Basic construction lec1

Lecture 1 Sunday, 09 September 2012 1

ENGINEERING GRAPHICS1E9

Lecture 1: Introduction

Lecturer: Dr. Bidisha Ghosh ([email protected])

Course Structure

• Hand Drawing (part 1) -Dr. B. Ghosh

• Hand Drawing (part 2) -Dr. G. O’Donnell

Graphics

• AutoCAD-Dr. S. Pavia

CAE

Assessment• Examination: 75% of the overall mark

– 3 sections (A, B and C)

– 2 questions per section

– 3 questions to be answered, one from each section

• Dr B. Ghosh : Sections A and B

• Dr G. O’Donnell : Section C

• Labs 25% - assessed by coursework

– 10 % AutoCAD

– 10% D.O. Tutorials Dr B. Gosh

– 5 % D.O. Assignment Dr G. O’Donnell

Time Table Lecture

Mon

10-11 a.m.

Drawing Office practicals (AutoCAD laboratories for wks 11-12)

Mon 2-5 p.m. (group C) Tues 2-5 p.m. (group D) Wedn 2-5 p.m.( group A)

Fri 9 a.m.-12 noon (group B)

Semester 1

Wk 1 Mon 28th Sept

BG

-

Wk 2 BG BG

Wk 3 BG BG

Wk 4 BG BG

Wk 5 Holiday -

Wk 6 GO’D GO’D

Wk 7 Reading wk Reading wk

Wk 8 GO’D GO’D

Wk 9 BG BG

Wk 10 SP -

Wk 11 SP SP

Wk 12 SP SP

BG - Hand drawing I- Dr Bidisha Gosh

GO’D - Hand drawing II- Dr Garret O’Donnell SP - Autocad – Dr Sara Pavía

See JF timetable for venues


Syllabus – Hand Drawing 1

• Basic Construction

• Orthographic Projections

• Isometric Projections

• Auxiliary Views

• Perspective


Evaluation

• Examination (Sections A & B)

(2/3 of the total examination marks)

• Continuous Assessment

(10% of the total course marks)

– four drawing office tutorials


Aim of the Course

• Knowledge of engineering drawing instruments

• Understanding and interpretation of technical drawings

• Ability to develop projections of a 3D object


Reference Books• Technical Draughtsmanship

By Eanna O’Broin

• Engineering Drawing with Worked Examples

By M.A. Parker & F. Pickup

• Technical Drawing

By F. E. Giesecke, A. Mitchell,H. C. Spencer, I. L. Hill, J. T. Dygdon,J. E. Novak


Waterfall

M. C. Escher

Technical drawing is the language of engineers and designers


Topics of Interest

•Drawing Instruments

•Lines

•Dimensioning

•Basic construction


1. Drawing Board

DRAWING INSTRUMENTS 1



A Series Formats (mm)

A0 841 1189

A1 594 841

A2 420 594

A3 297 420

A4 210 297

A5 148 210

A6 105 148

A7 74 105

2. Drawing Sheets



•Layout of a Drawing Sheet


• Tee square/ Drafting Machine



• Set squares (a pair)



• Irregular/ French curves



• Compasses

• Divider

• Protractor

• Ruler/Scale

• Pencil, Eraser



TYPES OF LINES

• 3 Main Types

DRAWING LINES 1


• Lines to aid understanding

DRAWING LINES 2


DIMENSIONING 1

Dimension Lines (DL)

Position of DL


DIMENSIONING 2

Alignment of DL DL of Small Features

Dimensioning Angles Dimensioning Circles


DIMENSIONING 3


DIMENSIONING 4

Correct Practice of Dimensioning

Drawing should only carry dimensions needed to manufacture


Drawing Parallel Lines

DRAWING LINES


Drawing Perpendicular Lines

DRAWING LINES


Bisection of A Line

1. Place your compass point on A and stretch the compass MORE THAN half way to point B.

2. With this length, swing a large arc that will go BOTH above and below segment AB.

3. Without changing the span on the compass, place the compass point on B and swing the arc again. The new arc should intersect the previous one above and below the segment AB.

4. With your scale/ruler, connect the two points of intersection with a straight line.

5. This new straight line bisects segment AB. Label the point where the new line and AB cross as C.

6. Segment AB has now been bisected and AC = CB.

DRAWING LINES

A B


Divide A Line into Multiple Sections

1. From one end of the given line AB (say, A) draw a line AC at a convenient angle

2. Using a scale/ruler divide the BC into the required number of parts making them of any suitable length.

3. Join the last point on line AC (say, C) to B

4. Draw construction lines through the other points on the line AB which are parallel to CB

DRAWING LINES


Bisection of An Angle

1. Place the point of the compass on the vertex of angle BAC (point A).

2. Stretch the compass to any length so long as it stays ON the angle.

3. Swing an arc with the pencil that crosses both sides of angle ABC. This will create two intersection points (E and F) with the sides of the angle.

4. Place the compass point on E, stretch your compass to a sufficient length and draw another arc inside the angle -you do not need to cross the sides of the angle.

5. Without changing the width of the compass, place the point of the compass on F and make a similar arc. These two small arcs in the interior of the angle should be crossing each other.

6. Connect the point of intersection of the two small arcs to the vertex A of the angle with a straight line.

7.

DRAWING LINES


Find the Centre of an Arc

1. Select three points A, B and C on the arc and join AB and BC

2. Bisect AB and BC.

3. Fine the intersection point of the bisecting lines/bisectors. That is the centre of the arc.

DRAWING LINES


Inscribe a Circle in a Triangle

1. Bisect angle ABC and angle BAC.

2. Fine the intersection point of the bisecting lines/bisectors. That is the centre of the circle.

3. The radius of the circle is the length of a perpendicular line on any of the sides of the triangle drawn from the centre of the circle.

DRAWING LINES


Circumscribe a Circle on a Triangle

1. Bisect sides AC and BC.

2. Fine the intersection point of the bisecting lines/bisectors. That is the centre of the circle.

3. The radius of the circle is the length of a line joining any one of the vertices of the triangle to the centre of the circle.

DRAWING LINES


Notes for Tutorials

• The tutorials start next Monday in drawing office in

museum building

• Each tutorial is worth 2.5%

• Bring your own drawing instruments

• Drawing sheets will be provided

Students will not be allowed in the tutorial without

instruments

Basic construction lec1

Technology

Transcript of Basic construction lec1