ISO 4468:2009
(Main)Gear hobs — Accuracy requirements
Gear hobs — Accuracy requirements
ISO 4468:2009 specifies requirements for the accuracy of general-purpose hobs of 0,5 module to 40 module. These hobs are intended for producing gears which conform to ISO 53 and ISO 54. ISO 4468:2009 applies to hobs for spur and helical gears and to solid (monobloc) and inserted blade hobs.
Fraises-mères — Exigences d'exactitude
Polžasta frezala - Zahteve po točnosti
General Information
Relations
Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 4468
Second edition
2009-06-01
Gear hobs — Accuracy requirements
Fraises-mères — Exigences d'exactitude
Reference number
ISO 4468:2009(E)
©
ISO 2009
---------------------- Page: 1 ----------------------
ISO 4468:2009(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
COPYRIGHT PROTECTED DOCUMENT
© ISO 2009
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2009 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 4468:2009(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Accuracy requirements. 4
5 Derivation of allowable values . 5
5.1 General. 5
5.2 Tests 1-7 . 5
5.3 Tests 9, 11, 11A, 12, 12A . 6
5.4 Test 9B . 6
5.5 Tests 8, 8A, 9B, 10, 13, 14, 15 and 16. 6
Bibliography . 32
© ISO 2009 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO 4468:2009(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. 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, 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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 4468 was prepared by Technical Committee ISO/TC 60, Gears, Subcommittee SC 1, Nomenclature and
wormgearing.
This second edition cancels and replaces the first edition (ISO 4468:1982), which has been technically revised.
iv © ISO 2009 – All rights reserved
---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 4468:2009(E)
Gear hobs — Accuracy requirements
1 Scope
This International Standard specifies requirements for the accuracy of general-purpose hobs of 0,5 module to
40 module.
These hobs are intended for producing gears which conform to ISO 53 and ISO 54.
This International Standard applies to hobs for spur and helical gears. It applies to solid (monobloc) and
inserted blade hobs.
The elemental features of hobs are graded according to accuracy, as follows:
⎯ Grade 4A;
⎯ Grade 3A;
⎯ Grade 2A:
⎯ Grade A;
⎯ Grade B;
⎯ Grade C;
⎯ Grade D.
Grade 4A is the highest order of precision.
In addition to the elemental tests for hobs, this International Standard gives permitted tolerances for composite
tests that are taken along the cutting edges on the line of action. The two groups of tests are not equivalent
and one shall choose between one or the other. If there was no previous agreement, the hob is regarded as
belonging to the precision class specified if it satisfies one or the other of the two methods of inspection.
NOTE The tolerances in this International Standard were determined for gear hobs whose dimensions conform to
ISO 2490, but with certain precautions they can be applied to hobs not specified in this International Standard.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 53, Cylindrical gears for general and heavy engineering — Standard basic rack tooth profile
ISO 54, Cylindrical gears for general engineering and for heavy engineering — Modules
© ISO 2009 – All rights reserved 1
---------------------- Page: 5 ----------------------
ISO 4468:2009(E)
ISO 286-2, ISO system of limits and fits — Part 2: Tables of standard tolerance grades and limit deviations for
holes and shafts
ISO 1122-1, Vocabulary of gear terms — Part 1: Definitions related to geometry
ISO 2490, Solid (monobloc) gear hobs with tenon drive or axial keyway, 0,5 to 40 module — Nominal
dimensions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1122-1 and the following apply.
3.1
radial runout of hub diameter
total deviation in radial distance of the hub periphery from the axis
3.2
axial runout of hub face
total axial deviation of the hub face from a true plane of rotation
3.3
radial runout of tips of teeth
total deviation in the radial distance from the axis to the tips of the hob teeth
3.4
straightness and radial alignment over cutting depth
angular relationship between the tooth face and a radial line intersecting the tooth face at the hob outside
diameter, measured in a plane perpendicular to the axis
3.5
adjacent spacing of cutting face of gashes
maximum deviation between any two consecutive cutting face measurements
3.6
total spacing of cutting face of gashes
maximum deviation between any two cutting face measurements
3.7
gash lead deviation per 100 mm
maximum deviation as the probe contacts the tooth faces within axial region of the gash
NOTE Allowable values for deviations are given per 100 mm of cutting face width.
