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BASIC TECHNOLOGY

TEXTBOOK

YEAR 10

TECHNOLOGY AND EMPLOYMENT SKILLS TRAINING

Ministry of Education

03th January, 2015

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PREFACE

This text book has been written for the new YEAR 10 Integrated Basic Technology syllabus to be trialed in

Fiji secondary schools next year, 2015. It is the First edition of the Year 10 Basic Technology resource

material.

It is designed to introduce students to the fundamental techniques of technical drawing, graphics and design,

wood, metal and other common materials and processes with related knowledge on basic hand tools.

Since this is the First edition and first trial, suggestion for amendments will be welcomed.

It is hoped that for beginners for Basic Technology this text book will be relevant for them and that it

provides them the opportunity to pursue further in this field.

MINISTRY OF EDUCATION,

SUVA.

06th

January, 2015.

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ACKNOWLEDGEMENTS

This textbook for YEAR 10 Basic Technology has been produced by the Industrial Arts Section of the

Technology & Employment Skills Training Section of the Ministry of Education.

It has been written and compiled by the Year 10 text book writers‘ panel comprising of the following Industrial

Arts teachers:

1. Mr. Kelemedi Navukitu Nabua Secondary School

2. Mr. Ashwin Chand Lelean Memorial School

3. Mr. Amant A. Lal Ratu Sir Lala Sukuna Memorial School

This publication has been made possible through the support and assistance provided by the Industrial Arts

Senior Education Officer; Mr Raj I. Chand with guidance from the Principal Education Officer, TEST; Mr.

Tomasi Naborisi; Director TEST, Ms Alumeci Tuisawau and other Senior Staff of The Ministry of Education.

Above all the TEST staff and the family members of the writers are thanked for their patience and wholehearted

support.

Every effort has been made to acknowledge all copyright.

© Copyright

Ministry of Education, Fiji, 2015

All rights reserved. No part of this publication may be reproduced or transmitted in any form or means,

electronic or mechanical, including photocopy, recording or any information storage and retrieval system,

without permission in writing from the Permanent Secretary, Ministry of Education, Suva, Fiji.

Any person who commits any unauthorized act in relation to this publication may be liable for prosecution.

Published in 2015 by

Technology and Employment Skills Training

Ministry of Education

Marela House

Private Mail Bag

Suva, Fiji.

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TABLE OF CONTENTS

SAFETY 6

General Workshop Safety

Personal Safety

Hand Tools Safety

Electrical and Machine Safety

First Aid/OHS Regulations

GEOMETRY 9

Basic Technical Drawing Equipment

Preparing A3 Sheet and Paper Layout

Using the Tee & Set Squares

Styles of Lettering and Numbering

Sketching

Polygons

DESIGN & ENTERPRISING 17

Design Process

Enterprising Skills

HAND TOOLS & MATERIALS 34

Hand Tools & Appliances

Hardware

Working with Non-Metals

Finishing

Sharpening Hand Tools

GEOMETRICAL DRAWING 46

2D Drawings

3D Drawings

Prisms & Cylinders

Pyramids & Cones

JOINTS & PROCESSES 79

Wood Work Joints

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Metal Work Joints

SAFETY

Introduction Safety is the freedom from danger or risk when

planned measures or precautions are taken into

consideration to prevent injury to a person or

others. Safe practice in school premises is very

important. Practically, every school workshop

contains many potential hazards. However, with

proper control, these hazards can be eliminated.

Safety in workshop can be achieved by

appropriate implementation and adherence to the

correct safety rules. Training students in the use of

safety equipment, safety procedures and

encouraging them to create a safe working

environment are the best ways to reduce injuries

and accidents.

Workplace Safety Rules

Safety First in the Workshop Tools and machines used in the workshop, if not properly used or handled, may result in injury to the

workers and damage the tools and machines. Developing safe working attitudes and adopting safe

methods are the best ways of avoiding unnecessary injury to the workers, damage to the tools and

machines in the workshop.

A workshop is a building or place where facilities such as machines, tools and workbenches are

provided to enable a worker or student to carry out the practical tasks.

Chapter 1 Chapter 1

Outcome

s After studying this chapter students should be able to:

Identify and follow electrical, machine safety

procedures and practices in a workshop.

Practice correct safety procedures and practices

in a workplace at all times.

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Workshop safety is important because it:

Ensures free movement and a comfortable working condition.

Prevents workers from injuries.

Guides students to work in a safe environment.

Helps workers feel safe and confident.

Enables the workers to pay attention to their surroundings.

First Aid and OHS procedures in the Workshop

First aid

First Aid provides the initial and immediate attention to a person

suffering an injury or illness. In extreme cases, a quick first aid

response could mean saving a person from injury.

In many cases, first aid can reduce the severity of the injury or

illness. A quick and competent first aid response also calms the

injured person, reducing unnecessary stress and anxiety.

Some first aid tips to know in the workshop:

Always keep a First-Aid kit in the workshop and know where it is.

Get to know your working environment, in particular where to find a fire extinguisher and an

emergency stop.

Report ALL hazards, unsafe conditions and work practices.

Use the workshop in presence of a supervisor or a teacher. Avoid working alone in the

workshop.

Ensure that all passages to, from and in the workshop are completely clear.

Occupational Health and Safety (OHS)

OHS is an area concerned with the health, safety and welfare of

people engaged in work or employment. According to the OHS

Act 1996 and OHS regulation, all schools to maintain a safe and

healthy workplace for its teachers and students. The school

should have an evacuation plan which includes a map indicating

evacuation routes. This plan should be displayed on notice

boards so that it is visible when needed and using this evacuation drills to be conducted on a regular

basis.

Electrical and Machine Safety Electrical safety in schools is achieved through the proper use

and installation of electrical equipment in workshop. Also, all

users must be properly instructed concerning electrical hazards

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in their workplaces and understand the necessary safe work practices to avoid injury.

Machine hazards are a major cause of accidents and must be identified and controlled to avoid injury

to users working on or near one of the machines. Due to the possibility of serious injury, all electrical

hazards should be reported to the immediate supervisor.

Some of the following electrical and machine safety rules can ensure a safe working environment in

the workshop.

Always wear an apron or dust coat, as it will protect your clothes and hold loose clothing such

as ties in place.

Wear goggles or safety glasses equipped with side shields when working with machines. Be

sure to have enough light to see the work after wearing the protective glasses.

Keep the top of your bench and floor around it clean and neat. End your work ten minutes

earlier to properly and safely store equipment in appropriate places and to clean your

workplace as well as the workshop.

Report any electrical faults or conditions that could cause injury to the operator or damage to

machine.

Avoid talking to or distracting the attention of anyone operating a machine. If you are the

operator, do not talk to others while working. If you are an observer, stand at a safe distance

from the machine.

Do not go beyond the danger zone lines marked near machine areas. Do not attempt to touch

any worn out machine parts, electrical wires or power cords.

All personnel operating machines must be properly trained, qualified, and competent to

perform the task.

Knowing and understanding electrical and machine safety, will help you by providing a safe working

environment.

Questions

1. Describe how to dress properly in the workshop.

2. Why is it important to follow instructions or direction in the workshop?

3. Why is it important to learn how to use tools correctly?

4. What is the most dangerous thing you can do in the workshop?

5. Why is it important to report all accidents?

Activity

1. Prepare a poster based on one of the safety rules discussed in this chapter.

2. Prepare a housekeeping checklist. This list can be used during the workshop clean-up time to

help make sure tools and materials have been properly put away and the area has been cleaned.

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GEOMETRY

Technical Drawing Instruments and Standards

Technical drawing uses lines and various forms of letters and figures. The drawings must accurately represent

the shape of the object and all the details necessary to fix its size and its position must be included. As with

languages, technical drawing has its own rules. These are based on the correct use of lines, figures and other

signs.

Technical drawing is the common language of technology and industry. The manufacturer, designer, builder

and technician all use technical drawing for communication and construction.

Technical drawing has many advantages over words.

1. Drawings of two and three dimensional shapes — try describing a tool or household utensil in words.

2. Complex mechanisms — a motor cycle engine.

3. Design ideas — a bracelet; a car body.

4. Standard drawing practices throughout much of the world mean there are no language barriers.

5. There are no differences in the understanding of a drawing. Different meanings may be read into words.

Chapter 2

Outcome

After studying this chapter you will be able to:

Recognize and develop skills in orthographic

projection

Acquire the concepts in of 3rd

and 1st angle

orthographic projection

Develop the skills in pictorial drawing

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Preparing an A3 Sheet

The TITLE BLOCK

This title block is for an A3 drawing sheet

EXAMPLE

Given below is an isometric view and orthographic projection of a simple solid with dimensions

Steps in setting your DRAWINGS

1. Draw a horizontal line with a Tee-Square

2. Measure 70mm and draw the second horizontal line with a Tee-square

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3. Draw the horizontal line with a T-Square

4. Measure 50mm and draw the fourth horizontal line with a Tee-Square

5. Draw the first vertical with the longer edge of the 30°/60° set square

6. Measure 70mm and draw the vertical line with the Set-Square

7. Draw the verticle line with the set-square

8. Measure 10mm and draw verticle the line with set squares

9. Now we are left with 3 views illustrated below.

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LETTERING

BASIC STROKES

EXAMPLES

Application of Basic Stroke

Uppercase Numbers and Numerals

1. Straight Line Letters

2. Curved Line Letters

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3. Curved Line Letters and Numerals

4. Lower Case Letters

Good and Poor Lettering

SENTENCE COMPOSITION

Leave the space between words equal to the space required for writing the letter ―O‖.

Example

GOOD

NOT UNIFORM IN STYLE

NOT UNIFORM IN HEIGHT

NOT UNIFORMLY VERTICALLY OR INCLINED

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DESIGN PATTERNS

ENLARGEMENT AND REDUCTION

Plane figures which are either enlarged or reduced use ratio‘s and scale for changing the size and proportion of

their geometry. The ratios are added to determine the enlarged or reduced scale.

EXAMPLE 1

Enlarge the Regular Pentagon below to the ratio 2:5. Once the pentagon is constructed, the scale division of five

is taken from any points on the side of the pentagon.

ENLARGEMENT and REDUCTION OF POLYGONSPlain figures which are either enlarged or reduced use ratio's and scale for changing the size and proportion of their geometry. The ratio's are added todetermine the enlarged or reduced scale.

For Example;

Enlarge the regular Pentagon below to the ratio 2: 3. The ration 2 + 3 = 5divisions is placed on the scale. Once the pentagon is constructed, the scale division of five is taken from any points on the side of the pentagon.

AB

C

D

E

B'

C'

D'

E'

01 2 3

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Reduce the given Hexagon from the ration 5:2.

0

1

2

3

4

5

6

7

8

9

A B

C

DE

F

B'

C'

D'E'

F'

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EXAMPLE 2

Reduce the given Hexagon from the ratio 9:4

METHOD

1. CONSTRUCT A REGULAR PENTAGON WITH A CIRCLE GIVEN. ENLARGE TO THE RATIO 2:3

2. CONSTRUCT A REGULAR HEXAGON WITH A CIRCLE GIVEN. ENLARGE TO THE RATIO 2:3

3. CONSTRUCT AN IRREGULAR PENTAGON WITH GIVEN BASE CD:

SIDE DE = 41mm, EF=43mm, FG= 52mm and GC=47mm. DIAGONALS ARE CE=53mm and CG=57mm.

ENLARGE TO SCALE 3:4

C D

1

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ENLARGEMENT and REDUCTION OF POLYGONSPlain figures which are either enlarged or reduced use ratio's and scale for changing the size and proportion of their geometry. The ratio's are added todetermine the enlarged or reduced scale.

For Example;

Enlarge the regular Pentagon below to the ratio 2: 3. The ration 2 + 3 = 5divisions is placed on the scale. Once the pentagon is constructed, the scale division of five is taken from any points on the side of the pentagon.

AB

C

D

E

B'

C'

D'

E'

01 2 3

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Reduce the given Hexagon from the ration 5:2.

0

1

2

3

4

5

6

7

8

9

A B

C

DE

F

B'

C'

D'E'

F'

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EXAMPLE 3 EXAMPLE 4

EXERCISE

1. CONSTRUCT A REGULAR OCTOGON WITH A SIDE 25mm IN LENGTH. ENLARGE TO SCALE 3:4

2. CONSTRUCT A REGULAR OCTOGON WITH A SIDE 35mm IN LENGTH. ENLARGE TO SCALE 2:3

3. CONSTRUCT AN IRREGULAR PENTAGON WITH GIVEN BASE CD:

SIDE DE = 42mm, EF=44mm, FG= 54mm and GC=48mm. DIAGONALS ARE CE=52mm and

CG=56mm. ENLARGE TO SCALE 3:4

4. CONSTRUCT A CIRCLE OF RADIUS 25mm AND CONSTRUCT A REGULAR HEPTAGON WITHIN

THIS CIRCLE SUCH THAT EACH CORNER FALLS ON THE CIRCUMFERENCE OF THE CIRCLE.

ENLARGE ITS OVERALL SIZE PROPORTIONALLY BY A RATIO OF 2:3

5. CONSTRUCT AN IRREGULAR HEXAGON, GIVEN THE BASE, SUCH THAT THREE OF IT‘S

INTERNAL ANGLES ARE 110° EACH AND ALL THE SIX SIDES ARE EQUAL IN LENGTH. ENLARGE

ITS OVERALL SIZE PROPORTIONALLY BY A RATIO OF 3:4.

