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“Invent a New India Using Knowledge”

है”ह”ह

IS 11668 (1985): Technical drawings - Simplifiedrepresentation of centre holes [PGD 24: Drawings]

IS : 11668 - 1985 UDC 744’43 : 621 - 229’335 : 003.62 IS0 6411 - 1982

The reference of ISO’ 6,411 indicated in designation should be read as IS : 11668 - IS0 6411.

Cross References

international Standard Corresponding Indian Standard

IS0 128-l 982 IS : 10714-1983 General ~principles of present- ation on technical drawings ( Identical )

IS0 866.1975 IS : 6708.1977 Specification for centre drills Type A ( first revision ) (Technically equivalent)

IS0 2540-l 972 IS : 67091977 Specification for centre drills Type l3 ( first revision ) ( Technically equivalent )

IS0 2541-l 972 IS : 6710-1977 Specification for centre drills Type R ( first revisiorl ) (Technically Equivalent i

IS0 3098 l-1974 IS : 9609 ( Part 1 )-1983 Lettering on technical drawings: Part 1 English lettering ( firsi revision ) ( Identical )

IS0 6428-l 982 lS : 101641985 Requirements to execute techni- cal drawings for microcopying ( first revision ) ( Identical )

Is1 1 I

I

._C. . ..p_

National Foreword

Indian Standard

TECHNICAL DRAWINGS - SIMPLIFIED REPRESENTATION OF CENTRE HOLES

This Indian Standard is identical with IS0 641 I-1982 ’ Technical drawings - Srmplified ‘epresentation of centre holes ’ issued by the International Organization for Standardization ( IS0 I, was adopted by the Indian Standards Institution on the recommendation of the Drawings Sectional Committee and approvafof the Mechanical Engineering Division Council.

In the adopted standard certain terminology and conventions are not identical with those used II? Indian Standard; attention is especially drawn to the following:

Wherever the words ’ International Standard ’ appear, referring to this standard, they should be read as ’ Indian Standard ‘.

Adopted 1 November 1985 I

@ March 1987, ISI I

Gr 3

._.- .._. --._.-_--^ ._.^_._.._.^_. INDIAN SIANUAi+US INS I I I U I ILJN MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

IS : 11668 - 1985 IS0 6411 - 1982

1 Scope and field of application

This International Standard specifies the simplified represen-

tation of centre holes and their designation. Simplified

representation of centre holes may be used particularly when it

is not necessary to show the exact form and size and where the

designation of standardized centre holes is sufficient for infor-

mation.

IS0 309811, Technical drawings - Lettering - Part 1 : Current& used characters.

IS0 6428, Technical drawings - Requirements for micro-

copying. 1)

3 Indication on drawings 2 References

3.1 Requirements IS0 128, Technical drawings - ~General principles of presen-

tation.

IS0 866, Centre drills for centre holes without protecting

chamfers - Type A.

IS0 2540, Centre drills for centre holes with protecting

chamfers - Type 6.

IS0 2541, Centre drik for centre holes with radius form -

Type R.

1) At present at the stage of draft.

Generally, three different requirements may be defined on

technical drawings for the form and size of centre holes,

namely :

a) centre hole is required on the finished part;

b) centre hole can be accepted on the finished part, but is

not a fundamental requirement;

c) centre hole shall not exist on the finished part.

a

IS :11668-1985 IS0 6411 -1982

3.2 Simplified representation

The symbols representing centre holes and their application to

the end face of a shaft are shown in column 2 of table 1.

3.3 Designation of centre holes

The designation of centre~holes is dependent on the drill and

may be indicated with refarence either to an International Stan-

dard or to any other standard dealing with this subject.

The desrgnation of the centre hole itself consists of

- a reference to this International Standard;

- the letter for the type (I% A or 6);

- the prlot arameter d;

-. the outside countersink centre hole diameter D.

The two values are separated by a solidus.

Example : a centre holet), type B with d = 2.5 mm and

D3 = 8 mm may be indicated on the drawing as :

IS0 8411-B 2,5/8

4 Interpretation of vindication

The relationship between the various designations used to

specify the centre holes, the dimensions represented by the

given designations, and dimensions depending on the centre

drill used are shown in table 2.