3.8
tooth profile deviation
maximum deviation of that portion of the hob tooth that generates an unmodified involute profile
3.8.1
tooth profile deviation when line of action test is used
maximum deviation of that portion of the hob tooth that generates an unmodified involute profile when the line
of action test is used
NOTE Test 8A is used for tooth profile deviation when the line of action test is used.
2 © ISO 2009 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 4468:2009(E)
3.9
tooth thickness
normal tooth thickness difference of actual and reference datum at the reference cylinder
NOTE Negative only.
3.9.1
addendum
difference of addendum values related to designed normal tooth thickness observed during testing
NOTE Positive only. Test 9A is used for addendum.
3.9.2
tooth thickness difference along one gash
difference between maximum and minimum nominal tooth thickness along one gash at the reference cylinder
NOTE Test 9B is used for tooth thickness difference along one gash. This test is only valid for quality Grades 4A, 3A
and 2A.
3.10
lead deviation on adjacent teeth
maximum lead deviation between any two consecutive teeth
3.11
lead deviation in one axial pitch
maximum deviation between any two teeth within any group of consecutive teeth contained in one axial pitch;
the number of teeth in one axial pitch is the number of teeth encountered by the measurement probe as it
moves parallel to the reference axis during lead testing for a distance of one axial pitch of the hob
NOTE The number of teeth is determined by the number of gashes, the number of threads and, in the case of helical
gash hobs, the gash lead.
3.11.1
lead deviation in one axial pitch when line of action test is used
maximum deviation between any two teeth within any group of consecutive teeth contained in one axial pitch
when the line of action test is used
NOTE Test 11A is used for lead deviation in one axial pitch when the line of action test is used.
3.12
lead deviation in three axial pitches
maximum lead deviation between any two teeth contained in three axial pitches; the number of teeth in three
axial pitches is that number of teeth encountered by the measurement probe as it moves parallel to the
reference axis during lead testing for a distance of three axial pitches of the hob
NOTE The number of teeth is determined by the number of gashes, the number of threads and, in the case of helical
gash hobs, the gash lead.
3.12.1
lead deviation in three axial pitches when line of action test is used
maximum lead deviation between any two teeth contained in three axial pitches when the line of action test is
used
NOTE Test 12A is used for lead deviation in three axial pitches when the line of action test is used.
© ISO 2009 – All rights reserved 3
---------------------- Page: 7 ----------------------
ISO 4468:2009(E)
3.13
adjacent deviation along line of action
maximum deviation between any two consecutive teeth of a given line of action test
NOTE 1 Adjacent hob line of action allowable deviation can be applied to adjacent line of action test results in those
cases where the hob has been specified to be manufactured with involute helicoid geometry.
NOTE 2 Adjacent deviation along the line of action is measured at the cutting edge.
3.14
total deviation along line of action
total maximum deviation between any two teeth of a given line of action test
NOTE 1 Total hob line of action allowable deviation can be applied to total line of action test results in those cases
where the hob has been specified to be manufactured with involute helicoid geometry.
NOTE 2 Total deviation along the line of action is measured at the cutting edge.
3.15
axial pitch deviation from thread to thread
maximum axial pitch deviation between any two consecutive teeth contained within two gashes
NOTE 1 For an odd number of threads, the angle between the gashes is approximately 90°. For an even number of
threads, it is approximately 120°.
NOTE 2 The minimum requirement is to inspect the number of axial pitches equal to the number of threads.
3.16
axial pitch deviation in any three axial pitches over all threads
maximum axial pitch deviation over any three adjacent teeth contained within two gashes
NOTE 1 For an odd number of threads, the angle between the gashes is approximately 90°. For an even number of
threads, it is approximately 120°.
NOTE 2 The minimum requirement is to inspect the number of axial pitches equal to the number of threads.
4 Accuracy requirements
Hobs shall conform to the requirements of Tables 2 and 4, as appropriate.