6. CONTRUCT A TRIANGLE ABCD, GIVEN BASE AB, IF AC=50mm AND BC=90mm. ENLARGE THIS

TRIANGLE TO A SCALE OF 2:3

7. CONSTRUCT A 60mm x 50mm PARALLELOGRAM WITH AN INTERNAL ANGLE OF 60°.

ENLARGE THIS PARALLELOGRAM TO A SCALE OF 3:4

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DESIGN AND ENTERPRISING

Introduction

The designing process is seen by many as a constant search for better solutions to our needs.For

example , good industry employers constantly use the designing process as they try to improve

products and processes.It involves working through a series of linked steps that lead to solving a

problem or satisfy a need.

Developing skills with this designing process takes practice.While using the process in different

situation learners will gain confidence and success. Most people get a lot of enjoyment from designing

and making something useful,or solving a problem or reaching a decision about a difficult situation.

Designing and Problem Solving.

They both use the same designing strategy or process to reach a solution. The designing process

usually results in an actual product or process involving materials and information.

Problem solving uses the designing process to lead to a decision or solution.This may not involve a

product.Problem-solving or decision making is not always concerned with technology and is useful in

situtions such as buying of tool, planning a party or festival, choosing a study program, planning a

holiday or trip, making choices, finding an engine problem and working out how to do something.

In these examples,the outcomes do not involve the production of a final product or process.

Chapter 3

Outcome

s After studying this chapter students will:

Identify,understand and interpret the relevance of the

cycle in designing.

Identify and differenciate the traditional local design.

Recognise the important of recycling and

sustainbility in design.

Recognise and develop enterprising skills and

characteristic through planned tasks and projects.

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Technicians in the appliance service and automotive industries are very involved in problemsolving,

but less so in designing.

Important of Using Design Process

Solutions to designing tasks are rarely reached in a disorganised way. You rarely find good solutions

by chance.

The use of an orderly process always leads to better decision or solutions. This process helps ensure

that important things are not overlooked.

Designers are more likely to produce better results as they develop confidence, experience, and

practice skills with the designing process.

What is the designing process?

The designing process involves four linked main stages:

Investigating the problem, ideas for solutions, and information about ideas.

Designing solutions

Producing the final solution

Evaluating the outcomes.

SUMMARY

Designing usually leads to actual products.

Problem –solving uses the designing process to find a solution or decision that may not involve

a product.

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You can use this process for most designing tasks, no matter how complex. Some design tasks are

relatively quick and simple-others can be complex and difficult.

INVESTIGATING

INVESTIGATING

o Investigating the design brief:

o Clarify the problem

o Note expectations or specification

about solution;

o Explore issues about the problem

o Investigate ideas of solutions

o Find information about ideas

o Evaluate and document your Design Folio

DESIGNING

o Identify the most likely ideas.

o Develop and refine the idea.

o Devise the proposed solution

o Model or trial the proposal

o Evaluate and documents

your Design Folio

EVALUATING

o Think about the outcome

o Does it meet the design brief?

o How well does it work?

o Could it be improved?

o What remains to be done?

o Complete your design folio

PRODUCING.

Produce the solution that can involve any making

activity example

o Built and test a protoype

o Implement a decision

o Construct, establish, build, etc

o Repair tasks

o Evaluate and document your design folio

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A large designing task can have many small designing tasks embedded in it. For example, the process

of designing a car or a building can have hundreds of small design tasks, for various parts, within the

main task.

Designing is much more than simply drawing plans, shaping, styling or decorating. These activities are

important, but they are only a small part of the designing process.

Are all stages of the process necessary?

All stages of the designing process are important, and each

stage must be included in any designing task. For some tasks

you may need to spend more time on one stage of the

designing process than others. For example, an electric

security lock on door could take a lot of planning and

development work, but the final solution may quite easy to

build.

Where does the process start?

All designing or problem-solving tasks start with a need. However, different tasks may require the

designer to enter the designing process at different points.

For example, a designer can start with a new design brief, and move through the investigating-

devising-producing-evaluating process. Another situation may start with an existing product that

needs to be repaired, modified or improved. In this case, the designing process is evaluating-

investigating-devising-producing-evaluating.

Review progress at each stage

At each stage of the process, you have to make many judgements and decisions. It is important that

you evaluate your process and the decisions made at each stage. Do not wait for the final evaluation

stage.

Working with others

Wherever possible, work with others throughout the

designing process. Discussion and cooperative activity

will normally produce better results.

When working with others decisions will be shared or

sometimes settle conflicts as the group works through

the process.

Documentation

Keep records of all stages in all stages in the designing

process. Do not throw anything away, even rough ideas‘

sketches, brainstorming notes, or results of test or

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experiments made. It is necessary for every designer to document every material in Design Folio for

assessment as evidence of the process used.

The type of documentation needed will depend upon the task for the audience or client. This will be

clear at the design brief stages. Documentation will be done on some certain stages and for other task

Design Folio to be prepared to cover he total process.

For oral presentation about the proposed solution different material such as charts, or pictures to be

presented. Graphics are an important part of the designing process. The type of graphic used must suit

the task and the stages of the design process. At the investigating and designing stages, for example,

you may only need ‗thumbnail‘ concept sketches or flow charts. Your final drawing must comply with

normal drawing conventions.

INVESTIGATING THE BRIEF

The design brief is a statement about the needs or problem and any expectations or specifications

required for the solution. A design brief is like a contract, because it sets out all the conditions and

specifications that to a situation. The design brief outlines the problem or need, the task expected to be

undertaken, any specifications for the solution, and any special conditions

The design task is easier to tackle if the design brief is clear and precise. If the brief is not clear, design

work may be misdirected. In some cases the design brief will list some essential outcomes that must be

met. It may also list some desirable outcomes. These are not absolutely essential.

Clarify the problem or the need.

Investigating and clarifying the problem is the first important step along the path to a solution.

Thinking and discussion of the problem should have some background reading.

Specifications and limitations

In designing tasks, some factors are set and beyond the designers control. This will place limits on the

designing process. These could include:

Time: the solution may be needed by certain date.

Processes: the tools and equipment available may influence the processes to be used.

Materials: the choice of materials may be defined, or be limited to those available.

Cost: there may be limited budget.

Performance specification: the solution may have to satisfy some performance requirements.

Operational requirements: where and how the solution will be used.

Discussion

What does this statement mean?

Check list-The design brief

Do you know what is expected of you?

Details about the folio required?

Are requirements about the task clear?

Due date for drafts and final report.

Don’t ask the designers to build a bridge .Ask them how to get across the river.

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INVESTIGATING IDEAS

The ‗investigating ideas‘ stage of the designing process is vital.

Good solutions depend upon good ideas. Some background

reading or discussion with others may help you with

understanding the problem set in the design brief. Internet,

encyclopaedia, magazines and textbooks can be useful.

A range of ideas gives the designer many options for possible

solutions to the problem. Investigate a lot of ideas, no matter

how unlikely they may be seem and often, these ideas can lead

to surprising and creative solutions.

Work with others where possible, and discuss as many ideas as you can think of.

Good designers try to be creative.

The easiest way to get ideas is from our own background and this will improve with experience and

confidence. There are many ways to get new or better ideas

Successful designers try to think creatively about problems. They question the obvious or traditional

ways of dealing with things, and try to look at situation from different angles. They do not limit there

thinking by using traditional solutions.

Good designers try to be imaginative, and approach their work with a sense of fun.

Designers always look for better ideas and solution that are simple, elegant and effective.

Effective designers are hardly ever satisfied with their first ideas, and search for better ideas.

Brainstorming is a useful and enjoyable way to produce creative ideas. Usually it involves a group,

where everybody contributes ideas.

Check list-Investigating ideas

Evaluation of the ‘Investigating Ideas’ stage

Is the design brief clear?

Is the task clear?

How will you find good ideas?

How will you find creative ideas?

Will you contact or interview resource people for ideas? (who)

Will you use range of resources to get ideas?

How have others handled this problem? Are there any existing ideas or solutions that

could help you with the task?

Have you found useful range of ideas?

Have you found several creative ideas?

Have you found several ideas that appear to be likely solutions?

Have other people been involved in developing ideas?

Have you discussed the ideas with others?

Have you made notes and sketches about the ideas?

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INVESTIGATING INFORMATION ABOUT IDEAS.

An idea is only a starting point or option for a solution.

Before an idea to be considered as a likely solution,

there is a need to more about it. For example using an

idea involving certain material; the following

information about the cost, sizes, availability, and

properties is needed. These are factors to help in

analyses.

The investigating ideas stage and investigating the

information about ideas stage are closely linked, and you may need to move backwards and forward

between two stages many times-as you make decision about information you are analysing.

Sometimes the ideas will be rejected because of the information found; it may be too costly, material

may not be available in the sizes needed, or the idea may be unrealistic or not practical. This is the

analysis stage or thinking stages.

The information will be gathered by talking, listening and observing, internet and reading reference

book. The more literature available, the more important it is to know where and how to find useful

information. Often the information you find can lead to new ideas.

Evaluation of the investigating information stage

DESIGNING MOST LIKELY SOLUTION

Designing process you have to sort out likely solutions and make some careful judgement.

At this stage, you should have considered many ideas, and gathered information about all ideas that

could be likely solutions.

You must choose the idea that seems most likely to be successful. The designer has to predict the way

this idea will work, or how it will work or how it will look.

You may have to choose the best of the several potentially good solutions. It may be that none of the

ideas may be ideal, but choose the best at this stage, unless you consider it to be unsatisfactory because

it does not meet the design brief.

Have you got all the information you need?

Was enough information available for you to make decisions about using the idea?

Is the information opinion or fact?

Is the information detail enough

Have you cross-checked important information?

Do you need more information?

Is the information useful?

What evidence supports the information?

Is the information up-to-date?

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At this stage you need to develop and refine the idea, taking it from an ‗idea‘ stage to a more detailed

proposal. You may need to test the proposed solution (eg. building a model or mock up‘).

Evaluating the proposed solution

Traditional Knowledge in design

Although classified as non-scientific, the traditional knowledge has been accumulated after centuries

of extensive trial and error experiences from which people have learned. In the sub-tropical conditions

in the Pacific Islands, people have used traditional knowledge to live off the environment on which

they depend for food, supplies, medicine and culture. An appreciation of some of the traditional

knowledge will provide an insight into how the people use and depend on their environment and its

resources. Traditional knowledge can be the basis on which scientific research is utilised to explain the

details that up to now may be unknown or unexplained.

Traditional method of building

Pacific islanders have been dealing with a changing environment for centuries. Adaptation to change is

part of the lifestyles of the Pacific community, and traditional knowledge, values, and practices—or

intangible cultural heritage (ICH)—underpins the ability of the Pacific community to successfully live

and thrive in the Pacific environment. In synergy with other scientific knowledge, ICH may enhance

the communities‘ resilience against natural disasters and climate change. Consideration for culture

should be integrated into reducing disaster risk and adapting climate change policies, plans, and action.

Traditional Navigation System

The Pacific, with its land and oceanic areas, spans one third

of the planet. Traditional navigation systems are the most

important ICH elements shared by Pacific communities. For

centuries, Pacific navigators have used a wide range of

traditional knowledge and techniques related to weather

patterns and signs to guide their long ocean voyages. Such

techniques rely upon following observations.

Safeguarding traditional navigation systems reminds not

only the Pacific community but also the entire world of the

ancient knowledge and skills of humanity and of the respect to nature and universe.

Does the proposed solution meet the design brief?

Why have you selected this solution?

Have you tested, modelled, or simulated the proposed solution?

What were the results of these tests?

Were any changes required?

How readily can the solution be produced?

Have you selected the most suitable materials?

Have you considered the properties and appearance of materials?

Is the cost of materials acceptable?

Does the solution need packaging or labels?

Are there any dangerous parts?

What will happen if the product breaks?

Can the product be stored properly?

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Traditional Farming Systems

The traditional farming systems in the Pacific have a

number of mechanisms that allow for sustainable

production and a supply of agricultural products. These

mechanisms include the production of surpluses, the use of

emergency food resources, control of food consumption,

and the maintenance of agricultural resilience through

diversifying crops. These systems have enabled Pacific

island communities to mitigate the risks and effects of

climatological extremes and to ensure food security. The

common examples of traditional knowledge across the

Pacific are traditional calendars that guide agricultural

planning and harvesting of forest and agriculture products. Tongan farmers have their own calendar

around which farming activities revolved. According to this traditional calendar, the year comprises

thirteen lunar months, where each lunar month consists of twenty-eight days. The Tongan calendar

plays a role when smallholders make decisions about planning, harvesting, and other

Traditional Fishery Systems

Several traditional fishing control practices have

been put in place in the Pacific through different

types of customary marine tenure. These practices

include limiting access, closing fisheries during

certain seasons, establishing no-Examples include

the no-fishing or tabu areas of Fiji,Vanuatu, and

Kiribati; the ra’ui in Cook Islands; the masalai in

Papua New Guinea; and the bul in Palau. These

traditional fishery-management practices have

served as measures for sustainable resource

management and ecosystem protection. They have

also constituted important living food reserves for

communities.

