review of indian standards

1

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

A COURSE ON GEOMETRICAL DIMENSIONING AND TOLERANCING

2

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

REVIEW OF INDIAN STANDARS

3

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

REVIEW OF INDIAN STANDARDS RELATED TO DRAWING PRCTICE / DESIGN

IS 696-1972 ‘Code of practice for general engineering drawing‘ was issued indicating the various general recommendations like sheet sizes, scales, dimensioning &

tolerancing, method of projection, surface roughness, welding symbols etc.

ISO has published number of standards on various subjects covered in IS:696-1972.

BIS has subsequently adopted all these standards and IS:696-1972 was made obsolete.

4

REVIEW OF INDIAN STANDARDS..Contd.

IS:9609 – English lettering for technical drawings. IS:10711 – Sizes of drawing sheets. IS:10712 – Presentation of item references on technical drawings. IS:10713 – Scales for use in technical drawings. IS:10714 – General principles of presentation on technical drawings. IS:10715 – Presentation of threaded parts on technical drawings. IS:10716 – Rules for representation of springs on technical drawings. IS:10717 – Conventional representation of gears on technical

drawings. IS:10718 – Method of dimensioning and tolerancing cones on technical

drawings. IS:10719 – Method of indicating surface texture on technical

drawings. IS 10720 – Technical drawings for structural metal works. IS:11663 – Conventional representation of common features and

materials on technical drawings. IS:11669 – General principles of dimensioning on technical drawings.

5

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

IS:919 (2 parts) – ISO system of limits and fits.IS:2102(2 parts) – General tolerances.IS:2709 – Guide for selection of fits.IS:8000(4 parts) – Tolerances of form and

position for engineering drawings.

IS:3073 – Assessment of surface roughness.

IS:4218 (6 parts) – ISO Metric screw threads

REVIEW OF INDIAN STANDARDS..Contd.

6

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

RECOMMENDED SCALES

Full Scale Reduced Scale Enlarged Scale 1:1 1:2 10:1

1:2.5 5:1 1:5 2:1 1:10 1:20 1:50 1:100 1:200

7

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

The symbol is indicated on the drawing clearly in the title block.

Symbol for first angle projection

Symbol for third angle projection

Projections

8

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Dimensions shall be given from visible out lines rather than from hidden lines.

Dimensioning on Engg. Drgs.

9

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Dimensioning on Engg. Drgs.

It is preferable to give dimensions from a base line or a centre line of a hole or a cylindrical part.

10

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Dimensioning to a center line shall be avoided except when the center line passes through the centre of a hole or a cylindrical part.

Dimensioning .... Contd..

11

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Dimension lines and projection lines are drawn as continuous thin lines.

Projection lines should extend slightly beyond the dimension line.

Dimensioning .... Contd..

12

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Dimensioning .... Contd..

Construction and intersecting projection lines should extend slightly beyond the point of intersection.

13

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Leaders which touch the lines shall not be normally inclined less than 30o angle.

Should not be parallel to the adjacent dimension or projection line.

Dimensioning .... Contd..

14

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Dimensioning .... Contd..

Use of common leader should be avoided.

15

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Dimensioning Arrows

16

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Inscription of dimensions

17

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

The diameter symbol ‘’ is used, before a dimension to indicate the diameter.

Addition of letters and symbols

18

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Addition of letters and symbols

The letter ‘R’ is used, before a dimension to indicate a radius.

19

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Addition of letters and symbols

The letter ‘SQ’ is used, before a dimension to indicate a square.

20

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Addition of letters and symbols

The letter ‘HEX’ is used, to indicate a hexagon before across dimension.

21

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Addition of letters and symbols

The word ‘SPHERE’ is used, to indicate a spherical surface before the radius or diameter dimension.

22

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Special indications

To indicate a surface or a surface zone to give an additional treatment which shall be applied within limits to be specified on the drawing.

23

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Arrangement of dimensions

Chain dimensioning

24

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Arrangement of dimensions

Parallel dimensioning

25

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Arrangement of dimensions

Combined dimensioning

26

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Dimensioning by coordinates

27

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Dimensioning by coordinates…contd.

28

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Superimposed running dimensioning

29

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Equidistant features

30

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Equal dimensions

31

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Assembled parts

32

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

The tolerance value restricted to the specified length.

33

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

ANGULAR DIMENSIONS

34

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

DIMENSIONING OF KEY WAYS & TAPERS

35

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

36

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

37

TOLERANCES FOR LINEAR AND ANGULAR DIMENSIONS WITHOUT INDIVIDUAL TOLERANCE INDICATIONS

38

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

INDICATIONS ON THE DRAWINGS

GENERAL TOLERANCES FOR LINEAR DIMENSIONS ARE AS FOLLOWS.

Designation Description

f fine

m medium

c course

v very course

39

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

INDICATIONS ON THE DRAWINGS

General tolerances about the untoleranced dimensions to be given near the title block in the drawing.Ex: Un toleranced dimensions as per : IS – 2102 – medium. Permissible deviations for linear dimensions

Permissible deviations for basic size rangeDesignati

onDescriptio

n

0.5 – 3 3 – 6 6 - 30 30 – 120

120 -400

400 -1000

1000 -2000

2000 -4000

f fine ± 0.05

±0.05

±0.1 ±0.15 ±0.2 ±0.3 ±0.5 -

m mediu

m

± 0.1 ±0.1 ±0.2 ±0.3 ±0.5 ±0.8 ±1.2 ±2

c course ± 0.2 ±0.3 ±0.5 ±0.8 ±1.2 ±2 ±3 ±4

v very course

- ±0.5 ±1 ±1.5 ±2.5 ±4 ±6 ±8For nominal sizes below 0.5mm, the deviations shall be indicated adjacent to the relevant nominal size (s)

40

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

GENERAL TOLERANCES FOR RADII AND CHAMFER HEIGHTS

Permissible deviations for basic size range

Designation

Description

0.5 - 3 Over 3 – 6 Over 6

f fine

± 0.2 ± 0.5 ± 1m medium

c course

± 0.4 ± 1 ± 2v very course

For nominal sizes below 0.5mm, the deviations shall be indicated adjacent to the relevant nominal size (s)

41

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

ANGULAR DIMENSIONS

Permissible deviations for ranges of lengths, in mm, of the shorter side of the angle concerned

Designation

Description

Upto 10 Over 10-50

Over 50-120

Over 120-400

Over 400

f fine

±1o ±0o30’

±0o20’ ±0o10’

±0o5’m medium

c course ±1o30’

±1o ±0o30’ ±0o15’

±0o10’

v very course ±3o ±2o ±1o ±0o30’

±0o20’

Shorter side of the angle concerned

42

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

TOLERANCE DISPOSITION CHART

43

THE INSTITUTE FOR ENHANCEMENT OF TECHNOLOGY

Accuracy expected of manufacturing process