Engineering graphics instructions

Engineering Graphics

Presents BY

A.S.VAGH

M.Tech (IPED) , B.E. Mechanical, PGDIM

E-mail Id: asvagh@india.com

Lines

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Viewing-plane line

Extension lineDimension Line Center Line

Hidden Line

Break Line

Cutting-plane Line

Visible Line

Center Line (of motion)

Leader

VIEW B-BSECTION A-A

Section Line

Phantom Line

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Horizontal Lines

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Vertical Lines

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Inclined Lines

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Parallel Lines

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Perpendicular Lines

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Circles and Arcs

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Drawing a circle of a given

diameter with a compass

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Use of the French Curve

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Guidelines for Lettering

For uniformity, all letters should be the same height,

proportion and inclination. A necessary tactic for

maintaining uniformity is the use of guidelines.

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Guidelines for Lettering

Ascender is the part of the lowercase letter that extends

above the body of the letter.

Descender is the part of the lowercase letters that

extends below the body letter.

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Lettering

Writing titles, dimensions, notes and other important

particular on a drawing is called lettering.

Lettering should be done properly in clear,

understandable & uniform style.

It should be in plain & simple style so that it could be

done free hand & speedily.

Note: Use of drawing instruments in lettering takes

considerable time and hence, it should be avoided

efficiency in the art of lettering can be achieved by careful

& continuous practice.

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Lettering

The size of letter is specified by its height.

Generally the ratio of height to width for most of the

capital letters are taken as 6:5 and for most of the

lower case letters are taken as 4:4.

Main letter are generally written in 10 mm to 12 mm

Subtitle is written in 3 mm to 6 mm

Notes, Dimension fig etc. written in 3 mm to 4 mm.

Space between the words is generally 2 to 5 mm in

lettering.

Inclined latter write in an inclination of 750.

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Lettering

1) Single Stroke Latter

a) Vertical

b) Inclined

2) Gothic Letter

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Lettering

1) Single Stroke Latter -Vertical

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Lettering

1) Single Stroke Latter -Vertical

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Lettering

1) Single Stroke Latter -Vertical

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Lettering

1) Single Stroke Latter -Vertical

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Lettering

1) Single Stroke Latter - Inclined

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Dimensioning

Every drawing, whether a scale drawing or a freehand

drawing, besides showing the true shape of an object,

must supply its exact length, breadth, height, sizes and

positions of holes, grooves etc. and such other details

relating to the manufacture of that object. Supplying

this information on a drawing is called Dimensioning.

Lines, figures, numerals, symbols, notes etc. are used

for this purpose.

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Dimensioning terms & notations

Dimension line: Thin continuous line. It is terminatedby arrowheads touching the outline, extension linesor Centre lines.

Extension line: Thin continuous line drawn inextension of an outline. It extend by about 3 mmbeyond the dimension line.

Arrow head: Placed at each end of dimension line.Touch outline, extension line or Centre line. Lengthof arrowhead should be three times it max width. Thespace betn them is nearly filled up.

Leader: Thin continuous line connecting a note ordimension fig with future.

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Dimensioning terms & notations

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Arrow heads

1. Open (900)

2. Open (200)

3. Closed

4. Closed and Filled

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Method of Indicating Dimension

(Aligned System)

Oblique Angular

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Method of Indicating Dimension

(Uni-directional System)

Angular

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Dimensions

Shape Identification Symbols

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Arrangement of Dimensions

1. Chain Dimension:

2. Parallel Dimension:

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Arrangement of Dimensions

3. Super Imposed Continuous (Less Space) Dimension:

4. Combined (Chain & Parallel) Dimension:

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Arrangement of Dimensions

5. Co-ordinate Dimension:

6. Dimensioning of diameters:

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Arrangement of Dimensions

7. Dimensioning of chords, arcs and angles:

8. Dimensioning of Radius:

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Arrangement of Dimensions

9. Dimensioning chamfers:

10. Dimensioning countersunks:

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Arrangement of Dimensions

11. Dimensioning Screw Thread:

12. Dimensioning Taper Future:

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Notes in Dimensions

Notes should always be written horizontally in capital

letters and begin above the leader line and may end

below also.

Further, notes should be brief and clear and the wording

should be standard in form.

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BIS–SP 46

BIS is the National Standards body formed by thegovernment of India on 1 April 1987, replacing ISI existingearlier.

The objective of BIS is to develop the industries andcommercial growth of the country by developing globallyacceptable standard for product.

It works in association with other standard-developingorganization worldwide, in particular with the ISO.

BIS has recommended & published various standards fortechnical drawings.

These standards are available in the form of IS code andSpecial Publication 46: 2003.

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BIS–SP 46

These standards are available in the form of IS code and

Special Publication 46: 2003.

In short,

The standard which is for “Engineering

Drawing Practice For Schools & Colleges”.

And used in the educational institution for

engineering drawing or graphics.

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BA

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Steps:

1. Draw both axes as perpendicular bisectors

of each other & name their ends as shown.

2. Taking their intersecting point as a center,

draw two concentric circles considering both

as respective diameters.

3. Divide both circles in 12 equal parts &

name as shown.

4. From all points of outer circle draw vertical

lines downwards and upwards respectively.

5.From all points of inner circle draw

horizontal lines to intersect those vertical

lines.

6. Mark all intersecting points properly as

those are the points on ellipse.

7. Join all these points along with the ends of

both axes in smooth possible curve. It is

required ellipse.

Problem 1 :-

Draw ellipse by concentric circle method.

Take major axis 100 mm and minor axis 70 mm long.

ELLIPSE

BY CONCENTRIC CIRCLE METHOD

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