Traditional architecture

There are many examples of traditional building

methods in Pacific islands. Due to the frequency of

natural disasters in the region, many building styles

demonstrate the traditional Fijian bure, which is

mounted on a high stone foundation to prevent

flooding and storm surges. It has a high dome ceiling

to combat humidity and has open sides to allow

winds to pass through. Such traditional dwellings

incorporate architectural styles that enable them to

withstand extreme weather and strong winds. Even

in the event of the structure failing, replacement

materials are readily available and sustainable, and the collapse generally would not injure the

inhabitants. Many of the traditional aspects of vernacular housings in the Pacific have eroded with the

introduction of Western building techniques and materials, Including corrugated iron and concrete.

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Construction is often unregulated, and buildings are not built according proper building standards and

codes. This makes the Western-style buildings more vulnerable to environment.

Design for recycling

What is design for recycling?

The designed-for-recycling1 method incorporates

recycling and recyclability criteria into the design

phase of products, with the aim of obtaining recycled

and/or recyclable products. The environmental

variable is just another requirement of the product that

is added to all the others, such as its cost, its safety, its

manufacturability, its use, etc. The application of this

variable does not affect the rest of the properties of the

product, and price and environmental improvement

are combined with the aim of manufacturing products

with a reduced environmental impact associated to its entire life cycle and competitive prices.

What are products designed for recycling, or in other words, recycled and/or recyclable

products?

Recycled products are those which are manufactured using recycled materials or components from

products no longer in use. Recyclable products are those that are manufactured to be recycled at the

end of their useful life. In other words, mono-materials are used, the toxic and hazardous substances

are eliminated and a modular manufacturing system is used that produces easily-dismantled products,

compatible materials are used, material that is difficult to use is identified by means of codes, and so

on.

Why recycle?

Recycling is a daily activity for more than 100 million Americans and a great way to protect our

environment and stimulate our economy. Recycling saves resources, prevents pollution, supports

public health, and creates jobs. It saves money, avoids landfills, and best of all, it‘s easy. To

understand the value of recycling, we must look at the entire lifecycle of a product ― from the

extraction and processing of raw materials, to the manufacture of the product, to its final disposal.

Recycling creates a closed-loop system where unwanted products are returned back to manufacturers

for use in new products. This prevents the pollution and destruction that occurs when virgin materials

–like trees and precious metals– are extracted from the ear.

Benefits of Recycling

Reduces the amount of waste sent to landfills and incinerators;

Conserves natural resources such as timber, water, and minerals;

Prevents pollution by reducing the need to collect new raw materials;

Saves energy; gas emissions that contribute to global climate change

What are the benefits of recycling?

We cannot sustain our consumerist lifestyle without getting inundated by garbage and exhausting the

earth‘s resources. The products that we use are wrapped in several layers of packaging material that

are perfectly recyclable – plastic, aluminium, paper, tin, wood, etc. Solid waste disposal experts

27

engage in an uphill struggle to contain this virtual avalanche of garbage we produce every day. It is

apparent that digging a hole, a landfill, is clearly not the answer. Sooner or later, the waste becomes

uncontainable and will spill into our farming areas, forests, and water sources.

Reason for recycling.

Financial Income – There is money in recycling. In the level of the individual, one of the benefits of

recycling is financial INCOME. There are a lot of things lying around the house that we no longer

want or need that might just end up in a dumpsite somewhere, that we can recycle AND EARN

MONEY from. Cell phones, PDAs, ink cartridges, etc. Here at Pace Butler, for instance, a phone sent

in for recycling could net the owner as much as $50.There is also the financial benefit for the

communities who recycle in that there will be reduced costs of waste disposal or recycling. You think

recycling is expensive? Consider these recycling facts: aluminium cans are the most valuable item in

your bin. Aluminium can recycling helps fund the entire curb side collection. It‘s the only packaging

material that more than covers the cost of collection and reprocessing for itself.

Recycling helps conserve limited resources – Throwing away a single aluminium can, versus

recycling it, is like pouring out six ounces of gasoline. Last year, Americans recycled enough

aluminium cans to conserve the energy equivalent of more than15 million barrels of oil. Here are some

compelling recycling facts from the Pennsylvania Department of Environmental Protection.

Recycling is energy efficient – On a larger scale, recycling could translate into huge reductions in our

energy costs. Consider these facts: It costs more energy to manufacture a brand new aluminium can

than it does to recycle 20 aluminium cans. 20 cans can be made from recycled material using the same

energy it takes to make one new can.

Recycling builds community – In almost all communities in the country today, there is a growing

concern for recycling and the environment. People are working together in recycling programs,

lobbies, and free recycle organizations to help promote recycling. We will be featuring these groups in

our upcoming posts and link with the various networks to help you locate the nearest recycling center

or free recycle group nearest your location.

Recycling creates jobs – Incinerating 10,000 tons of waste creates one job; landfilling 10,000 tons of

waste creates six jobs; recycling 10,000 tons of waste creates 36 jobs.

Recycling builds a strong economy – Done on a nationwide scale, like what we‘re doing here in the

US, recycling has a huge impact in our economy in terms of jobs, energy cost reduction, resources

conservation. Lately, as the price of oil hits close to $120 a barrel, people have become more aware of

the huge impact of recycling, particularly in reducing plastic waste material coming from the bottled

water and beverage industry. We will be discussing this in detail in our future posts.

Recycling is Earth-friendly – No matter how safe and efficient our landfills are being billed to be, the

possibility of dangerous chemicals coming from the solid waste deposited in these landfills,

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contaminating underground water supply is always present. Combustion or incineration of our solid

waste is effective and energy-generating, but we pay the price in increased air pollution.

Activity

1. Explain the difference between modern and traditional designs support your answer with two

examples.

2. What do you mean by ―design for recycling‖?

3. List and briefly explain five reason why design for recycling?

4. What are some benefits for recycling?

Green Design

Sustainable design (also called environmental design,

environmentally sustainable design, environmentally

conscious design, etc.) is the philosophy

of designing physical objects, the built environment, and

services to comply with the principles of social, economic,

and ecological sustainability.

Where We’re Going: Education for Sustainability

Today, our students are encountering a rapidly changing and interconnected world. Because of this, it

is time to broaden environmental education to a more comprehensive view of the world that includes

teaching about the environment, as well as the social constructs of culture, society, governance, and

economics. Our quality of life, now and in the future, will ultimately depend upon humans‘

comprehension of their role in a world of interdependent environmental, economic, and social

systems. The goal of education for sustainability is to develop the capacity for society to meet the

needs of today while assuring intergenerational equity – that is, creating opportunities for a positive

present and a hopeful future.

What is a System?

A system is a group of interacting, interrelated, and interdependent components that form a complex

and unified whole. Systems are everywhere. For example, a classroom, a predator/prey relationship,

and the ignition system in your car are all systems. Some systems are ―nested‖ within larger systems.

For example, the circulatory system is nested within the system we know as the human body. A

system is a collection of ―things‖ in which the whole is greater than the sum of its parts.

What is Sustainability?

The most well-known definition of sustainability – ―meeting the needs of the present without

comprising the ability of future generations to meet their needs‖ – comes from the Brundtland Report,

which was the product of a United Nations commission in 1989.

What is Sustainable Design?

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Sustainable design considers how to design the built environment in a way that cultivates ecological,

economic, and cultural conditions which support human and environmental well-being, indefinitely

(Ann Thorpe, The Designer‘s Atlas of Sustainability, 2007).

Sustainable Design offers the possibility of building schools, office buildings, parks, transportation

systems, and entire communities with an eye toward long-term sustainability, rather than only seeking

to solve immediate needs and desires. It supports city planners, architects, and designers in

approaching each project with the intent to reduce environmental impacts, stimulate the economy, and

provide opportunities for people to connect with each other and the land.

Sustainable design takes a systems-wide perspective. It aims to solve current environmental problems

and prevent future ones from occurring while integrating a wise understanding of social and economic

factors and their impact on the environment.

Common Principles of Sustainable Design

There are some common principles associated with sustainably designed products and processes.

These include:

Use of low-impact materials: Chooses non-toxic, sustainable, or recycled materials, which require

little energy to process. Takes into consideration how the materials (visible and invisible) originate in

and return to the ecosphere (atmosphere, lithosphere, biosphere, and hydrosphere).

Energy efficiency: Implements manufacturing processes that use less energy and produces products

which require less energy to manufacture and operate. Ideally, makes use of renewable energy sources.

Quality and durability: Understands that longer-lasting and better-functioning products will have to

be replaced less frequently, thereby reducing the impacts of producing replacements and disposing of

worn-out products. Another option is flexible designs that have a core component, such as an

automobile chassis, that remains durable, but other components that can be replaced and upgraded

over time as better versions become available, such as the engine and transmission.

Cradle-to-cradle life cycle design for reuse and recycling: Designs products, processes, and systems

for performance in the commercial ―afterlife‖ of the product. This includes choosing materials with a

cradle-to-cradle approach, so that the materials themselves create clean water, clean air, or can be

composted to enrich the soil. This also includes design to facilitate the eventual separation of

―technical nutrients‖ for the industrial process of manufacturing from ―organic nutrients‖ that will

biodegrade and enrich natural systems.

Bio mimicry: Designs products, services, and industrial systems to mimic biological designs and

cycles found in nature. Natural systems, large and small, are models of interactive functionality that

maximizes effectiveness and efficiency.

Service substitution: Promotes the sharing of products or services among groups of people. For

example, encouraging people to change from private automobile ownership to joining a car-sharing

service. Such a system promotes minimal resource use per unit of consumption (e.g., per car trip

driven).

Local renewable resources: Chooses materials from nearby (local or bioregional), sustainably

managed, renewable sources. Ideally, when their usefulness has been exhausted, biodegradable

resources can be returned to nature as biological nutrients, or alternatively, returned to manufacturing

as technical nutrients.

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Carbon footprint: Reduces an individual‘s carbon footprint by choosing products and services that

have been sustainably designed, sustainably produced, and have the ability to be recycled or reused.

Environmental health: Aims to reduce or eliminate human health risks from environmental factors

(such as pollution, heavy metals, etc.) that can be ingested, inhaled, or absorbed through the skin.

Environmental justice: Aims to provide all people with access to a healthy environment and equal

access to decision-making processes. The development and enforcement of environmental laws,

regulations, and policies should fairly involve all people and should protect groups of people from

being disproportionately affected by environmental health hazards.

Human needs and quality of life: Considers how a design can promote human needs and quality of

life in terms of subsistence, protection, affection, understanding, participation, leisure, creation, and

identity.

Design for change: Considers what policy changes, behavioural changes, and technology changes will

enable a design to occur, and what changes will exert the greatest leverage for overall sustainability.

Examples of Systems and Sustainable Design Projects

The following chart provides examples of different systems and a few corresponding sustainable

design project ideas.

SYSTEM POSSIBLE SUSTAINABLE DESIGN PROJECTS

Built

Environment

Create a manual to help schools in your district choose green

building materials and interior fixtures.

Design and build a rain garden at your home or school.

Energy

Conduct an energy audit of your home, school, or

community and develop/implement an energy efficiency

plan.

Compare solar, biomass, wind turbines, and geothermal

energy sources and develop a renewable energy plan based

on this analysis.

Water

Conduct a water use audit of your home, school, or

community and develop/implement a water reduction plan.

Conduct water quality testing at different locations within

your watershed (e.g. creeks, rivers, Puget Sound, and marine

estuaries) and design/implement a plan to improve water

quality.

Design an art piece that teaches about your local watershed.

Waste

Conduct a solid waste audit of your home, school, or

community and design a plan to encourage the reduction,

reuse and proper recycling of waste.

Design a program to encourage school-wide recycling.

Design and build a composting system at your home.

Develop a system to encourage your teachers and school

office workers to reduce their paper use.

Workplace Health

& Safety

Conduct an ergonomics audit of a work station or process at

a local job site and design a healthy worksite product such as

a chair, writing implement, or electronic device.

Survey health and safety hazards at a local employer and

offer recommendations on how to protect workers.

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Social and Civic

Action

Survey registered voters who do not vote to find out what

impediments keep them from voting. Design and disseminate

ideas to minimize those impediments.

Work with a local non-profit agency to help design a system

that encourages and rewards volunteerism in the community.

Food & Farm

Explore where food in your school/district comes from and

design an incentive plan to encourage the procurement of

products from local farmers.

In partnership with local elementary school students and

teachers, design and plant an organic garden for the school.

Develop an educational program about community supported

agriculture.

Choose a food item (such as a pineapple) and map its

pathways, and environmental impacts, from the farm to your

plate and share that with community members.

Technology

Map the cradle-to-grave (life cycle from development to

waste) pathway of electronic waste and design a product that

following the principles of cradle-to-cradle (a product whose

life is continuous, never ending in a landfill).

Culture

Identify a landmark, building, park, or other place that has

cultural importance in your community. Design a brochure,

interpretive sign, or other type of media to tell its story and

to educate people about its importance.

Film a documentary in which you interview community

elders about local history.

Media, Music, and

Art

Organize a festival that features film, music, and art

celebrating your community‘s environment, culture, or

economy.

Develop an art program that inspires children to create

sustainability-themed art.

Transportation

Conduct a rush hour count of carpools versus single-

occupant vehicles along a local freeway or highway and then

develop an incentive program to encourage people to bike,

walk, bus, or carpool to school or work.

Develop a cost/benefit assessment of transportation modes,

such as car, bike, motorcycle, and bus and design an

alternative transportation plan that is economically viable

and socially appropriate for your community.

Parks & Natural

Areas

Write an interpretive guide for a local nature trail or park.