When prior agreement between the hob manufacturer and purchaser specifies measurement of hobs, the
manufacturer should select:
⎯ the measurement method to be used from among the applicable methods described in this International
Standard and summarized in Table 1;
⎯ the piece of measurement equipment to be used by the selected measurement method, provided it is in
proper calibration;
⎯ the individual teeth to be measured, as long as they are approximately equally spaced.
No particular method of measurement or documentation is considered mandatory. When applications require
measurements beyond those recommended in this International Standard, it is recommended to negotiate
special measurement methods prior to manufacturing the hob.
4 © ISO 2009 – All rights reserved
---------------------- Page: 8 ----------------------
ISO 4468:2009(E)
Table 1 — Reference for measurement methods
a
Test Test number
Test description
method
b
Elemental test Composite test
definition
3.1 Radial runout of hub diameter 1 1
3.2 Axial runout of hub face 2 2
3.3 Radial runout of tips of teeth 3 3
3.4 Straightness and radial alignment over cutting depth 4 4
3.5 Adjacent spacing of cutting face of gashes 5 5
3.6 Total spacing of cutting face of gashes 6 6
3.7 Gash lead deviation per 100 mm 7 7
3.8 Tooth profile deviation 8 8A
3.9 Tooth thickness 9 or 9A and 9B 9 or 9A and 9B
3.10 Lead deviation on adjacent teeth 10 10
3.11 Lead deviation in one axial pitch 11 11A
3.12 Lead deviation in three axial pitches 12 12A
c
3.13 Adjacent deviation along line of action (measured at the cutting edge) — 13
c
3.14 Total deviation along line of action (measured at the cutting edge) — 14
3.15 Axial pitch deviation from thread to thread 15 15
3.16 Axial pitch deviation in any three axial pitches over all threads 16 16
a
See Clause 5.
b
Select the composite test when the line of action test is used.
c
Test does not apply to the elemental method.
5 Derivation of allowable values
5.1 General
Test 7 does not conform to a datum value and is not among the statements in Clause 5 concerning grade
relationships.
With the exception of Test 7, the datum from which all the values in Table 6 are derived is the value of 45 µm
Test 14 Grade A modules 16 to 25.
5.2 Tests 1-7
For tests 1 to 7, use Equation (1):
Calculated value = 45 K K K (1)
e m g
K is not used.
t
© ISO 2009 – All rights reserved 5
---------------------- Page: 9 ----------------------
ISO 4468:2009(E)
5.3 Tests 9, 11, 11A, 12, 12A
For tests 9, 11, 11A, 12, 12A, use Equation (2):
Calculated value = 45 K K K K (2)
e m g t
where
K is the ratio for test element (see Table 3);
e
K is the ratio for division of module (see Table 4);
m
K is the ratio for grade (see Table 3);
g
K is the ratio for number of threads (see Table 5).
t
5.4 Test 9B
Test 9B is only valid for quality Grades 4A, 3A and 2A.
5.5 Tests 8, 8A, 9B, 10, 13, 14, 15 and 16
Tests 8, 8A, 9B, 10, 13, 14, 15 and 16 are only valid for the following:
a) 1-thread, all Module ranges;
b) 2-threads, Module range 0,5 u m u 16;
c) 3- and 4-threads, Module range 0,5 u m u 6;
d) 5-, 6- and 7-threads, Module range 0,5 u m u 3,5.
The value of the allowable deviations has been rounded to the nearest whole value after calculation. The
minimum value of allowable deviations is 2 µm.
Standard bores shall be finished straight and parallel within the tolerances given in Table 2 for 75 % of each
bearing length for Grades 4A, 3A, 2A, A and B hobs and 50 % for Grades C and D hobs.
A reference mandrel of nominal bore diameter shall pass through the bore as a check of alignment.
The tolerances on bore diameter are specified in Table 2.
6 © ISO 2009 – All rights reserved
---------------------- Page: 10 ----------------------
ISO 4468:2009(E)
Table 2 — Tolerance on bores
a
Tolerance
Datum diameter
Grade of hob
mm
8 10 13 22 27 32 40 50 60 80
4A H3
3A
H3 H4
2A
A H4 H5
B H5
C
H6
D
a
In accordance with ISO 286-2.
