la meme que celle du diametre sur
sition de la tolerance pour le diametre exterieur d et
flancs (4).
le diametre interieur G$ de la vis est toujours h, c ’est-
a-dire avec &art fondamental zero, independamment
Les valeurs de 7” et Td2 ne sont cependant pas les
memes pour une meme qualite, parce que de la position de la tolerance sur le diametre sur
Td3 = 1 ,25Td, + lesl. flancs.
Figure 2 - Filetage de kcrou avec position de tokrance H pour le diamhtre sur flancs

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IS0 2903:1993(F)
Figure - Filetage de la vis avec positions de tolhances c et e pour le diamktre flancs
3 sur
Tableau 1 - harts fondamentaux pour le
diamhtre sur flancs du filetage de I’kcrou et de la
vis
hart fondamental
Pas icrou Vis
P
D2 4
H C e
EI es es
mm
CLm Pm Pm
1,5 0 -140
-67
2 0 -150
-71
3 0
-170 -85
4 0
-190 -95
5 0
-212 -106
6
0 -236 -118
7
0 -250 -125
8 0 -265 -132
9 0 -280 -140
10 0 -300
-150
12 0 -335
-160
14 0
-355 -180
16 0
-375 -190
18 0
-400 -200
20 0
-425 -212
22 0
-450 -224
24 0
-475 -236
28
0 -500 -250
32 0 -530 -265
36 0 -560 -280
40 0 -600 -300
44 0 -630 -315
3

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IS0 2903:1993(F)
seule la qualiti: de toI&ante 4 est prhue (voir
8 Longueurs en prise
tableau 4).
Les longueurs en prise sont classbes en deux grou-
pes, N et L, conformhment au tableau 2.
9.3 Tolhrances sur le diamhtre intbrieur de
la vis (T,,)
9 Tokrances sur les diamhtres au
sommet et 6 fond de filet
Pour la tolhance Td3 sur le diametre intbrieur de la vis,
trois qualit& sont prkvues, $ savoir 7, 8 et 9, confor-
mement au tableau 5.
9.1 Tokrances sur le diam&re intkrieur de
krou (T,,)
Pour la tolkrance TD, sur le diamktre intkrieur de
10 Tokrances sur le diamktre sur flancs
l’kcrou, seule la quake de tokance 4 est prkvue (voir
tableau 3).
Pour les tolkrances sur le diamktre sur flancs, trois
qualit& de tokrances sont prhues, A savoir 7, 8 et
9.2 Tolbrances sur le diamhtre extbrieur de 9 pour les filetages de kcrou, conformkment au ta-
bleau 6, et quatre qualith de tokrances, 6, 7, 8 et 9
la vis (Td)
pour les filetages de la vis, conformement au
Pour la tolhance Td sur le diamhtre ext&ieur de la vis, tableau 7.
Tableau 2 - Longueurs en prise
nimancinnc nn millimhtrn
VII I IGI 13lUI I3 Lil I I I llllll I ItiLl b
Longueurs en prise, 2
Diamhtre extbrieur de base Pas
N L
d P
supkrieur a
de (exclu) a (inclus) de (exclu) 3 (inclus)
(exclu)
1,5 5 15 15
5,6 II,2 2 6 19 19
3 10 28 28
2 8 24 24
3 11 32 32
II,2 22,4 4 15 43 43
5 18 53 53
8 30 85 85
3 12 36 36
5 21 63 63
6 25 75 75
22,4 45
7 30 85 85
8 34 100 100
10 42 125 125
12 50 150 150
3 15 45 45
4 19 56 56
8 38 118 118
9 43 132 132
45 90 10 50 140 140
12 60 170 170
14 67 200 200
16 75 236 236
18 85 265 265

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