Develop a plan for removing invasive plant species from a

local park.

Forestry

Investigate the effects of bio solid fertilizers on tree growth

and design a plan or product to sustainably enrich forestry

trees.

Calculate the amount of wood re-used and the reduction of

environmental impacts by Urban Tree Salvage Program (e.g.

in King County) and then design an outreach campaign that

encourages builders to use salvaged wood products.

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Environmental

Health & Justice

Conduct a survey of a local immigrant group to find out what

environmental health risks most concern them and then

create educational materials in languages appropriate for

your community.

Create educational materials to encourage low-income

women in your community to get mammograms.

Principles of Design

1. BALANCE - Balance in design is similar to balance

in physics. A large shape close to the centre can be

balanced by a small shape close to the edge. Balance

provides stability and structure to a design. It‘s the

weight distributed in the design by the placement of

your elements.

2. PROXIMITY - Proximity creates relationship

between elements. It provides a focal point.

Proximity doesn‘t mean that elements have to

be placed together; it means they should be

visually connected in some way.

3. ALIGNMENT - Allows us to create order and

organisation. Aligning elements allows them to

create a visual connection with each other.

4. REPETITION - Repetition strengthens a design by

tying together individual elements. It helps to

create association and consistency. Repetition can

create rhythm (a feeling of organized movement).

5. CONTRAST - Contrast is the juxtaposition of

opposing elements (opposite colours on the colour

wheel, or value light / dark, or direction -

horizontal / vertical). Contrast allows us to

emphasize or highlight key elements in your

design.

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6. SPACE - Space in art refers to the distance or

area between, around, above, below, or within

elements. Both positive and negative space is

important factors to be considered in every

design.

Balance – shows symmetry in the composition

Movement – elements show movement or action

Contrast – The elements are opposing one another i.e., big against small, light against dark

Emphasis – artist directs the eye to one part of the composition

Rhythm – the same elements in a pattern vary in size or direction

Harmony – elements are similar in size, shade or shape

Variety – elements are different in size, color or shape

Activity

1. What is green design?

2. Why is green design important in our community?

3. What is sustainable design?

4. List and briefly explain four common principles of sustainable design?

5. List 4 different systems and write down their possible sustainable design project?

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HAND TOOLS AND MATERIALS

Introduction Every workshop should be well equipped with a number and

variety of tools and equipment for work to be done efficiently.

Although you may not be using all the tools at this level, it is

necessary to be familiar with these tools, also able to identify and

select right tool for the job, and use it safely and correctly. Many

non-wood materials such as metals and alloys, plastics, leather and

glass are widely used in the woodwork industry. Therefore, it is

necessary to know something about these materials. This chapter

displays the basic hand tools and appliances, hardware used in joinery, metals and non-metals used in

woodwork and some types of finish applied to these materials.

Hand Tools and Appliances All hand tools and appliances must be used for their intended purpose. Hand tools must be inspected

before and after use. The use of any hand tools should be stopped if it becomes unserviceable during

operation.

1. Combination Square

A combination square is a tool used for multiple

purposes in woodworking. It combines several of the

features of measuring and marking tools.

The combination square can be used for leveling, as a try square,

to determine the squareness of a piece of joint.

It can also be used as a saw guide.

Vial

stainless steel blade

Chapter 4

After studying this chapter students should be able to:

Identify and familiarize with basic and

common hand tools.

Exhibit their competency in appropriate, safe

and effective use of these hand tools.

Outcome

s

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2. Sliding Bevel

A sliding bevel is a tool which can be set to different angles

to aid marking out. It is composed of two parts, the stock and the

blade. The stock is usually made from rosewood which is a high

quality material. The blade is made from hardened and tempered

steel. It is used to mark lines at any angle on a work piece.

3. Sash Cramps

Sash clamps are used to clamp work together when it is glued.

They vary in size and are normally used in pairs.

When in use, the sash clamp is placed below the work to

be glued / assembled. The slides are arranged on either side

and scrap wood is placed between each face and the work.

This protects the work when the thread is tightened.

4. Hand Saws

Hand saws are hand-held tools, manually-driven, that are designed to cut through softer materials

mainly wood. There are many different types of hand saws that vary based on how and what they cut.

(i) Keyhole Saw

A keyhole saw is perfect in cutting holes

in wood and curves. Its blades are mounted on handle that is made of

metal, wood or plastic and shaped like that of a hand gun.

It is used for cutting holes in soft woods or in drywall, such as cutting

a hole in a wall for a new electric switch.

To safely use a keyhole saw, select the appropriate blade and firmly attach it to

the handle. Depending on the material being cut, a starter hole may need to be

drilled in the wood or drywall so the tip of the keyhole saw can be inserted.

(ii) Cross Cut Saw

A cross cut saw has wide alternating bevel teeth perfect for rough

cutting on wood grains where tearing out is not important. Its saw

blade ranges from 55 to 70 cm with 3 to 5 teeth per cm.

It is used to cut large pieces of timber or cuts through a tree

across the grain of timber.

For safety, always be aware that the teeth of a crosscut saw are sharp and

pointed. Placing them point-down on an object or a body part will cut it.

(iii) Panel Saw

Panel saws are perfect for cutting small pieces of wood. It is shorter

compared to regular hand saws and is useful for its portability. Panel

saw length can be as short as 46 cm with 3 to 5 teeth per cm.

It is especially used for cutting light boards like plywood across the grain.

Blade

Stock

Thread

Head Slide

Bar

Blade

Handle

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(iv) Rip Cut Saw

A rip cut saw is an aggressive, push stroke handsaw with sharpened

teeth top. Its saw length varies from 60 to 70 cm with 2 to 3 teeth

per cm. It is specially designed for making cut parallel to the direction of the

wood grain.

(v) Back Saw

Back saws are used for trimming and fine woodcutting.

Its teeth are smaller compared to other types of hand saws grouped

tightly together to achieve a fine cut. There are various subtypes of

back saw like the Mitre saw, Dovetail saw and Tenon Saw. Back saw

blade size can range from 20 cm to 40 cm.

It is used for making fine accurate cuts in small pieces of wood

such as cutting of joints, angles with and across the grain.

(vi) Coping Saw

Coping saws are perfect for cutting complex patterns on wood. It has

a sprung steel frame with a wooden handle that can be turned to tighten

the blade. A coping saw is a pull stroke hand saw.

(vii) Hacksaw

Hacksaws have fine, disposable blades held in tension by front

and back pins. It is used in metal cutting such as thin tubing and

drill rod with its 7 to13 teeth per cm. Its finer blades can also

cut through cables, wire ropes, light angle irons and channels.

A hacksaw is a push stroke hand saw.

It is used to cut rods, bars, angle plates to required lengths and sheet

metals to specific size and shape.

5. Ratchet Brace and Bits

Hand-operated tool for boring holes in wood, consisting of a

crank-shaped turning device, the brace, that grips and rotates

the hole-cutting tool, the bit. The bit goes into the wood as the

handle is turned. Pressure is applied to the top and the tool is

rotated with a U-shaped grip.

The ratchet must be reliably operational for both direction and

the jaws must hold the tapered tang twist bits, and the dual

purpose combination bits firmly and concentrically.

Hardware for Joinery There is wide range of hardware available for joinery works. This section focuses on handles, hooks,

hasps and hinges used in joinery works.

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Handles The right handles selection and positioning can transform the look of your kitchen units and doors,

taking them from ultra-modern to elegantly traditional.

Door Handles

Doors generally have at least one fixed handle,

usually accompanied with a latch. However,

other types of handles are also used depending on

the thickness and type of door.

Latch Handles Are for internal use and usually mounted on a back plate. They are used in conjunction with a tubular

mortise latch and suitable for use with doors

that are of 35-44mm thickness.

Lock Handles Have a keyhole cut for use both internally and externally where a lock is

required and are used in conjunction with mortise sash locks. They are

suitable for use with doors that are of 35-54mm thickness.

Hooks

Whether you want to hang a coffee cup or support a clothes line, you will be able to find a hook of the

right size and shape to do the job. Use large hooks for heavy objects; a small hook may bend or pull

away from the surface when supporting a heavy load. Before installing a hook that screws into place,

make a pilot hole with a nail or drill.

(i) Screw Hook has a threaded end that screws into wood,

ceilings or walls. The open end supports various items. The rounded

tip hook is for household uses; pointed tip is for suspended ceilings.

The L-shaped hook supports wide objects.

(ii) Swag Hook combines a hook with a toggle bolt for hanging a swag

lamp or a plant from ceiling.

(iii) Screw Eye has a ring shaped end. Use it alone by fitting objects

through the ring.

(iv) Hook and Eye has a hook attached to a screw eye that screws into

a gate or door. The hook fits into another screw eye to keep the gate or

door closed or open.

(v) Rope Hook comes in various designs. These are general purpose

hook with two or four holes in the flat stem for screws. A porch-swing hook,

which is screwed into the porch roof, a hammock hook with a plate to secure

38

it to flat surface.

(vi) Self-adhesive Hook made of plastic and meant for light weight

objects. To install, wipe the surface clean, remove lining paper and press

hook in place.

(vii) Coat Hook may have one, two or more hooks in various directions

for hanging coats and hats.

(viii) Picture Hook is nailed into a wall. A wire is attached to the back of

picture frame and hanged on to the hook.

(ix) Heavy-duty Hook is for hanging objects in a garage or workshop

for items like bicycles and spare parts.

HASP

Hasp is a slotted hinged metal plate that forms part of a fastening for a

door or lid and is fitted over a metal loop and secured by a pin or

padlock.

HINGES

A hinge often has two leaves held together with a pivot pin inside knuckles or barrel. Most cabinet and

house doo hinges can be used either left or right handed doors. Hinges can be surface mounted (with

leaves slightly raised), but the leaves create a gap between the door and frame when the door is closed.

The three basic types of hinges are:

(i) Butt Hinges

Most butt hinges have a non-removable fixed pin. They are

suitable foran exterior door where the barrel is exposed outside;

to remove door, the hinge must be unscrewed. Some have

deattachable pin to allow for door removal without unscrewing the hinge.

(ii) Flush Hinges

This hinge is normally used for a light weight door and is surface

mounted but does not create large gaps. To install, screw the small

leaf to door and large leaf to the frame; when closed, the small leaf

fits into the large one.

(iii) Tee Hinges

Tee hinges comes in large heavy duty sizes for doors, gates ,

boxes and chests.

Leaf Pin

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Working with Non-Metals Solid non-metals are usually dull, brittle and non-conductors of heat and electricity. Some examples of

non-metals are wood, plastic, rubber, glass and ceramics. Some of the non-metals that are discussed in

this section are PVC, ceramics and manufactured boards.

Polyvinyl Chloride (PVC)

PVC pipe is the most used plastic piping material. PVC pipe is manufactured by extrusion in a variety

of sizes and dimensions. PVC pipe is made to conform to various standards for both pressure and non-

pressure applications. PVC piping is used in Drain-waste-vent (DWV), sewers, water service lines,

irrigation and various industrial installations. It can be used under ground or above ground in

buildings. PVC materials are resistant to many ordinary chemicals such as acids, bases, salts and

oxidants. Since PVC piping system components are manufactured in a variety of colors, identification

of application is easy.

A common color scheme (although not universal) is:

White for Drain-waste-vent (DWV) and low pressure applications.

White, blue, and dark grey for cold water piping.

Green for sewer service.

Dark grey for industrial pressure applications.

Common Fittings

90˚ ELL

These fittings are designed to turn the flow of a liquid at a 90-degree angle.

Often in home plumbing, for example, the plumbing needs to turn to flow

where it is needed to avoid existing structures in the home or access outside

lines. This 90-degree turn improves the function and design options for the

system.

45˚ ELBOWS

PVC 45° Elbow joins two pieces of the same size pressure pipe at

an angle of 45°. These are used to re-direct the pipeline and to assist in

turning corners.

TEE

Tee fitting is a necessity in any PVC structure design. There are total of

three ‗ports‘; with all going in three different directions along the same

plane.

PVC Tee is used to create simple wall structures and three-point

connections in plumbing.

Cross

PVC cross fittings are not quite as common as other fittings, but they are

designed for use when joining four pipe sections or dividing flow in

different directions. This could be done in plumbing and irrigation

systems.

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Threaded Male & Female Connectors

Female adapters are used to add a female threaded pipe connection on a

solvent welded pipe.

Male adapters are used to add a male threaded pipe connection to a

solvent weld pipe section.

Connector

This connector is used to join two pipes together normally for

extension. The two pipes to be connected together are glued at ends to

be joined into the either ends of the connector and cannot be taken apart.

End Cap

Sometimes a PVC pipe system will end with an opening that

does not need to be connected to another pipe. Perhaps the system

is being left open for expansion, or perhaps the end is left open to

provide access to the system when needed. When this occurs, the

flow needs to be stopped, and an end a cap simply stops the flow.

Ceramics

Ceramics are classified as inorganic and non-metallic

materials that are essential to our daily lifestyle.

Ceramics are generally made by taking mixtures of

clay, earthen elements, powders, and water and

shaping them into desired forms that are normally

used when materials that can withstand high

temperature are required. As a result, they are used to

make pottery, bricks, tiles, cements, and glass.

Ceramics are also used at many places in gas turbine

engines. Bio-ceramics are used as dental implants

and synthetic bones.