Table 3 — Ratio for test element and grade
Ratio of grade
Ratio of test element
Test
K
g
number
K
e
4A 3A 2A A B C D
1 0,3
1,6 1,6 2,11
2 0,25
3 1,6 3,6 4,75
4 1,25
1,8
0,35 0,5 0,71 2,38
5 1,4
1,8
1
6 2,6
7 No relationship to test 14 1,25 2,31
8 0,5
4 5,28
8A 0,85
2
9 1,5
0,71 0,71 1 2 2,54
9A As by Table 4
9B 0,8 — — — —
10 0,4
11 0,7
11A 0,8
12 1,3
0,35 0,5 0,71
1 2 4 5,28
12A 1,8
13 0,4
14 1
15 0,45
16 0,8
© ISO 2009 – All rights reserved 7
---------------------- Page: 11 ----------------------
ISO 4468:2009(E)
Table 4 — Ratio for division of module
Module range Ratio for Multiplication
module range factor
m K
m
0,5 u m u 1 0,33
1
1 < m u 2 0,33
1,25
2 < m u 3,5 0,41
1,25
3,5 < m u 6,0 0,51
1,25
6,0 < m u 10 0,64
1,25
10 < m u 16 0,8
1,25
16 < m u 25 1
1,32
25 < m u 40 1,32
Table 5 — Ratio for number of threads
Number Ratio for number Multiplication
of threads of threads factor
K
t
1 1
1,25
2 1,25
1,25
3, 4 1,56
1,25
5, 6, 7 1,95
8 © ISO 2009 – All rights reserved
---------------------- Page: 12 ----------------------
ISO 4468:2009(E)
© ISO 2009 – All rights reserved 9
Table 6 — Accuracy requirements
Allowable deviation
Test Pitch range
µm
Element Drawing Object of test
No. module, m
Grade
(See the end of Table 6 for the key to the drawings.) mm 4A 3A 2A A B C D
0,5 u m u 1 2 2 3 4 7 7 9
1 < m u 2 2 2 3 4 7 7 9
2 < m u 3,5 2 3 4 6 9 9 12
3,5 < m u 6,0 2 3 5 7 11 11 15
1 Hub diameter Radial runout
6,0 < m u 10 3 4 6 9 14 14 18
10 < m u 16 4 5 8 11 17 17 23
16 < m u 25 5 7 10 14 22 22 28
25 < m u 40 6 9 13 18 29 29 38
0,5 u m u 1 2 2 3 4 6 6 8
1 < m u 2 2 2 3 4 6 6 8
2 < m u 3,5 2 2 3 5 7 7 10
3,5 < m u 6,0 2 3 4 6 9 9 12
2 Hub face Axial runout
6,0 < m u 10 3 4 5 7 12 12 15
10 < m u 16 3 5 6 9 14 14 19
16 < m u 25 4 6 8 11 18 18 24
25 < m u 40 5 7 11 15 24 24 31
0,5 u m u 1 8 12 17 24 43 86 113
1 < m u 2 8 12 17 24 43 86 113
2 < m u 3,5 10 15 21 30 53 106 140
3,5 < m u 6,0 13 18 26 37 66 132 174
Radial runout of
3 Outside diameter
tips of teeth
6,0 < m u 10 16 23 33 46 83 166 219
10 < m u 16 20 29 41 58 104 207 274
16 < m u 25 25 36 51 72 130 259 342
25 < m u 40 33 48 67 95 171 342 451
---------------------- Page: 13 ----------------------
ISO 4468:2009(E)
10 © ISO 2009 – All rights reserved
Table 6 — Accuracy requirements (continued)
Allowable deviation
Test Pitch range
µm
Element Drawing Obje
...