Further details specifying the dimensions of the centre hole, to

be indicated preferably on the drawings, are given in annex A

Table 1 - Representation and designation of centre holes on drawings Dimensions in millrmetres

Requirement Repreeentatian Designation

Centre hole is required on the

rinished part

Centre hole may remain on the

finished part

Centre hde shatl not exisf on the

finished part .___- SO 6411-B2.51'1 3

II For the machining of such a centre hole, a drill with d = 2,5 and d, = 10 according to IS0 2540 is used.

3

IS :I1668 -1985 IS0 6411 - 1982

Type of centre hole

R with radius form

entre drill according to

IS0 2541)

A without protecting

chamfer

centre drill according tl

IS0 866)

6 with protecting chamft

(centre drill according

IS0 2540)

I Table 2 - interpretation of the designation

Dimensions in milllmetres

D_esignation (examples) Interpretation of the designation

IS0 6411-R 3.lV6.7

_~. 6411-A 418.5

_~. 6411- 82,5/8

l For dimension I, see annex A

i _

d = 3.15 D,= 6.7

L L-4 t* I**

d=4 D2= 8.5

c/=2,5 4=8

l * Dimension I depends on the length of the centre drill. It should not he less than i

4

IS : 11668 - 1985 IS0 6411 - 1982

Annex A

Dimensions for centre holes type R, A and B

The dimensions which are necessary to specify a centre hole are shown in table 3

Table 3 - Dimensions of preferred centre holes

d nom.

10,5)

(0,631

(0.8)

1.0

(1.25)

1.6

2,o

2.5

3.15

4.0

(5 0)

6.3

(8.01

10.0

R - according to IS0 2641

DI nom.

2.12

2.65

3.35

4.25

5.3

6.7

8.5

10.6

13.2

17.0

21.2

Tvw A

according to IS0 866 B

accordtnq to IS0 2540

4

nom.

1.06

1.32

1.70

2.12

2~65

3.35

4,25

5.30

6,70

8.50

10.60

13.20

17,00

21.20

t

1

I

ref

0.5

06

0.7

0.9

l,l

1.4

1.8

2.2

2.8

3.5

4.4

55

7.0

a.7

r* “0”)

3 15

4

5

6.3

8

10

12.5

16

18

224

28

i ref

I

0.9

1.1 14

1.8

2.2

2.8

35

NOTE - Sizes in brackets should be avoided whenever possible.

IS : 11668 - 1985 IS0 6411 - 1982

.

Proportions and dimensions af symbols

Annex B

In order to harmonize the sizes of the symbols specified in thiq

International Standard with those of the other inscriptions on

the drawing (dimensions, tolerances, etc.) the following rules

shall he ohserved.

B.l General requirements

B.l.1 The symbols shown in the table shall he inscribed with

a line thickness (d’ ) equal to 1 /lO of the height (h) of the letter-

ing used for the dimensions in the relevant drawing.

B.1.2 The numerals and capital letters used for the additional

specifications of centre holes shall be inscribed with the same

line thickness (~‘1, height (h) and type of lettering as us&d for

the dimensions in the relevant drawing, and in accordance with

IS0 309811.

B.1.3 The minimum spacing hetween adjacent lines shall be

in accordance with IS0 128 or IS0 6428.

It is recommended that this spacing he not less than 0.7 mm.

B.2 Proportions

The symhol and its complements shown in area a (see 8.3)

shall he drawn in accordance with the figure.

B.3 Dimensions

The range of sizes to he used for the symbols and additional

indications is given in tahle 4.

Table 4 - Dimensions, in millimetres

Line thickness for outlines of an item Ih) 0.5 0.7 1 1.4 2 2.8

Height of_numerals and capital letters (h) 3.5 5 7 10 14 20

- Line thickness for symbols (d’ ) 0.35 0.5 0.7 1 1.4 2

______~_ Line thickness for lettering (d) see 8.1.2

Height H1 5 7 10 14 20 28

Figure

Reprography Unit, ISI, New Delhi, India

6