MISS. HANNA’S CLASSROOM RULES 1. “My students never fail. I believe in you and so shall you!” – Miss.
Hanna’s Quote!
2. Come to class on time.
3. Bring a positive attitude.
4. Come prepared and bring your books and notes.
5. Stay on task.
6. Complete work on time.
7. Pay attention and don’t talk while the teacher is talking.
8. Listen carefully.
9. Raise your hand to ask a question.
10.Work quietly.
11.No personal grooming, electronics which will disturb the class and other students who are working.
12.Respect personal space.
13.Ensure chairs and tables are in order before leaving class.
14.Be kind with your words and actions.
15.Respect, obey and follow all school rules and personal property.
16.Work in a safe manner.
I appreciate and thank all my students for their effort in
respecting and keeping up with our classroom rules!
A video or 2 for you
Basic Engineering Drawing http://www.youtube.com/watch?v=FFDH
ScQFscw
Orthographic: http://www.youtube.com/watch?v=vsnvo
5rl66w
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Introduction to Drawing Tools
Module Objectives
Identify and describe the use of engineering drawing
equipment.
Recognize different methods of laying out engineering
drawing papers.
Demonstrate the use of scales.
Produce a simple drawing paper layout including border
and title block.
Introduction to Drawing Tools
1.0 Introduction
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Technical drawing is the study of the procedures,
tools, supplies, skills and techniques used to record
and communicate the shape and size of a product.
Every product we have today (e.g. cars, houses,
machines, etc…), began as an "idea" in some person's
head.
Before these "ideas" became products, they
had to be drawn on paper so as to show
what the idea looks like from different
directions, Fig.1.1.
Fig 1.1.
2.0 Drawing instruments
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To prepare a drawing, one can use manual drafting
instruments as shown in Fig.1.2, or computer-aided
drafting (CAD).
If the drawing is made without either manual
instruments or CAD, it is called a freehand sketch.
The following instruments are essential and should be
available to produce a good quality
technical drawing.
Fig. 1.2: Manual
Instruments
2.1 Drawing Boards
Drawing Boards can range from simple boards,
like the one shown in Fig.1.3, to complicated
drawing machines that would be used in
engineering drawing office.
The surface of the board should
be dusted and smooth.
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Fig. 1.3: Drawing Board
2.2 T-Square
T- Square is composed of a long strip, called the blade;
it is placed on the drawing board and provides a
constant horizontal edge.
The T-square is shown in Fig.1.4 below.
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45/45 triangle 30/60 triangle
2.3 Set Square
Set Squares are best made from transparent
plastic.
The two standard set squares that are commonly
used are 30/60 and 45/45 degrees triangles as
shown in Fig 1.5.
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2.4 Pairs of Compasses
There are basically two types of compasses
1. Pencil compasses which are used to draw circles.
Circles up to 300 mm diameter are drawn using a
large radius compass.
2. Spring bow compass which is
used to draw circles of 50 mm
diameter or less. (Fig.1.6) to the
right.
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2.5 Protractor
Protractors measure angles other than those
obtained by the set squares and found in half circle or
full circle types, Fig. 1.7 shown below.
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2.6 Ruler
A 300 mm ruler with one edge marked in
centimeters and millimeters is necessary, Fig.1.8
below.
In a fully equipped drawing machine, horizontal and
vertical rulers with graduations in mm or inches
are attached to the drafting head.
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2.7 Drawing pencils
Pencils have nine grads of hardness from H to 9H and
seven grades of softness from B to 7B as shown in
Fig. 1.9.
Fig.1.9: Pencil lead grades.
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2.6 Eraser
Erasers are available in different hardness and
are used to erase pencil work.
The common eraser used is a block-shaped
vinyl eraser (Fig.1.10).
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2.8 Circle template
Circle templates are useful for drawing small
circles quickly and to join lines with a radius, A
circle template is shown in Fig.1.11.
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3.1 Sizes of the drawing paper
Drawing paper is available in ‘A’ series, ‘B’
series, and rolls of the International
Organization for standardization (ISO), but
series ‘A’ is preferred.
Paper sizes for series ‘A’ are based on the
A0 size, which has an area of 1 square
meter.
An A0 size sheet can be divided up evenly
into the various other sizes (A1, A2, A3,
A4…) simply by halving the sheet on the
long side in each case as shown in Fig. 1.12
on page 6 in Module 1.
3.0 Drawing Paper
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3.2 Scales
In order to produce drawing showing
components in detail or as plans it is often
necessary to use a scale.
This can increase the size of the drawing in
comparison to the real size of the component.
Some of the recommended scales are listed
below:
Enlargements scales: 2:1 20:1 50:1 10:1
Full (same) size: 1:1
Reduction scales: 1:2 1:10 1:20 1:100
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3.3 Layout of the drawing paper
Drawing sheets of all sizes have standard layout.
It is usual for each sheet to be provided with a drawing
frame a short distance from the edge of the paper as
shown in Fig.1.13 shown on page 6 Module 1.
Each drawing sheet has to be provided with a title block
which represents the general information source for a
drawing.
It is normally placed in the bottom and at least contains
the title of the drawing, the name of the draftsman, the
scale, and the date.
Fig 1.13 a: Layout of the A3 drawing paper.
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Fig 1.13 b: Layout of the A4 drawing paper.
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3.4 Line type
Fig. 1.14 (on page 7 in Module 1) shows the
types of line which are commonly used in
engineering drawings such as visible lines,
hidden lines, center lines, dimension lines,
extension lines, and leader lines.
Fig. 1.15 (on page 7 in Module 1) shows an
application for the use of different types of
Line.
4 Main Line Types
INSTITUTE OF APPLIED TECHNOLOGY 21
Technique of Lettering
Printing increase the information that is provided on a drawing.
Printing must be clear and neat so that it is easy to read.
Use guide lines 5 mm apart as illustrated in Fig. 1.16.
These guide lines can be used to make sure that all letters and
numbers have the same size.
Always print using capital letters.
All letters and numbers should touch the top and bottom guide lines.
Guide lines should be 5 mm apart as explained earlier.
INSTITUTE OF APPLIED TECHNOLOGY 24
5.1 In class activities
Draw the objects shown below in full size using different
drawing tools such as compasses, set squares and tee
square. Use an A3 sheet to create the drawing with the
same layout shown below.
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5.2 Home work
Draw all 4 drawings shown on
page 9 & 10 in Module 1
Submission date – Due next class
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Technical Drawing Instruments
Students must bring all their
drawing instruments next class
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