SLOVENSKI STANDARD
SIST ISO 4468:2009
01-december-2009
1DGRPHãþD
SIST ISO 4468:1998
3ROåDVWDIUH]DOD=DKWHYHSRWRþQRVWL
Gear hobs - Accuracy requirements
Fraises-mères - Exigences d'exactitude
Ta slovenski standard je istoveten z: ISO 4468:2009
ICS:
21.200 Gonila Gears
SIST ISO 4468:2009 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
---------------------- Page: 1 ----------------------
SIST ISO 4468:2009
---------------------- Page: 2 ----------------------
SIST ISO 4468:2009
INTERNATIONAL ISO
STANDARD 4468
Second edition
2009-06-01
Gear hobs — Accuracy requirements
Fraises-mères — Exigences d'exactitude
Reference number
ISO 4468:2009(E)
©
ISO 2009
---------------------- Page: 3 ----------------------
SIST ISO 4468:2009
ISO 4468:2009(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.
COPYRIGHT PROTECTED DOCUMENT
© ISO 2009
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2009 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 4468:2009
ISO 4468:2009(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 2
4 Accuracy requirements. 4
5 Derivation of allowable values . 5
5.1 General. 5
5.2 Tests 1-7 . 5
5.3 Tests 9, 11, 11A, 12, 12A . 6
5.4 Test 9B . 6
5.5 Tests 8, 8A, 9B, 10, 13, 14, 15 and 16. 6
Bibliography . 32
© ISO 2009 – All rights reserved iii
---------------------- Page: 5 ----------------------
SIST ISO 4468:2009
ISO 4468:2009(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. 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, 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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 4468 was prepared by Technical Committee ISO/TC 60, Gears, Subcommittee SC 1, Nomenclature and
wormgearing.
This second edition cancels and replaces the first edition (ISO 4468:1982), which has been technically revised.
iv © ISO 2009 – All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 4468:2009
INTERNATIONAL STANDARD ISO 4468:2009(E)
Gear hobs — Accuracy requirements
1 Scope
This International Standard specifies requirements for the accuracy of general-purpose hobs of 0,5 module to
40 module.
These hobs are intended for producing gears which conform to ISO 53 and ISO 54.
This International Standard applies to hobs for spur and helical gears. It applies to solid (monobloc) and
inserted blade hobs.
The elemental features of hobs are graded according to accuracy, as follows:
⎯ Grade 4A;
⎯ Grade 3A;
⎯ Grade 2A:
⎯ Grade A;
⎯ Grade B;
⎯ Grade C;
⎯ Grade D.
Grade 4A is the highest order of precision.
In addition to the elemental tests for hobs, this International Standard gives permitted tolerances for composite
tests that are taken along the cutting edges on the line of action. The two groups of tests are not equivalent
and one shall choose between one or the other. If there was no previous agreement, the hob is regarded as
belonging to the precision class specified if it satisfies one or the other of the two methods of inspection.
NOTE The tolerances in this International Standard were determined for gear hobs whose dimensions conform to
ISO 2490, but with certain precautions they can be applied to hobs not specified in this International Standard.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 53, Cylindrical gears for general and heavy engineering — Standard basic rack tooth profile
ISO 54, Cylindrical gears for general engineering and for heavy engineering — Modules
© ISO 2009 – All rights reserved 1
---------------------- Page: 7 ----------------------
SIST ISO 4468:2009
ISO 4468:2009(E)
ISO 286-2, ISO system of limits and fits — Part 2: Tables of standard tolerance grades and limit deviations for
holes and shafts
ISO 1122-1, Vocabulary of gear terms — Part 1: Definitions related to geometry
ISO 2490, Solid (monobloc) gear hobs with tenon drive or axial keyway, 0,5 to 40 module — Nominal
dimensions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1122-1 and the following apply.
3.1
radial runout of hub diameter
total deviation in radial distance of the hub periphery from the axis
3.2
axial runout of hub face
total axial deviation of the hub face from a true plane of rotation
3.3
radial runout of tips of teeth
total deviation in the radial distance from the axis to the tips of the hob teeth
3.4
straightness and radial alignment over cutting depth
angular relationship between the tooth face and a radial line intersecting the tooth face at the hob outside
diameter, measured in a plane perpendicular to the axis
3.5
adjacent spacing of cutting face of gashes
maximum deviation between any two consecutive cutting face measurements
3.6
total spacing of cutting face of gashes
maximum deviation between any two cutting face measurements
3.7
gash lead deviation per 100 mm
maximum deviation as the probe contacts the tooth faces within axial region of the gash
NOTE Allowable values for deviations are given per 100 mm of cutting face width.
