miss. hanna’s classroom rules and describe the use of engineering drawing ... engineering drawings...

MISS. HANNA’S CLASSROOM RULES 1. “My students never fail. I believe in you and so shall you!” – Miss.

Hanna’s Quote!

2. Come to class on time.

3. Bring a positive attitude.

4. Come prepared and bring your books and notes.

5. Stay on task.

6. Complete work on time.

7. Pay attention and don’t talk while the teacher is talking.

8. Listen carefully.

9. Raise your hand to ask a question.

10.Work quietly.

11.No personal grooming, electronics which will disturb the class and other students who are working.

12.Respect personal space.

13.Ensure chairs and tables are in order before leaving class.

14.Be kind with your words and actions.

15.Respect, obey and follow all school rules and personal property.

16.Work in a safe manner.

I appreciate and thank all my students for their effort in

respecting and keeping up with our classroom rules!

A video or 2 for you

Basic Engineering Drawing http://www.youtube.com/watch?v=FFDH

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Orthographic: http://www.youtube.com/watch?v=vsnvo

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Introduction to Drawing Tools

Module Objectives

Identify and describe the use of engineering drawing

equipment.

Recognize different methods of laying out engineering

drawing papers.

Demonstrate the use of scales.

Produce a simple drawing paper layout including border

and title block.

Introduction to Drawing Tools

1.0 Introduction

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Technical drawing is the study of the procedures,

tools, supplies, skills and techniques used to record

and communicate the shape and size of a product.

Every product we have today (e.g. cars, houses,

machines, etc…), began as an "idea" in some person's

head.

Before these "ideas" became products, they

had to be drawn on paper so as to show

what the idea looks like from different

directions, Fig.1.1.

Fig 1.1.

2.0 Drawing instruments

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To prepare a drawing, one can use manual drafting

instruments as shown in Fig.1.2, or computer-aided

drafting (CAD).

If the drawing is made without either manual

instruments or CAD, it is called a freehand sketch.

The following instruments are essential and should be

available to produce a good quality

technical drawing.

Fig. 1.2: Manual

Instruments

2.1 Drawing Boards

Drawing Boards can range from simple boards,

like the one shown in Fig.1.3, to complicated

drawing machines that would be used in

engineering drawing office.

The surface of the board should

be dusted and smooth.

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Fig. 1.3: Drawing Board

2.2 T-Square

T- Square is composed of a long strip, called the blade;

it is placed on the drawing board and provides a

constant horizontal edge.

The T-square is shown in Fig.1.4 below.

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45/45 triangle 30/60 triangle

2.3 Set Square

Set Squares are best made from transparent

plastic.

The two standard set squares that are commonly

used are 30/60 and 45/45 degrees triangles as

shown in Fig 1.5.

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2.4 Pairs of Compasses

There are basically two types of compasses

1. Pencil compasses which are used to draw circles.

Circles up to 300 mm diameter are drawn using a

large radius compass.

2. Spring bow compass which is

used to draw circles of 50 mm

diameter or less. (Fig.1.6) to the

right.

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2.5 Protractor

Protractors measure angles other than those

obtained by the set squares and found in half circle or

full circle types, Fig. 1.7 shown below.

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2.6 Ruler

A 300 mm ruler with one edge marked in

centimeters and millimeters is necessary, Fig.1.8

below.

In a fully equipped drawing machine, horizontal and

vertical rulers with graduations in mm or inches

are attached to the drafting head.

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2.7 Drawing pencils

Pencils have nine grads of hardness from H to 9H and

seven grades of softness from B to 7B as shown in

Fig. 1.9.

Fig.1.9: Pencil lead grades.

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2.6 Eraser

Erasers are available in different hardness and

are used to erase pencil work.

The common eraser used is a block-shaped

vinyl eraser (Fig.1.10).

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2.8 Circle template

Circle templates are useful for drawing small

circles quickly and to join lines with a radius, A

circle template is shown in Fig.1.11.

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3.1 Sizes of the drawing paper

Drawing paper is available in ‘A’ series, ‘B’

series, and rolls of the International

Organization for standardization (ISO), but

series ‘A’ is preferred.

Paper sizes for series ‘A’ are based on the

A0 size, which has an area of 1 square

meter.

An A0 size sheet can be divided up evenly

into the various other sizes (A1, A2, A3,

A4…) simply by halving the sheet on the

long side in each case as shown in Fig. 1.12

on page 6 in Module 1.

3.0 Drawing Paper

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3.2 Scales

In order to produce drawing showing

components in detail or as plans it is often

necessary to use a scale.

This can increase the size of the drawing in

comparison to the real size of the component.

Some of the recommended scales are listed

below:

Enlargements scales: 2:1 20:1 50:1 10:1

Full (same) size: 1:1

Reduction scales: 1:2 1:10 1:20 1:100

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3.3 Layout of the drawing paper

Drawing sheets of all sizes have standard layout.

It is usual for each sheet to be provided with a drawing

frame a short distance from the edge of the paper as

shown in Fig.1.13 shown on page 6 Module 1.

Each drawing sheet has to be provided with a title block

which represents the general information source for a

drawing.

It is normally placed in the bottom and at least contains

the title of the drawing, the name of the draftsman, the

scale, and the date.

Fig 1.13 a: Layout of the A3 drawing paper.

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Fig 1.13 b: Layout of the A4 drawing paper.

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3.4 Line type

Fig. 1.14 (on page 7 in Module 1) shows the

types of line which are commonly used in

engineering drawings such as visible lines,

hidden lines, center lines, dimension lines,

extension lines, and leader lines.

Fig. 1.15 (on page 7 in Module 1) shows an

application for the use of different types of

Line.

4 Main Line Types

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Technique of Lettering

Printing increase the information that is provided on a drawing.

Printing must be clear and neat so that it is easy to read.

Use guide lines 5 mm apart as illustrated in Fig. 1.16.

These guide lines can be used to make sure that all letters and

numbers have the same size.

Always print using capital letters.

All letters and numbers should touch the top and bottom guide lines.

Guide lines should be 5 mm apart as explained earlier.

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5.1 In class activities

Draw the objects shown below in full size using different

drawing tools such as compasses, set squares and tee

square. Use an A3 sheet to create the drawing with the

same layout shown below.

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5.2 Home work

Draw all 4 drawings shown on

page 9 & 10 in Module 1

Submission date – Due next class

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Technical Drawing Instruments

Students must bring all their

drawing instruments next class

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