Manufactured Boards

Manufactured boards are valuable materials in their own right, with an important part to play

alongside with solid timber, example plywood and core-board. They are available in large, stable,

standard sheets (1525mmX1525mm, 1220mmX2240mm), of uniform thickness and quality.

Plywood

Plywood is the name given to panels or sheets

constructed by gluing together three or more

layers of this wood called ‗veneers‘ or ‗plies‘ so

that the grain of one layer runs at right angles to

that of an adjacent layer.

Uses of Plywood

The scope and use of plywood is too wide to

explain in detail. However, some common uses of

plywood are:

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Furniture Manufacture: In carcass construction, it is glued to a framework. It is also used as

backing for cabinets, drawer bottoms, radio cabinets, door panels and chair backs and bottoms.

Building Works: In building works it is used for panelling, flush doors and built-in fitments.

Exterior grades are used for wall sheathing and concrete form-work.

Boat Building: It used in crafts and yachts of all sizes. Special waterproof marine grade

plywood is manufactured to resist water indefinitely.

Aircraft Construction: The strength of the plywood combined with its light weight makes it

ideal for this type of work, light gliders and sail planes.

Other Uses: It is also used in coachwork, railway carriages and boxes.

Core-board

Core board is a manufactured board with a wood fibre

or wood chip centre and bonded veneer faces on both

sides. It is very strong, lightweight, and easily cut

material used for the mounting of photographic prints,

as backing in picture framing, in 3D design, and in

painting.

Working with Metals A metal is a material that is typically hard, opaque, shiny, and

has good electrical and thermal conductivity. Some examples of

metals are aluminium, copper, iron, lead, zinc, tin, silver and

gold.

Mechanical Properties

Mechanical Properties refers to the behaviour of material when external forces are applied.

Some of the mechanical properties are:

1. Hardness

Hardness refers to the ability of a metal to resist scratch, penetration, cutting action, or permanent

distortion. Hardness may be increased by working the metal and, in the case of steel and aluminium

alloys, by heat treatment and cold-working.

Brittleness

Brittleness is the property of a metal that allows little bending or deformation without shattering. In

other words, brittleness is the ability to break or crack without changing shape. Since structural metals

are often subjected to shock loads, brittleness is not a very desirable property. Cast iron, cast

aluminium, and very hard steel are brittle metals.

Malleability

A metal that can be hammered, rolled, or pressed into various shapes without cracking or breaking is

said to be malleable. This property is necessary in sheet metal that is to be worked into curved shapes.

Copper is one example of a malleable metal.

42

Ductility

Ductility is the property of a metal that permits it to be permanently drawn, bent, or twisted into thin

lengths without breaking. This property is essential for metals used in making wire and tubing. Ductile

metals are greatly preferred for aircraft use because of their ease of forming and resistance to failure

under shock loads. Ductility is similar to malleability.

Toughness

A material that possesses toughness will withstand tearing or shearing and may be stretched or

otherwise deformed without breaking. Toughness is a desirable property in aircraft metals.

Finishing of Materials The last stage in the construction process is applying a perfect finish. The visual appeal of the material

is one of the attractions of woodworking and metalworking.

Painting is one of the common methods used in finishing materials. However, different types of

finishing are used on different types of materials.

Wood Finishing

Finishes serve to prevent wood absorbing moisture, protect against decay and enhance appearance.

Basic preparation is needed before any type of finish is applied to wood.

Staining

Stain can be used to match different components in construction and to

achieve attractive contrasts of tone. Wood stains ready-mixed are

available in hardware stores. The stain that is needed to be used should

always be tested on an offcut of the same piece of wood.

Varnishing

One of the most popular varnishes used is polyurethane since it is easier to apply and produces clearer

result.

Painting

Paint provides a protective colouring for both indoor and outside

softwood. Sharp corners should be made slightly smooth with

glass paper. First seal with a primer then apply undercoat, rubbing

down between coats with fine glass paper and then apply final

coat.

Lacquers

Several coats of Lacquers is needed for an effective finish since it is

thinner compared to varnish. Spray application is used for best

results but not always used.

43

Wax

To suit different wood types, furniture wax can be obtained ready

coloured. Over some time the wax applied on the material will form

deep lustrous colour within the wood surface.

Oil

Since oil is natural and waterproof, it provides a perfect finish for

outdoor furniture.

Metal Finishing

To protect metal from rust, coat it with Vaseline or light grease.

Oil Finishing

Steel can be either dipped in machine oil burnt into the metal or the

metal can be heated to dull red and quenched in oil.

Painting

For painting metal, the surface must be thoroughly cleaned and then washed with hot water and

detergent. Metal primer is suitable for most metals. For maximum protection an oil-based undercoat

and top coat should also be used.

Plastic Coating

The most suitable method is to dip pre-heated metal into a tank of liquefied thermoplastic such as

polythene, PVC or nylon. This is done to prevent metal from corrosion and to provide electrical

insulation.

Electroplating

Thin layer of metal is deposited on the surface of the metal to be used. Some examples are chromium

plating on steel, silver and gold plating on jewellery and simple copper plating.

Sandstones

Sandstone is a sedimentary rock, typically formed from the most

common minerals in the earth‘s crust. This type of stone can come

in many different colours, from yellow, orange and brown to red,

pink and black. Sandstone has been a popular building material for

thousands of years, used by ancient civilizations for construction,

as well as for housewares.

Common uses of sandstone

Sandstone is a popular choice for both flooring and walls, indoors

and outdoors. It‘s also commonly used as a decorative stone, or

carved into items like bookends, coasters and

paperweights. Sandstone is often found in backyards and patios,

whether as pillars, arches, fountains or simple arts & crafts.

44

Common finishes of sandstone

Along with slate, sandstone often comes with a natural cleft surface finishing. However, there are

many options when it comes to sandstone finishes.

One popular choice is a honed finish. This finish is created by grinding and sanding, resulting in a

smooth surface that is not as glossy as a polished finish. This is a good choice for high-traffic areas

where low maintenance is desired. For instance, while a polished finish might wear off in a busy

walkway, a honed finish will keep its smooth surface.

The Stone Oil has excellent penetration properties and therefore

ensures a hard-wearing, dirt and water resistant surface. The

Stone Oil is a pre-polish sealer formulated to give an aged

appearance to natural stone and enhances the natural structure of

the floor. Stone Oil may be used indoors on all unfinished, open

structured floors of stone, quarry tiles and marble.

Sharpening Hand Tools Planes and chisels cut well only if they are sharp. Two kinds of operations are done to sharpen these

tools. Grinding reshapes the cutting edge of tool. It should be done only when the tool needs a new

bevel or when the edge of the cutter is nicked. Otherwise, honing-sharpening the tip of the cutting

edge is enough.

Grinding plane blade

(i) Check the cutting edge of the blade under light. If it reflects

light, sharpening is needed.

(ii) Hold a try square on the edge of the blade and check to see

if the cutting edge is square with the sides. If it does not,

grind off the old edge at right angles to the sides till the

edge is straightened.

(iii) If you are grinding the blade ―freehand‖, grind as close as possible to the same angle each time

the blade is returned to the wheel.

(iv) Continue to grind the blade until a wire edge appears.

Sharpening the Blade

(i) Apply few drops of mineral oil to the face of the oilstone.

(ii) Place the blade at an angle of about 30 to 35 degrees to the

stone.

(iii) To hone the edge, move the blade back and forth in a

straight line.

(iv) Now turn the blade over and place it flat against the stone.

Move it back and forth to remove the wire edge.

(v) To test for sharpness, try slicing a piece of paper with the blade.

45

Questions

1. What kind of saw must be used to cut across grain and with the grain?

2. Why should planes and chisels be kept sharp?

3. What happens if you bore a hole through a piece of wood from one side and don‘t

support it with scrap stock on the other side?

4. What are two kinds of hardware used in constructing projects?

5. Name and describe two types of hinges used in joinery.

Activities

1. Use a magnifying glass to examine the teeth of the saws in your workshop. Which are

crosscut saws? Which are rip saws?

2. Check the plane blades and chisels in your workshop. Do any of them need honing? Do any

need both grinding and honing?

3. Demonstrate how to install a bit in the brace.

4. Demonstrate how to mark a door and frame for location of hinges.

46

GEOMETRICAL DRAWINGS

The word construction in geometry has a very specific meaning: the drawing of geometric items such

as lines and circles using only compasses and straightedge or ruler. In the process of preparing a

drawing there will be many occasions when it will be necessary to utilize more than one geometrical

construction. These construction techniques will be helpful in solving problems.

2D DRAWINGS

ORTHOGRAPHIC PROJECTION

Types of Orthographic Drawing (Projection)

1. First Angle Projection

2. Third Angle Projection

FIRST ANGLE ORTHOGRAPHIC PROJECTION

First angle projection is a method of creating two-dimensional (2D)

drawings out of a three-dimensional (3D) object. The views are

drawn as if a torch is shined on the object and a shadow is

projected on the wall behind the object. This is important

information for the layperson when interpreting drawings.

Chapter 5

After studying this chapter students should be able to:

Recognize and develop skills in pictorial

projection.

Acquire added concepts in pictorial projection.

Outcome

Introduction

47

Views used in orthographic drawing:

View looking from the front - ELEVATION

View looking from the top - PLAN

View looking from the side - END ELEVATION

In basic orthographic drawing it is important to know that, the views are drawn on the principal planes of

projection.

Principal Plane of Projection

It consists of two intersecting planes namely the VERTICAL PLANE (VP) and the HORIZONTAL

PLANE(HP).

The illustration below shows the relationship between the principal planes of projection in the first angle of the

intersecting planes.

The illustration below shows the unfolded position of the principal planes showing the proper arrangement of

the views. It must be noted that, even though the three views are drawn separately, there is a very strong

relationship between them. The table below shows the relationship between the three views.

Application of orthographic drawing:

This method of drawing as mentioned earlier is the most effective way of communicating ideas in drawing and

it is mostly used by Architect, Engineers, Surveyors, Civil Engineers

VERTICAL PLANE

HORIZONTAL

PLANE

VIEW VISIBLE

MEASUREMENT

1. Elevation (Front) Length & Height

2. Plan (Top) Length & Width

3. End Elevation (Side) Width & Height

Width

Widt

h

Height

Height

Length

48

Example: 1 Example: 2

First angle projection is a method of creating a 2D drawing of a 3D object. This is important information for

the person interpreting the drawing because if you examine the diagram below you will note that in first angle

orthographic projection:

Relationship of the principal planes and the types of orthographic projection (drawing)

Fig.1 Fig. 2

Unfold position of the principal planes showing the proper arrangement of views.

49

Fig.3 In real presentation of orthographic drawing the 4 corner planes are omitted.

Rules of first angle orthographic projection

Draw the front first

Directly below the front, draw the plan

For the end elevation, things you see from the right draw it on the left and things you see from the left

draw it on the right

THIRD ANGLE ORTHOGRAPHIC PROJECTION

Third Angle – In third angle the principal planes are seen as transparent plane as shown in fig.4

Fig. 4

50

Rules of third angle projection

Draw the front first

Directly above the front draw the plan

For the end elevation, things you see from the right draw it on the right, things you see from the left

draw it on the left.

You must have seen the arrangement of views in both projections as shown earlier in this chapter. Different

positioning of views reflect the different positioning of the planes in both the projection- (first angle and third

angle)

Fig. 5 Conventional symbols of the two projections

Fig.5 (a) and (b) shows the projection conventional symbols used in orthographic drawing to describe the types

of projection used.

EXERCISES

Draw three views of each object in the positions indicated scale

51

A. For each shaped block 1 and 2 draw the orthographic views in 1st angle projection using the measurement

provided on the drawing. Label the views correctly using guide lines.

1 2

PICTORIAL DRAWING

3D DRAWINGS

PICTORIAL DRAWING

Pictorial sketches often are more readily made and more clearly understood than are front, top, and

side views of an object. Pictorial drawings, sketched freehand or made with drawing instruments, are

frequently used by engineers and architect to convey ideas to their assistants and clients.

In making a pictorial drawing, the viewing direction that shows the object and its details to the best

advantage is chosen. Several types of pictorial views can be sketched, or drawn. This can be isometric

view, oblique view or perspective view.

A. ISOMETRIC DRAWING

Isometric means "equal measurement". The true dimension of the object is used to construct the

drawing. You get the true dimension from either orthographic views or by measuring the object.

Because of the ease of using actual measurements to create the isometric image, it has become the

industry standard for parts manuals, technical proposals, illustrations and maintenance publications.

The height of the object is measured along vertical lines. The

width and depth of the object are measured along the 30

degree to the horizontal plane.

ISOMETRIC OBLIQUE PERSPECTIVE

52

Step 1

Isometric sketches begin with defining isometric axes,

three lines, one vertical and two drawn at 30° from the

horizontal.

Step 2

Three lines of the isometric axes represent the three primary

dimensions of the object: width, height, and depth.

Step 3 Step 4

Draw the rest of the isometric block. Draw the font face of the isometric block.

Step 5

Add details to the block starting from the front face. Then add details to the other faces.

Step 6

Darken all visible lines to complete the isometric sketch. (make sure

that construction lines are light)

53

Note: In isometric sketch/drawing, hidden lines are omitted unless they are absolutely necessary to

completely describe the object.

Circles in Isometric

A circle in a orthographic projection will appear as an ellipse in an isometric drawing.Instead of actual

ellipses often approximate ellipses are drawn for isometric drawing. Four-centre ellipses are used to

approximate ellipses on isometric planes.