3.8
tooth profile deviation
maximum deviation of that portion of the hob tooth that generates an unmodified involute profile
3.8.1
tooth profile deviation when line of action test is used
maximum deviation of that portion of the hob tooth that generates an unmodified involute profile when the line
of action test is used
NOTE Test 8A is used for tooth profile deviation when the line of action test is used.
2 © ISO 2009 – All rights reserved
---------------------- Page: 8 ----------------------
SIST ISO 4468:2009
ISO 4468:2009(E)
3.9
tooth thickness
normal tooth thickness difference of actual and reference datum at the reference cylinder
NOTE Negative only.
3.9.1
addendum
difference of addendum values related to designed normal tooth thickness observed during testing
NOTE Positive only. Test 9A is used for addendum.
3.9.2
tooth thickness difference along one gash
difference between maximum and minimum nominal tooth thickness along one gash at the reference cylinder
NOTE Test 9B is used for tooth thickness difference along one gash. This test is only valid for quality Grades 4A, 3A
and 2A.
3.10
lead deviation on adjacent teeth
maximum lead deviation between any two consecutive teeth
3.11
lead deviation in one axial pitch
maximum deviation between any two teeth within any group of consecutive teeth contained in one axial pitch;
the number of teeth in one axial pitch is the number of teeth encountered by the measurement probe as it
moves parallel to the reference axis during lead testing for a distance of one axial pitch of the hob
NOTE The number of teeth is determined by the number of gashes, the number of threads and, in the case of helical
gash hobs, the gash lead.
3.11.1
lead deviation in one axial pitch when line of action test is used
maximum deviation between any two teeth within any group of consecutive teeth contained in one axial pitch
when the line of action test is used
NOTE Test 11A is used for lead deviation in one axial pitch when the line of action test is used.
3.12
lead deviation in three axial pitches
maximum lead deviation between any two teeth contained in three axial pitches; the number of teeth in three
axial pitches is that number of teeth encountered by the measurement probe as it moves parallel to the
reference axis during lead testing for a distance of three axial pitches of the hob
NOTE The number of teeth is determined by the number of gashes, the number of threads and, in the case of helical
gash hobs, the gash lead.
3.12.1
lead deviation in three axial pitches when line of action test is used
maximum lead deviation between any two teeth contained in three axial pitches when the line of action test is
used
NOTE Test 12A is used for lead deviation in three axial pitches when the line of action test is used.
© ISO 2009 – All rights reserved 3
---------------------- Page: 9 ----------------------
SIST ISO 4468:2009
ISO 4468:2009(E)
3.13
adjacent deviation along line of action
maximum deviation between any two consecutive teeth of a given line of action test
NOTE 1 Adjacent hob line of action allowable deviation can be applied to adjacent line of action test results in those
cases where the hob has been specified to be manufactured with involute helicoid geometry.
NOTE 2 Adjacent deviation along the line of action is measured at the cutting edge.
3.14
total deviation along line of action
total maximum deviation between any two teeth of a given line of action test
NOTE 1 Total hob line of action allowable deviation can be applied to total line of action test results in those cases
where the hob has been specified to be manufactured with involute helicoid geometry.
NOTE 2 Total deviation along the line of action is measured at the cutting edge.
3.15
axial pitch deviation from thread to thread
maximum axial pitch deviation between any two consecutive teeth contained within two gashes
NOTE 1 For an odd number of threads, the angle between the gashes is approximately 90°. For an even number of
threads, it is approximately 120°.
NOTE 2 The minimum requirement is to inspect the number of axial pitches equal to the number of threads.
3.16
axial pitch deviation in any three axial pitches over all threads
maximum axial pitch deviation over any three adjacent teeth contained within two gashes
NOTE 1 For an odd number of threads, the angle between the gashes is approximately 90°. For an even number of
threads, it is approximately 120°.
