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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.
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“The Right to Information, The Right to Live”
“Step Out From the Old to the New”
Mazdoor Kisan Shakti Sangathan
Jawaharlal Nehru
IS 2473 (1975): Dimensions for centre holes [PGD 20:
Engineering Standards]
“!ान $ एक न' भारत का +नम-ण”
Satyanarayan Gangaram Pitroda
“Invent a New India Using Knowledge”
“!ान एक ऐसा खजाना > जो कभी च0राया नहB जा सकता ह”
है”
ह
Bhartṛhari—Nītiśatakam
“Knowledge is such a treasure which cannot be stolen”
UDC
Fourth
Reprint NOVEMBER 1991
( IncorPoratinaAmendment No. 1 1
:389-W
621’9-229’335
4s
(R-=-d
: 2413 -
raz
19781
Indian
?
( Reaffirmed 2002 )
Standard
DIMENSIONS FOR CENTRE
( First
Revision
HOLES
)
1
; 1. Scope I
Prescribes dimensions for the,following
three types of centre holes:
Type A - Centre holes without protecting chamfers
Type I3 - Centre holes with protecting chamfers
Type R - Centre holes with radius form
,
2’. Dimensions
, 2’.l Cenfre Holes Without
Protecting
Chamfers,
Type A
I-4
i-a-4
Ail dimensions
in miiiimetres.
D
d
Nominal
at
Nominal
Refetence
_
1’06
(0’5)
( 0’63 )
2
I
I
1’32
I’2
2
I’70
I’5
2’5
____
-__-
1'0
( 1’25
1’0
I
I
2’12
)
I’6
I’9
2’65
2’3
3’35
2’9
3
I
t
~-
,
2’0
4’25
2.5
5’30
3'15
)__
4’6
I
6’70
_~
--_--
X7
_/
--
5’9
9
4.0
8’50
7’4
11
( 5’0 1
10’60
9.2
14
8’3
13’20
II’5
( 8’0 1
17’00
14.8
_
18
22
_ _-.
Note -
Sizes given within
brackets
28
18’4
21’20
10’0
are non-preferred
and shall be avoided
whenever
possible.
*Dimensioin 1 depends upon length I of the centre drill according
to IS : 6708-1972 ‘ Specification
for &Me
drills,
centre drills, be less than the reference value f given
Type A ‘. it shall not, even in the case of drilling with re-sharpened
in the table to ensure that the point of the centre does not touch the bottom of the centre hole.
tparting
off dimension,
if the centre hole is to be removed’from
the finished
workpiece.
I
Adopted
L
27 November
Q July 1932, BIS
1975
I
BUREAU‘
MANAK
OF
INDIAN
BHAVAN, 9 BAHADUR
I
STANDARDS
SHAH ZAFAR MARG
NEW DELHI 1loo02
Gr2
IS : 2473- 191s
2.2 Centre HoIes With Protecting Chamfers, Type B
All dimensions in millimetres.
-
NOIL
NoL
Refefence
at
__
315
2’2
3’5
4
2’7
4’5
5
3’6
56
2’0
53
4’3
6’6
9’5
8
5’4
8’3
3’15
10
6’3
10’0
4’0
12’5
8’6
12’7
10’8
15’6
12.9
20’0
16’4
25’0
20’4
31’0
1'0
-.
(1.25)
__
1’6
.-
18
( 5’0 1
._
13
6’3
-
22’4
(8’0)
__10’0
28
Noto-Sizes
given within brackets are non-preferred and shall be avoided whenever possible.
*Dimension L depends u on length I of the centre drill according to IS : 6709-1972 ’ Specification for centre drills,
Type B ‘. It shall not, even Pnthe case of drllllng with re-sharpened centre drills, be less than the reference value t given
In the table to ensure that the point of the centre does not touch the bottom of the centre hole.
tParting off dimension, If the centre hole is to be removed from the finished workpiece.
2
IS : 2473- 1975
2.3 Centre Holes With Radius Form, Type R
All dimensions in millimetres.
I
No:lnal
D
r
Refetence
Nominal
d
yin
Max
--
.