• Draw the isometric centre lines of the circle. Using the centre lines, draw an isometric square

with sides equal to the diameter of the circle.

• From the near corners of the box, draw two large arcs with radius R, using the two red points

as centres.

• Draw the two smaller arcs with radius r, using two green points as centres.

Example:

B. OBLIQUE DRAWING

The oblique method of drawing is the simplest method that can

be used to draw objects pictorially. Oblique drawings of objects are

easily recognized because surfaces directly in front of the observer are

viewed orthographically.

In Cavalier Oblique drawings, all lines (including receding lines) are made to their true length.

In Cabinet Oblique drawings, the receding lines are shortened by ½ their true length.

Circles in oblique

54

In an oblique drawing, a circle on the surface parallel to the plane of projection will appear as a circle.

A circle on any other surface will appear as an ellipse.

C. PERSPECTIVE DRAWING

Perspective drawing is used to represent an object as it would appear to the eye when viewed from one

particular position. A perspective drawing shows a view like a picture taken with a camera It may be

used in working drawings where a more realistic representation or artistic effect is required than that

obtained by means of isometric or oblique drawing.

One point Perspective

In one point perspective drawing, depth is added to a

drawing by taking lines to a single vanishing point. One

vanishing point is typically used for roads, railway tracks,

hallways, or buildings viewed so that the front is directly

facing the viewer.

Orientation the object so that a principal face is parallel to the viewing plane (or in the picture plane.)

The other principal face is perpendicular to the viewing plane and its lines converge to a single

vanishing point.

55

Steps in one point perspective:

First, we draw a crate that represents the height, length and width of the object that we

want to draw.

Extra lines are then drawn softly inside the crate until the shape of our object is

complete. We call these feint lines construction lines.

The outline of the object is then drawn darker over the feint construction lines.

Construction lines may be rubbed out using an eraser or if they are very feint, they may

be left.

Finally the drawing may be rendered by adding light, shade and colour.

Examples of one point perspective drawing

Two point perspective

In two point perspective drawing, we imagine two

vanishing points. The two top corners of the page may

be used for most purposes. Two-point perspective can

be used to draw the same objects as one-point

perspective, rotated: looking at the corner of a house,

or looking at two forked roads shrink into the distance,

for example. One point represents one set of parallel

lines; the other point represents the other. Looking at a

house from the corner, one wall would recede towards

one vanishing point; the other wall would recede

towards the opposite vanishing point.

56

Steps in Two Point Perspective

All the lines that are drawn towards

the left are drawn to the left

vanishing point.

All the lines that are drawn towards

the right are drawn to the right

vanishing point.

Vertical lines stay vertical.

We normally draw a crate first that

represents the height, length and width of the object that we want to draw.

Extra lines are then drawn inside the crate until the shape of our object is drawn faintly.

The outline of the object is then drawn darker over the feint construction lines.

The construction lines may be rubbed out using an eraser or if they are very feint, they may be

left. Finally the drawing may be rendered by adding light, shade and colour.

Examples of two point perspective drawing:

ACTIVITY

A. The drawings below show the orthographic views of shaped blocks. Use the measurements

directly from the drawing to draw the isometric and oblique view of the blocks using the

instruments.

B. Draw free hand sketches of the blocks in one and two point perspective.

1. 2.

57

3.

4.

B. The diagrams given below shows the orthographic views of shaped blocks. Use the

measurements given in the diagram to draw the oblique and isometric views of the blocks.

PRISMS AND CYLINDERS

In technical drawing, objects are usually composed of an arrangement of geometrical solids, either in

one peace or fastened together. An understanding of the geometrical solids is therefore essential before

objects can be satisfactorily represented in technical drawing.

The axis of a solid is the imaginary line drawn from the centre of the top to the centre of the base of

the solid. When the axis is at right angle to the base, it is called a right solid, and when the axis is

inclined to the base or end of a solid it is called an oblique solid. When the edges of the base or end of

a solid are equal, it is called regular.

A cube is a solid contained by six equal squares. The axis is the imaginary line joining the centres of

the opposite sides. A cube can thus have three axes.

A right regular prism is a solid whose sides consist of equal rectangles, ad two equal ends. It is

named by its ends. The axis is the line joining the centres of the ends. The axis is the line joining the

centres of the ends. Examples of right regular prisms are: square prism, equilateral triangular prism,

right pentagonal prism, etc. ( A rectangular prism is not a regular prism).

A right regular pyramid is a solid whose sides consist of equal isosceles triangles meeting at a point

above the base called the apex. Pyramids are named from their bases. The axis is the line joining the

apex and the centre of the base.

1.

2.

58

A tetrahedron is an equilateral triangular pyramid contained by four equilateral triangles.

A right cylinder is a solid generated by the revolution of a rectangle about one of its fixed sides. The

fixed side becomes the axis, that is, the line joining the centres of the circular ends.

A right cone is a solid generated by the revolution of a right-angled triangle about its perpendicular.

The perpendicular then becomes the axis, i.e. the line joining the apex to the centre of the base.

A sphere is a solid generated by the revolution of a semi-circle about its diameter.

Frustum When the upper portion of the pyramid or a cone has been cut away, the remaining portion is

called a frustum, and the solid is said to be truncated.

Types of prisms:

Rectangular prism

Rectangular Prism: A Prism with rectangular bases is a Rectangular

Prism. It has 4 lateral faces and 2 rectangular base and top.

A rectangular prism is a 3-dimensional object, which has as many as six

faces. It is a solid material and all the faces are rectangular. One more

reason because of which it is regarded as a prism is that it has the same

cross section along a length.

Hexagonal prism

A hexagon has six sides and a hexagonal prism has six sides and two bases. It

is mostly considered as a space-filling polyhedron. Moreover, the regular right

hexagonal prism has a definite formula to calculate the surface area and

volume.

Triangular prism

Two triangular bases and three rectangular sides make a triangular prism. It

falls in the category of a tetrahedron. It has 3 lateral faces and 2 triangular

bases.

THE GEOMETRICAL SOLIDS

Pyramids

In technical drawing, objects are

usually composed of an arrangement of

geometrical solids, either in one peace

or fastened together. An understanding

of the geometrical solids is therefore

essential before objects can be

satisfactorily represented in technical

drawing.

Square Based Pyramid Hexagonal Based Pyramid

Pentagonal Based Pyramid Triangular Based Pyramid

59

The axis of a solid is the imaginary line drawn from the centre of the top to the centre of the base of

the solid. When the axis is at right angle to the base, it is called a right solid, and when the axis is

inclined to the base or end of a solid it is called an oblique solid. When the edges of the base or end of

a solid are equal, it is called regular.

A cube is a solid contained by six equal squares. The axis is the imaginary line joining the centres of

the opposite sides. A cube can thus have three axes.

A right regular prism is a solid whose sides consist of equal rectangles, ad two equal ends. It is

named by its ends. The axis is the line joining the centres of the ends. The axis is the line joining the

centres of the ends. Examples of right regular prisms are: square prism, equilateral triangular prism,

right pentagonal prism, etc. (A rectangular prism is not a regular prism).

Development of a Prism

Parallel Line Development

To develop the surface of a rectangular prism

(a)Draw the plan and elevation of the prism to scale.

(b) Number the edges as shown.

(c) Set out the stretch out. This is the perimeter of the prism measured off the plan.

(d) Project the height of the prism parallel to the stretch out line.

(e) Draw the vertical fold lines at points 2,3 and 4.

(f) The prism ends are added by revolving the lengths 2-3 and 1-4.

Note: Final outlines should be firm. Fold lines should be light continuous lines.

60

Development of a Cylinder

1. Draw the plan and elevation. The stretch out for the curved surface of the cylinder should equal

the circumference of the cylinder.

2. For drawing purposes the cylinder is thought of as many sided prism. We usually divide the

plan into 12 divisions. The length of the stretch out is obtained by stepping off the same

number of equal spaces (12) along the stretch out line.

3. The height of the development will be the height taken from the elevation. Ends of the cylinder

should be cut out as separate parts.

61

Development of a Cone Radial line Construction may be used to develop the curved surface of a cone.

Fig A1. These illustrate the construction of a cone.

Fig A2. The intersection of a cone by a cutting plane D-D

Note. The intersection of the plane and cone elements must be projected into the true length

edges.

.

Development of a Pyramid

Fig.1 shows a square based pyramid in plan andelevation. The true length of pyramid edge 0-

3 is not shown in these views and must be constructed before the radial line development can

be started.

Fig.1 shows the construction. Line 0-3 is revolved in the plan view and projected into the

elevation. The true length lateral edge 0-3 is the radius for the construction.

Fig.2 To complete the development of the pyramid, use dividers to set off the base edges 1-

2,2-3,3-4 and 4-1 from the plan view.

62

Fig.3. The pyramid is intersected by the horizontal cutting plane A-A. If you look at the

pictorial view the effect of the intersection is to remove the apex of the pyramid. The pyramid

is then termed as truncated pyramid.

Fig.4. The construction of pyramid in a different layout. The true length is edge 0-2 as its

plan is parallel to the reference line. Therefore, it does not require rebatement method in

finding the true length.

To complete the development the cutting plane is extended to point A in the true length line.

True length O-a can then be transferred to the development.

63

SURFACE DEVELOPMENT

The development of an object is made by laying out the true shape surfaces of the object on a plane.

Fig A shows the development of a square prism. There are six surfaces to lay out in sequence.

Applications. Practical applications involving development are frequently used in sheet metal work

and engineering. Common examples are metal cans, drums, tool boxes, heating ducts. Can you name

any more?

Development of Prisms and Cylinders Intersected by Cutting Planes

64

Radial Line Development

Figs A and B. Pyramids and cones are developed by using the radical line construction.

The fold lines in the case of the pyramid radiate about the apex. The elements of the cone radiate

about the apex.

Fig A. Illustrates the laying out of a square pyramid to provide the true shape of the four triangular

sides and the square base.

Fig B. illustrates the laying out of a cone to give the true shape of the curved surface. Notice how the

cone is divided into equally spaced straight line elements. Remember the construction for the

development of a cylinder? Reference: 11-4.

The small pictorial views of the pyramid and the cone show the names of the various parts.

65

Development of a Pyramid

Fig 1 shows a rectangular pyramid in plan and elevation. The true length

of pyramid edge 0 -1 is not shown in these views and must be

constructed before the radial line development can be started.

Fig 1 shows the construction. Line 0-1 is revolved in the plan view and

projected into the elevation. The true length lateral edge 0-1 is the radius

for the construction.

Fig 2. To complete the development of the pyramid use dividers to set

off the base edges 1-2, 2-3, 3-4 and 4-1 from the plan view.

Fig 3. The pyramid is intersected by the horizontal cutting plane A-A. If you look at the pictorial view

the effect of the intersection is to remove the apex of the pyramid. The pyramid is then termed a

truncated pyramid.

To complete the development the cutting plane is extended to point A in the true length line. True

length 0-a can then be transferred to the development

66

Development of a Cone

Radial line construction may be used todevelop the curved surface of a cone.

Figs Al andA2. These illustrate the construction for a cone.

Fig A3. The intersection of the cone by a cutting plane D - D.

Note. The intersection of the plane and cone elements must be projected into the true length edges.

Problems 1 and 2

Construct the development of the curved surfaces of the truncated cones.

ACTIVITY

1. Six geometrical solids are illustrated in Fig.1. (a) Write down the correct name for

each solid. (b) Name the development method used for each.

2. Name the various parts of the pyramid shown in Fig2.

3. Fig 3. (a) Construct the true length of edge 0-1. (b) Draw the development of the

surfaces.

4. Fig 4. Draw the development of the sides of the prism. The prism is shown intersected

by the cutting plane D-D.

67

5. Fig 5. Draw the development of the cylinder as described in Fig 4.

6. Fig 6. Draw the development of the pyramid as described in Fig 4.

7. Fig 7. Draw the development of the cone as described in Fig 4.

8. Fig 8. Construct the complete development of the model aircraft fuel tank.

9. Fig 9. Develop as described in Fig 8.

10. What is meant by the term ―development of the surfaces of an object?‖ (b) What

practical has the development construction?

11. Construct the development of a carton to contain six new drawing pencils.

Chapter 6

68

JOINTS AND PROCESSES

Dimensioning of joints is a very difficult and complex operation which precedes breach

of the construction and product deterioration. Stiffness and strength of structural furniture

elements related to and furniture itself depends mainly on the material properties joining

(element dimensions, material type, etc..), the type mechanical connectors and the way of its

shoulder application. It is often found in furniture construction single shear steel-to-timber

joints,

they represent the connection fittings, such as allowing the movement of furniture parts with

screws. From the size and purpose of fittings depends on size of screws for fixing fitting. Our

research task is ascertaining the mechanical properties of single shear steel-to-timber joints

with

wood screws.

WOODWORK JOINTS

Common Mortise and Tenon joint

This is one of the most common woodworking joints and the

strongest as well. The two parts are the tenon which has a

projection on the end and the mortise, the hole in the other

part into which the tenon fits. The width of the tenon is

usually 1/3rd the width of the board.

Constructing the joint:

Step 1 - Preparation of timber

After studying this chapter students should be able to:

Identify common joints

State the use of common joints in wood and

metals

Able to construct these joints

Outcome

s

Introduction

69

(a) Prepare the timber to the required sizes using the FEWTEL (Face Side, Face Edge,

Gauge for Width, Gauge for Thickness, Shoot the End, Measure the required Length)

method.