NOTE 2 The minimum requirement is to inspect the number of axial pitches equal to the number of threads.
4 Accuracy requirements
Hobs shall conform to the requirements of Tables 2 and 4, as appropriate.
When prior agreement between the hob manufacturer and purchaser specifies measurement of hobs, the
manufacturer should select:
⎯ the measurement method to be used from among the applicable methods described in this International
Standard and summarized in Table 1;
⎯ the piece of measurement equipment to be used by the selected measurement method, provided it is in
proper calibration;
⎯ the individual teeth to be measured, as long as they are approximately equally spaced.
No particular method of measurement or documentation is considered mandatory. When applications require
measurements beyond those recommended in this International Standard, it is recommended to negotiate
special measurement methods prior to manufacturing the hob.
4 © ISO 2009 – All rights reserved
---------------------- Page: 10 ----------------------
SIST ISO 4468:2009
ISO 4468:2009(E)
Table 1 — Reference for measurement methods
a
Test Test number
Test description
method
b
Elemental test Composite test
definition
3.1 Radial runout of hub diameter 1 1
3.2 Axial runout of hub face 2 2
3.3 Radial runout of tips of teeth 3 3
3.4 Straightness and radial alignment over cutting depth 4 4
3.5 Adjacent spacing of cutting face of gashes 5 5
3.6 Total spacing of cutting face of gashes 6 6
3.7 Gash lead deviation per 100 mm 7 7
3.8 Tooth profile deviation 8 8A
3.9 Tooth thickness 9 or 9A and 9B 9 or 9A and 9B
3.10 Lead deviation on adjacent teeth 10 10
3.11 Lead deviation in one axial pitch 11 11A
3.12 Lead deviation in three axial pitches 12 12A
c
3.13 Adjacent deviation along line of action (measured at the cutting edge) — 13
c
3.14 Total deviation along line of action (measured at the cutting edge) — 14
3.15 Axial pitch deviation from thread to thread 15 15
3.16 Axial pitch deviation in any three axial pitches over all threads 16 16
a
See Clause 5.
b
Select the composite test when the line of action test is used.
c
Test does not apply to the elemental method.
5 Derivation of allowable values
5.1 General
Test 7 does not conform to a datum value and is not among the statements in Clause 5 concerning grade
relationships.
With the exception of Test 7, the datum from which all the values in Table 6 are derived is the value of 45 µm
Test 14 Grade A modules 16 to 25.
5.2 Tests 1-7
For tests 1 to 7, use Equation (1):
Calculated value = 45 K K K (1)
e m g
K is not used.
t
© ISO 2009 – All rights reserved 5
---------------------- Page: 11 ----------------------
SIST ISO 4468:2009
ISO 4468:2009(E)
5.3 Tests 9, 11, 11A, 12, 12A
For tests 9, 11, 11A, 12, 12A, use Equation (2):
Calculated value = 45 K K K K (2)
e m g t
where
K is the ratio for test element (see Table 3);
e
K is the ratio for division of module (see Table 4);
m
K is the ratio for grade (see Table 3);
g
K is the ratio for number of threads (see Table 5).
t
5.4 Test 9B
Test 9B is only valid for quality Grades 4A, 3A and 2A.
5.5 Tests 8, 8A, 9B, 10, 13, 14, 15 and 16
Tests 8, 8A, 9B, 10, 13, 14, 15 and 16 are only valid for the following:
a) 1-thread, all Module ranges;
b) 2-threads, Module range 0,5 u m u 16;
c) 3- and 4-threads, Module range 0,5 u m u 6;
d) 5-, 6- and 7-threads, Module range 0,5 u m u 3,5.
The value of the allowable deviations has been rounded to the nearest whole value after calculation. The
minimum value of allowable deviations is 2 µm.
Standard bores shall be finished straight and parallel within the tolerances given in Table 2 for 75 % of each
bearing length for Grades 4A, 3A, 2A, A and B hobs and 50 % for Grades C and D hobs.