1’5
8
I
4’0
3’15
4
I
2.9
5’0
4’0
5
I
3’7
6’3
5’0
6
4’6
8’0
6’5
7
5’8
10’0
8’0
9
7’4
12’5
10’0
11
9’2
18’0
125
14
13’2
11’4
20’0
16’0
18
17’0
14’7
25.0
20’0
22
21’2
18’3
31’5
25’0
28
1’9
1’0
2’12
( 1’25 )
2’65
2’3
1’6
3’35
2’0
4’25
2.5
5’3
3’15
8’7
4’0
6’6
( 5’0 1
10’6
-
&3
I
(VO)
10’0
Note -
-1
_
_.
_
.-
--_.-_
9’15
---
I
/I
Sizes given within brackets are non-preferred and shall be avoided whenever possible.
!
*Dimension L depends upon length I of the centre drill according to IS : 8710-1972 ‘ Specification for centre drills,
Type D ‘. It shall not, even in the case of drilling with m-sharpened centre drills, be less than the referencevalue t given
in the table to ensure that the point of the centre does not touch the bottom of the centre hole.
I
TParting off dimension;if.the centre hole is to be removed from the finished workpiece.
2.4 Dimensional
deviations for untoleranced dimensions; Medium class according to IS : 2102-1969
i Allowable
deviations for dimensions without specified tolerances (first revision ) ‘.
2.5 For Inspection
purposes,
2.6 For values
Appendix A.
of suitable
3. Designation
-
a centre
limits
drill which
has not been repround
of workpiece diameters for different
shall
be used.
sizes of centre holes, see
A centre hole of Type A and diameter d = 1’6 mm shall be designated as:
Centre Hole A x 1’6 IS : 2473
3
.
IS : 2473 - 1975
APPENDIX
A
( Clause 2.6)
LIMITS
OF WORKPIECE DIAMETERS FOR DIFFERENT SIZES OF CENTRE HOLES
All dimensions
d
Nominal
.I
Diameter
in millimetres.
Weight of Manufactured
Workpiece, kg, Max
of Workpiece
Over
up to
-
4
0.5
/
-
I
o-8
4
I
1'0
6
IO
-
I
I.6
10
16
-
2’5
16
40
-
4’0
40
60
-
6’3
-
-
1600
10.0
-
-
4000
6
-
I
I
Note -These
values
are for all types of centre holes (Types
EXPLANATORY
A, B and R) and are for information
~__
.~
only.
NOTE
This standard
was originally
issued in the year 1963. The
necessary as the standard on centre drills
IS : 664-1963 has since
splitting the original standard Into the following
three sfandards:
IS :.6708-1972 Specification
for centre
drills,
Type A
IS : 6709-1972 Specification
for centre
drills,
Type 6
IS : 6710-1972 Specification
for centre
drills,
Type D
This revision
of IS : 2473 has also brought
addition,
suitable
limits of workpiece
diameters
included in an appendix far information.
the standard
for different
present
revision
been revised
has become
and published
in line with the IS0 standard
In
sizes of centre holes have been
4
Reprography
Unit,
BIS,
New Delhi,
India
AMENDMENT NO. 2 JANUARY 2008
TO
IS 2473:1975 DIMENSIONS FOR CENTRE HOLES
(First Revision )
(Page 4, ExpIanatoty Note) — Substitute the following for the existing:
‘This standard was originally issued in the year 1963. The present revision has
become necessary as the standard on centre drills IS 664: 1963 has since been
revised and published splitting the original standard into the following three
standards:
IS 6708:1977
Specification
for centre drills, Type A
K 6709:197’7
Specification
for centre drills, Type B
1S6710 :1977
Specification
for centre drills, Type R
This revision of IS 2473 has also brought the standard in line with 1S0 866:
1975, 1S0 2540: 1973, and 1S0 2541 : 1972 for Type A, Type B and Type R
centre l+ioles respectively. In addition, suitable limits of workpiece diameters for
different sizes of centre holes have been included in an appendix
for
information.’
(PG 20)
ReprographyUnit,BIS,New Delhi, India
.
.