Step 2 - Marking out

(In the following steps, the piece with the mortise is

"piece A" and the one with the tenon is "piece B".)

(a) Mark out the length of the tenon on piece B.

Allow 3 mm waste in the length and make square

lines all around with a try square and pencil (Fig. 2).

(b) Take piece A and mark out the position of the mortise

on the face edge and make square lines on the edges

on both sides with the try square (Fig. 3).

(c) Set the marking gauge to the width of the tenon and

mark the lines around piece B at the width. Mark the

waste with small crosses (Fig. 4).

(d) Use the same setting to mark both faces of piece A and

use a try square and (already smoothed) piece B to mark the remaining two lines for

the width of the mortise (Fig. 5). Mark the waste with a small cross.

Note: If the marking gauge has two pins, set each at its correct measurement and mark both

lines at one. If not, mark with the first setting on all the members, then change the setting and

mark the other measurement on all the members.

(e) Always mark from the face edge. Check the marking by setting piece B against the

marks on piece A to see if they fit. Piece B must be smoothed first.

Step 3 - Cutting the mortise

Fig. 2 Fig. 3

Fig.

4

Fig.

5

Fig. 6

Fig. 7

Fig. 1

Mortise Tenon

70

(a) Bore out most of the waste, using a brace bit (Fig. 6). Clamp a piece of wood to the

underside to prevent splintering and damage to the bench.

(b) Chop out the remaining waste with a mortise chisel, chiseling halfway through from

both sides. Leave about 2 mm extra waste on all sides to prevent damage to the sides.

Keep the cutting edge of the chisel across the grain.

(c) Carefully chop out the rest of the mortise up to the lines (Fig. 7). Keep the bevel of

the chisel towards the inside of the mortise. Do not use the

mallet.

Step 4 - Cutting the tenon

(a) Rip the sides of the tenon sawing on the waste side of the line

(Fig. 8).

(b) Cut in stages as shown in Fig. 11, a, b, c, &d).

(c) Carefully saw the shoulders, making sure to hold the saw straight. Keep on the waste side

of the line (Figs. 9 & 10).

Step 5 - Assembling the joint

(a) Check the fit of the members. The tenon should fit tightly into the mortise without

splitting the mortised piece. There should be no gap between the shoulders of the

Fig. 9 Fig.

10

Fig. 8

Fig. 11a Fig. 11b Fig. 11 c Fig.11d

71

tenon and the mortised member. Don't force the members together. If they don't fit,

find the problem and correct it.

(b) Clean up the inside of the joint where it can't be reached after assembly with a

smoothing plane. (Remember that the tenon should be smoothed before using it to

mark out.)

(c) Assemble the joint.

(d) Plane off the waste end of the tenon, clean up all sides and edges with the smoothing

plane.

Corner Locked or Box Pin joint

The corner locked joint is similar to the mortise and

tenon joint. It is an angled joint with a series of tenons on

one member which correspond to slots on the other

member (Fig. 1). The resulting joint is strong because it

can be nailed from two sides, and the interlocking tenons

and slots also help hold the pieces together.

Constructing the joint:

Step 1 - Preparation of the timber

(a) Prepare the timber using the FEWTEL (Face Side, Face Edge, Gauge for Width,

Gauge for Thickness, Shoot the End, Measure the required Length) method.

Note:If the members are to be used for a box where the external appearance is important, the

face sides should be outside. In most cases the face edges are kept upwards.

Step 2. Marking out

(a) Mark out the position of the tenors and slots by gauging or squaring lines at the

corners on the ends of the pieces: on piece A the depth should be equal to the

thickness of piece B (Fig. 2); while on piece B the depth should be equal to the

thickness of piece A (Fig. 3). Allow 2 mm waste for cleaning up after assembly.

(b) Mark out the shape of the tenons on piece B. Keep all tenons the same size.

Fig. 1

Fig. 4

Fig. 2

7&

Fig. 3

72

(c) Immediately mark the waste between the tenons with crosses

(Fig. 4).

Step 3 - Cutting the tenons

(a) Rip the sides of the tenons down to the gauge line (Fig. 5).

Saw on the waste side of the line.

(b) Chop out the waste by chiseling alternately vertically and then at an angle, making

"V" cuts halfway through from each side. (Figs. 6, 7, & 8).

Step 4 - Cutting the slots

(a) Place piece B (with the tenons) over the end of piece A, with the face

side towards the outside as indicated in Fig. 9. Mark the shape of the

tenons onto piece A with a pencil (Fig. 9).

(b) Square the sides of the slots down both sides. Mark the waste with

small crosses (Fig.10).

(c) Rip the sides of the slots, sawing on the waste side of

the line.

(d) Chop out the waste from the slots, chiseling from both sides as explained in the

previous step (Fig. 11).

Step 5 - Assembling the joint

(a) Clean up the inside faces of the joint.

(b) Assemble the joint with glue and nails.

(c) When the glue is dry, clean up the waste off the tenons and slots with a smoothing

plane.

(d) Make sure the nails are punched well below the surface to prevent damage to the sole

of the plane.

(e) Clean up the outside faces and edges with a smoothing plane.

Fig. 11

Fig. 10

Fig.

5

F

i

g

.

8

F

i

g

.

6

F

i

g

.

7

Fig. 9

73

FRAMING JOINTS

Framing joints are those used in frame-like construct ions. The members are usually

constructed with their edges at right angles to each other; in contrast to the angle joints where

the sides forms the right angle.

Halved joints

Halved joints are a type of framing joint. The name is applied to joints where the pieces of

timber which meet or cross each other are halved. At the joint, each piece is ½ the thickness

of the rest of the piece. The result is an assembled flushed joint, in which the surfaces of both

pieces are flushed.

Halved joints are used for constructing simple frames.

In the building industry, there are four different kinds of halved joints. The discussion here

will focus on the description and construction of the "tee-halved joint". Similarly, the

procedures can be applied for the other halved joints.

74

Tee-Halving Joint

The tee-halved joint consists of a pin (a) on the end of one piece

which fits into a socket (b) in the other piece (Fig. 1).

The pin is half the thickness of the timber, and the depth of the socket

equals the thickness of the pin. The shoulder of the pin (c) fits against

the face edge of the socket (Fig. 1).

Constructing the joint:

Step 1 - Preparation of timber

(a) Prepare the timber using the FEWTEL (Face Side, Face Edge, Gauge for Width,

Gauge for Thickness, Shoot the End, Measure the required Length) method.

Step 2 - Marking out

(b) Mark the length of the pin by placing the socket piece on top of it and marking at the

width. A small amount of waste can be left on the end of the pin, to be planed off after

the joint is assembled.

(c) Make lines square at the shoulder of the pin, drawing them

across the side and halfway down the edges, with a try square

and pencil (Fig. 2). Mark the waste.

(d) Mark the position of the socket, using the piece with the pin as a guide. Smooth the

pin before using it to mark the socket.

(e) Square the lines across the side and halfway down the edges with a try square. Mark

the waste (Fig. 3).

(f) Gauge the thickness of the pin around its edges and mark the waste (Fig. 2).

(g) With the same setting, gauge the depth of the socket on both edges and mark the

waste (Fig. 3). Both pin and socket should be gauged from the

face side.

(h) Place the pin over the position of the socket and check the

fitting (Fig. 4).

Fig. 1

Fig. 2

Fig. 4

75

Step 3 - Cutting the pin

(a) Rip the thickness of the pin. Cut in stages as shown in Fig. 5, a through d. Take care

to keep on the waste side of the line.

(b) Saw the shoulder of the pin, keeping

on the waste side of the line (Fig. 6).

Step 4 - Cutting the socket

(a) Saw down to the gauge lines of the socket, keeping on the waste side of the lines (Fig.

7).

(b) Chisel out the waste, chiseling halfway through from both edges (Figs. 8 & 9).

(c) Test the flatness of the socket with the blade of the try square.

Step 5 - Assembling the joint

(a) Clean up the inside edges with a smoothing plane.

(b) Assemble the joint with glue and nails.

(c) When the joint is dry, plane off the waste of the pin.

(d) Clean up all sides and edges with the smoothing plane.

Corner-Halved Joint

Another halved joint is the corner-halved joint (Fig. 1). It is used

where the pieces meet at their ends to form a corner. The sequence of

operations to construct this joint is similar to the one for the tee-

halved joint, except that instead of a pin and a socket, two pins have

to be marked and cut.

Fig. 5

a b

c

d

Fig. 6

Fig. 3

Fig. 7

Fig. 8

Fig. 9

Fig. 1

Fig. 2

76

Cross-halved joint

The third halved joint we deal with is the cross-halved joint (Fig. 2). It is used where two

members cross each other.

The sequence of operations to construct this joint is similar to the tee-halved joint, but instead

of a pin and a socket, two sockets have to be marked and cut.

Stopped Tee-halved joint

In this joint the socket is stopped away from the edge and the pin

is cut short, so that in the assembled joint the end grain of the

piece is not seen (Fig. 3.) Otherwise, the same sequence is

followed as for the tee-halved joint.

Common Mortice and Tenon joint

This is one of the most common and strongest forms of framing joint (Fig. 1). The sequence

of operations to construct a mortise and tenon joint for frame-like constructions is almost the

same as for box-like constructions. Of the four types of mortise and tenon joints mentioned in

this chapter, we will only go into detail about the construction of one of them, common

mortise and tenon.

Constructing the joint:

Step 1 - Preparation of timber

Prepare the timber using the FEWTEL (Face Side, Face Edge, Gauge for Width, Gauge for

Thickness, Shoot the End, Measure the required Length) method.

Step 2. Marking out

(a) Mark out the position of the mortise and square

the lines across the face side and edges, using a

try square and pencil (Fig. 2).

(b) Mark out the length of the tenon on the other

member. Allow 3 mm waste on the end. Square

lines all around (Fig. 3).

(c) Set a marking gauge to the size of the

tenon (one-third of the width of the

piece) and mark around the end of the

tenon (Fig. 5). Mark the waste.

(d) Use the same setting to mark both edges

of the mortise and mark the waste (Fig.

4). Do all marking from the face side.

(e) Check the marking, using the pieces as

a guide by placing them over the marks

(compare this sequence to the mortise

Fig

. 2

Fig

. 3

Fig. 4

Fig. 5

Fig. 1

Fig. 3

77

and tenon for box-like constructions).

Step 3 - Cutting the mortise

(a) Most of the waste may be bored out (Fig. 6).

Bore halfway through from both edges. Make

sure you keep the brace at a 900 angle to the

edge.

(b) Chop out the remaining waste, chiseling

halfway through from both edges. Leave

about 2 mm extra to prevent damage to the

sides of the mortise during chiseling (Fig. 7).

(c) When most of the waste is out, chisel out the

remainder to the line (Fig. 8).

Note:Keep the cutting edge of the chisel across the grain.

Step 4 - Cutting the tenon

(a) Rip the sides of the tenon, sawing on the waste side of the lines(Fig.9)

(b) Saw in steps (see tee-halved joint).

(c) Carefully saw the shoulders, keeping the saw vertical and on the waste side of the line

(Fig. 10 &11).

Step 5 - Assembling the joint

(a) Check whether the members fit together (see

Assembly section for the mortice and tenon

joint for box-like constructions).

(b) Clean up inside the joint where it cannot be

reached after assembly.

(c) Assemble the joint with glue.

(d) When it is dry, plane off the waste of the tenon.

(e) Clean up the edges and sides with a smoothing plane.

Note:The importance of marking the waste as you mark out the pieces. This cannot be over-

emphasized. Most construction mistakes are made by cutting on the wrong side of the line,

due to improper marking.

Haunched Mortise and Tenon joint

Another type of mortise and tenon for frame -like

constructions is the haunched mortise and tenon

joint (Fig. 1). This joint is used where one member

meets another at a corner.

The width of the tenon is reduced to 2/3rd of the

width of the board and the mortise size is reduced to

suit (Fig. 1).

Fig. 6

Fig. 7

Fig. 8

Fig.

11

Fig.

10

Fig. 9

Fig. 1

Fig. 2

78

A haunch is left on the tenon to prevent it from twisting in the mortise. The length of the

haunch is equal to the thickness of the tenon and it fits into a recess above the mortise, called

the haunching.

Otherwise, the sequence of operations for construction of this kind of joint is the same as for

the common mortise and tenon joint. When you make the cutting list for this type of joint, the

allowance in length for the member with the mortise should be 25 mm instead of 12 mm to

help prevent splitting of the haunching.

Stub Tenon Joint

Where the end grain of the tenon and the opening of the mortise must be hidden, the stub

tenon joint is chosen (Fig. 2). in this joint the tenon does not pass through the mortised

member, but is stopped inside. The sequence of operations for constructing this joint is the

same as for the common mortise and tenon joint. Stub tenons are also used for box-like

constructions.

At times a combination of the haunched and stub tenons is required. This is called a haunched

stub mortise and tenon joint.

Securing the joints:

(a) Instead of nails to secure mortise and tenon joints, either pegs or wedges can be used.

(b) One or two holes are drilled

through the assembled joint and

wooden dowels, or pegs, as they

are called in this case, are

inserted with glue to securely fix

the join (fig. 1).

(c) To make the dowels, plane off

the corners of a square piece of

hard wood, until the piece is

round. When the dowel is cut to

length, chamfer the ends and cut

a groove along the length to permit air and excess glue to escape (Fig. 1, a - e).