A reference mandrel of nominal bore diameter shall pass through the bore as a check of alignment.
The tolerances on bore diameter are specified in Table 2.
6 © ISO 2009 – All rights reserved
---------------------- Page: 12 ----------------------
SIST ISO 4468:2009
ISO 4468:2009(E)
Table 2 — Tolerance on bores
a
Tolerance
Datum diameter
Grade of hob
mm
8 10 13 22 27 32 40 50 60 80
4A H3
3A
H3 H4
2A
A H4 H5
B H5
C
H6
D
a
In accordance with ISO 286-2.
Table 3 — Ratio for test element and grade
Ratio of grade
Ratio of test element
Test
K
g
number
K
e
4A 3A 2A A B C D
1 0,3
1,6 1,6 2,11
2 0,25
3 1,6 3,6 4,75
4 1,25
1,8
0,35 0,5 0,71 2,38
5 1,4
1,8
1
6 2,6
7 No relationship to test 14 1,25 2,31
8 0,5
4 5,28
8A 0,85
2
9 1,5
0,71 0,71 1 2 2,54
9A As by Table 4
9B 0,8 — — — —
10 0,4
11 0,7
11A 0,8
12 1,3
0,35 0,5 0,71
1 2 4 5,28
12A 1,8
13 0,4
14 1
15 0,45
16 0,8
© ISO 2009 – All rights reserved 7
---------------------- Page: 13 ----------------------
SIST ISO 4468:2009
ISO 4468:2009(E)
Table 4 — Ratio for division of module
Module range Ratio for Multiplication
module range factor
m K
m
0,5 u m u 1 0,33
1
1 < m u 2 0,33
1,25
2 < m u 3,5 0,41
1,25
3,5 < m u 6,0 0,51
1,25
6,0 < m u 10 0,64
1,25
10 < m u 16 0,8
1,25
16 < m u 25 1
1,32
25 < m u 40 1,32
Table 5 — Ratio for number of threads
Number Ratio for number Multiplication
of threads of threads factor
K
t
1 1
1,25
2 1,25
1,25
3, 4 1,56
1,25
5, 6, 7 1,95
8 © ISO 2009 – All rights reserved
---------------------- Page: 14 ----------------------
SIST ISO 4468:2009
ISO 4468:2009(E)
© ISO 2009 – All rights reserved 9
Table 6 — Accuracy requirements
Allowable deviation
Test Pitch range
µm
Element Drawing Object of test
No. module, m
Grade
(See the end of Table 6 for the key to the drawings.) mm 4A 3A 2A A B C D
0,5 u m u 1 2 2 3 4 7 7 9
1 < m u 2 2 2 3 4 7 7 9
2 < m u 3,5 2 3 4 6 9 9 12
3,5 < m u 6,0 2 3 5 7 11 11 15
1 Hub diameter Radial runout
6,0 < m u 10 3 4 6 9 14 14 18
10 < m u 16 4 5 8 11 17 17 23
16 < m u 25 5 7 10 14 22 22 28
25 < m u 40 6 9 13 18 29 29 38
0,5 u m u 1 2 2 3 4 6 6 8
1 < m u 2 2 2 3 4 6 6 8
2 < m u 3,5 2 2 3 5 7 7 10
3,5 < m u 6,0 2 3 4 6 9 9 12
2 Hub face Axial runout
6,0 < m u 10 3 4 5 7 12 12 15
10 < m u 16 3 5 6 9 14 14 19
16 < m u 25 4 6 8 11 18 18 24
25 < m u 40 5 7 11 15 24 24 31
0,5 u m u 1 8 12 17 24 43 86 113
1 < m u 2 8 12 17 24 43 86 113
2 < m u 3,5 10 15 21 30 53 106 140
3,5 < m u 6,0 13 18 26 37 66 132 174
Radial runout of
3 Outside diameter
tips of teeth
6,0 < m u 10 16 23 33 46 83 166 219
10 < m u 16 20 29 41 58 104 207 274
16 < m u 25 25 36 51 72 130 259 342
25 < m u 40 33
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.