Follow the steps below to secure a joint by means of wedges.

(a) Cut the mortice with an allowance of 2 mm in width, tapering from the outside edge

to about 2/3rd of its depth (Fig. 2).

(b) Make cuts in the tenon to receive the wedges.

(c) To prevent splitting of the tenon, drill small holes at the end of each cut.

Fig. 1

79

(d) Cut the wedges from small pieces of waste wood; they should have the same length

as the tenon.

Haunched mortise and tenon joints in frame-like constructions should not be wedged,

because of the danger of breaking off the small haunch at the corner of the joint. Both wedges

and pegs can be used for securing mortise and tenon joints in boxlike constructions.

Bridle Joint

Bridle joints are similar to mortise and tenon joints. They consist of

a pin and a socket (Fig. 1). The thickness of the pin is 1/3rd of the

thickness of the member. The two types of bridle joint are the tee

bridle (Fig. 1) and the corner bridle. Here we will only go into detail

about the tee bridle, since the" construction of the corner bridle joint

follows much the same procedure.

Constructing the joint: HAUNCHED-CHECK

Step 1 - Preparation of the timber.

Prepare the timber using the FEWTEL (Face Side,

Face Edge, Gauge for Width, Gauge for Thickness,

Shoot the End, Measure the required Length) method.

Step 2 –

Marking out

(a) Mark the position of the pin on one

member, making the distance between the

shoulders equal to the width of the other

piece. Square the lines all around the piece

with a try square and pencil (Fig. 2).

(b) Mark the length of the socket (plus 2 mm

waste) on the end of the other member,

making the length equal to the width of the

pin. Square the lines across the face side and

on both edges (Fig. 3). Remember to smooth

the pieces before using them to mark.

SOCKE

T

PI

N Fig.

1

Fig. 2

Fig. 2

Fig. 3

Fig. 5

Fig. 4

80

(c) Set a marking gauge to l/3rd of the thickness of the member and gauge along both

edges of the pin. Use the gauge from the face side only. Mark the waste with small

crosses (Fig. 4).

(d) With the same setting on the gauge, mark around the end of the socket. Mark the

waste (Fig. 5).

(e) Mark the other side of the socket in the same manner, from the face side, with the

gauge set at 2/3rds of the thickness of the piece. If you have a gauge with 2 pins, mark

both lines at once.

(f) Check the fitting.

Step 3 - Cutting the pin

(a) Carefully saw the shoulders down to

the gauge line, sawing on the waste

side of the line (Fig. 6).

(b) Chisel away the waste, chiseling

halfway through from both edges

(Fig. 7).

Step 4 - Cutting the socket

(a) Rip the sides of the socket down to

the required depth, sawing on the waste

side of the lines (Fig. 9). Saw in steps (see

Tee-halved joint, cutting the pin.

(b) Chop out the waste with a mortise chisel,

chiseling halfway through from both

edges (Figs. 10 &11).

Step 5 - Assembling the joint

(a) Clean up the inside edges which cannot be

reached after the joint is assembled.

(b) Assemble the joint with glue and nails.

(c) When the glue is dry, plane off the waste

of the socket.

(d) Clean up the sides and edges with a smoothing plane.

Corner Bridle Joint

The corner bridle joint is used where members meet to form

the corner of a frame. Like the Tee-Bridle, it consists of a pin

and a socket (Fig. 12).

The pin is constructed like the tenon in the sequence of operations for the mortise and tenon

joint for frame-like constructions. The socket is constructed in the same way as the socket for

the tee bridle joint, above.

Fig. 6

Fig. 7

Fig. 8

Fig. 11

Fig. 10 Fig. 9

Tenon

Socket

Fig. 12

81

Widening Joints

Widening joints are joints used to make a single,

wide board by joining two or more narrow

boards along their length, edge to edge (Fig. 1).

The boards that will be joined must first be

marked. Lay the boards out in the desired

position and mark them with a triangular mark over all the boards (Fig. 1). The triangle

should point upwards. This mark will help us to keep in mind the position of each board

during the steps that follow.

Plain Glued Butt Joint

This is the simplest widening joint (Fig. 2). The edges of the boards are planed perfectly

straight and square, and then butted together. The joint is glued and clamped tightly to force

out the surplus glue. For narrow pieces this is done with G-clamps. For wider pieces, wooden

or metal sash clamps are used.

Dowelled Widening Joint

This joint is similar to the plain glued butt joint, but

strength is added by means of cylindrical wooden pins,

called dowels. Dowels are made as explained in the

section on securing joints. The dowels are then glued

into holes in the edge of each board (Fig. 3). The

diameter of the dowels should be about one-third of the

thickness of the pieces that are being joined.

The holes should be about as deep as the boards are

thick, and they should be slightly countersunk.

Mark out the position of the dowels by putting the boards on top of each other, sides together

and marking both edges at the same time. The centre can be marked with a marking gauge,

marking from the face side.

Metal or wooden sash clamps are used to press the boards together during gluing.

Rebated Joint

In this widening joint, the edges of the boards are rebated to match

each other (Fig. 1). The rebating is done with either an ordinary

rebate plane or an adjustable one. This joint is stronger than the

plain glued butt joint,

How to plane a rebate with an ordinary rebate plane:

Fig. 1

Fig. 2 Fig. 3

82

Step 1

Mark the depth and width of the rebate with a marking

gauge (Fig. 2).

Step 2

Fix a wooden guide strip along the line that marks the

width of the rebate (Fig. 2). The guide strip must be

perfectly square and it should be flat.

Step 3

Plane until you reach the line marking the depth

of the rebate. Take care that the side of the plane

is always against the guide strip, so that the width

of the rebate is the same along the whole length.

If you notice that you are planing against the

grain, stop just before you reach the required

depth and plane from the other direction. This

will ensure that the surface of the rebate is smooth.

An important point in planning rebates is setting the plane correctly. The side of the cutting

iron that faces the rebate must be set so it is exactly flush with or only slightly coming out at

the side of the plane.

METALWORK JOINTS

Sheet metal is simply metal formed into thin and flat pieces. It is one of the basic forms used in

metalworking, and can be cut and bent into a

variety of different shapes. Sheet metal is

available in flat pieces or as a coiled strip. Sheet

metal has uses in car bodies, airplane wings,

medical tables, roofs for buildings and many

other things.

Types of joints in metalwork:

Sheet metal is frequently used in all levels of

construction, be it home, public or commercial.

The most useful way to permanently join two

pieces of metal together is to weld them. However, the use of fasteners, rivets, screws and solders are

also very widely used in the sheet metal industry.

Fasteners

A fastener is a device that mechanically joins two or more metals together. Nuts and bolts, washers,

screws and rivets provide a convenient method of securing parts.

Fig. 1

Guide Strip

Depth

Width Fig. 2 Fig. 3

83

Riveting

Riveting is a simple way to join metal parts together. Rivets are made of

soft iron for general engineering: aluminum alloy for aircraft work and soft

aluminum of copper for non-metallic substance. A wide range of special

rivets are available.

Rivets are fasteners, like nails and screws. Rivets themselves are smooth,

metal cylindrical shafts with a head on one end and a buck-tail on the other.

Rivets are described according to:

Shank - solid, tubular, or special type such as Riv-Nut

Metals - copper, aluminum alloy and soft steel,

Shape of head

Diameter of shank

Length of shank.

Solid shank rivets are the type commonly used for most purposes in

sheet metal work.

Countersunk rivets are useful where streamlining is needed, as in air-

planes. The countersinking is done as for bolts and screws. It permits

the head of the rivet to be placed flush with the surf ace of the metal.

Roundhead rivets are used where a strong union is required but

where the projection of the head causes no concern.

Flathead rivets are used in such constructions as fuel tanks.

Rivets Bolts Nuts

Source: Basic Engineering – R. L.

Timings

Source: Photographed

pictures

Dyna Bolts Spring Washer Screws

84

Mushroom head rivets are used where it is necessary to shorten the height of the rivet head above

the metal surface, as for example in aircrafts.

Pan head rivets are very strong, and are, therefore, widely used for girders and heavy constructional

engineering.

To use a rivet, it is placed through a hole (same size as rivet) drilled through two flat objects (usually

metal). A ball pein hammer is used to smash one end of the rivet, which expands to about one and a

half times the width of the rivet in order to hold the rivet in place and objects together.

Pop Rivet

There are many different types, sizes and composition of rivets which

are used for various needs, from plastic to wood, as well as metal.

The pop or blind rivet is used in these types of application. Pop or blind

rivets have a tubular shape with a mandrel through the center. One end

looks like a long nail. A special tool or gun is used to smash the rivet

and cut off the long end.

Using a rivet gun can be a highly effective method of attaching various materials, especially metal

together in a permanent way. Though the materials can be separated by simply drilling out the rivets,

this is not a difficult process, however you should take care when riveting and do not rush, as this

could be a hazard, especially to people who do not know what they are doing.

Pop rivet guns can be very inexpensive to use as are the rivets. You can buy with the tool or

separately. It may be beneficial to get a good quality rivet tool from the start, however a cheaper one

will be sufficient depending on the work at hand.

Screws

There are two types of screws, machine and wood screws. Both

are made of metal; however the machine screw has a constant

diameter and joins with nuts while the wood screw is tapered

A pop-rivet gun

Drilling for rivet Inserting rivet to

pop rivet gun

Riveting

85

and grips to the actual wood surface. Screws are generally made from low to medium carbon steel

wire, but other tough and inexpensive metals may be substituted, such as stainless steel, brass, nickel

alloys, or aluminum alloy. Screws come with many different styles of heads, the three most

common are flat, round and pan.

Types of Screws:

(i) The countersunk head are probably the most common. They do not

protrude above the surface so can be filled and painted over and become

invisible. This type of head is used in butt hinges and in metal where the

head is to be flat with the surface. The heads have an included angle of

82°.

(ii) These are used when a countersunk head is not required.

(iii) These are similar to round head except the top of the head is flat, self-threading

metal screws are a good example.

Screws sizes are listed with the shank size first then the length. Shank sizes are denoted by numbers,

the larger the number the larger the shank, the most common sizes are #6, #8 and #10 so a medium

size screw 1½" long would be listed as: #8 x 1½".

Screwdrivers

The screwdriver is used to drive screws and to remove

them. These are made in a variety of styles, such as the

plain, ratchet, offset, and spiral. The screwdriver consists

of a blade, the tip of which is shaped to fit the slot in the

head of a screw, and a handle, which may be part of the blade. The sizes of screwdrivers are

determined by the length of the blade, which is

measured from the tip to the beginning of the ferrule, as

well as by the width of the tip.

These are a basic item to have in assorted sizes, not as

popular as they once were but still necessary. It is very

important that the bit be the right size for the slot in the

screw otherwise it will probably slip and strip the edges

of the slot making the screw nearly impossible to work with. The bit

must be kept in good condition by grinding or filling it square as they

tend to wear at the outside corners. When purchasing screws for

projects, be advised to use Phillips or Robertson style screws.

At least the three sizes, #1, #2, and #3 should be in your tool box. This

type of screwdriver will sit on the end of the screw as it is started and is

Flat

Round

Pan

Sides

parallel

Width of

tip

Thickness

of tip

End

of tip

straig

ht

Phillips

head

screwdri

ver tip

Phillip

s head

screw

Flu

te

Phillips Head Screwdriver

86

less likely to slip as it is being driven.

In order to allow for the screw to be driven easily through the metal, a pilot hole is drilled.There are

two basic reasons for drilling pilot holes:

(i) for tight fitting, and (ii) prevent the material from splitting

The pilot hole in the top piece should allow for easy fit of the screw shank, and allow the threads on

the screw to get a good grip without stripping in the bottom piece. Pilot holes can be drilled with

special bits that are made for different size diameter and length of screws and will also countersink the

head of the screw.

Soldering

Soldering is a method of joining

metal by using an alloy having a

lower melting point than the metal

being joined. Good for joining

dissimilar materials. Most

common solders are lead-tin

alloys. The solder is an alloy of

lead and tin that melts at a

relatively low temperature, from

350 to 450 degrees, and the source

of heat may be an electric

soldering gun, an electric

soldering iron or a portable propane torch.

Soldering irons have copper bits because copper has an attraction for solder, has a high thermal capacity,

it is malleable, soft metal and is a good conductor of heat. It is a tool used to transfer heat and melted

solder into suitably designed metallic connections and sheet metal joints.

The process of soldering involves:

(i) Tinning the metal surface.

(ii) Filling the space between the

tinned surfaces with solder.

Source: Metalcraft Theory and Practice –

John R Bedford

87

A fluxing agent is used to assist the flow of solder and increase bonding strength. Fluxes are of two

general types, zinc chloride and resin. The functions of a flux are:

(i) They keep the metal clean during heating.

(ii) They break down the surface tension of the solder enabling it to flow.

Activity

1. Sketch the following joints used in woodworking

a. Brittle joint

b. Stub mortise and tenon joint

c. Hauched mortise and tenon

d. Rebate joint.

2. Sketch the following screws and write down its uses

a. Countersunk

b. Round head

c. Flat head

d. Pan head

3. The process of soldering involves two processes. Name the two processes.

4. Sketch a soldering iron and name its parts and write down the uses.

Source: Metalcraft Theory and Practice – John R Bedford

Tinning the metal

surface

Adding solder to fill the joint

88