MODULE 1: WEEK 1-2
Engineering Drawing 1
Prepared by:
ENGR. MERIAM P. LEOPOLDO
ENGR. ALFONSE IRENEO T. ESTIBAL
Lesson 1: Introduction to
the design process
LESSON 1 OBJECTIVES
1. BE ABLE TO KNOW THE DIFFERENT DRAWING INSTRUMENTS
AND THEIR USES.
2. UNDERSTAND THE IMPORTANCE OF GRAPHICAL & WORD
LANGUAGE IN TECHNICAL DRAWING.
3. APPLY THE KNOWLEDGE IN WRITING LINES AND LETTERS
FOR EFFICIENT DRAWING.
History of Drawing
• Pictures as forms of communication /
conveying ideas
• Orthographic Projection
Gaspard Monge – French mathematician
and father of descriptive geometry
Source: http://tolerancing.net/engineering-drawing/engineering-drawing-history.html
History of Drawing
➢ Perspective drawing technique was invented during
the Renaissance period (1300-1500)
➢ Descriptive geometry was invented by Gaspard Monge
in 1765
➢ Orthographic projection technique was invented during
the Industrial Revolution period (1770-1850)
➢ 2-D CAD systems were developed in the 1980s
➢ 3-D CAD systems were developed in the 1990s
Source: http://tolerancing.net/engineering-drawing/engineering-drawing-history.html
DRAWING INSTRUMENTS
& THEIR USE
1. Drawing/Drafting Table
It is a stable platform for
drawing and reading
blueprints. Most tables are
height adjustable so you can
stand or sit while working.
2. Triangular/Architect’s Scale
A triangular scale is a ruler that has a 3-
lobed cross-section with 6 different types
of scales on the edges (2 on each face)
used for measuring and preparing scale
drawings such as blueprints and maps.
Using this, most blueprints are drawn
scaled down rather than in their actual
size.
How to use the triangular scale:
https://www.youtube.com/watch?v=K7-f-
c-ue1A
3. 45, 30 & 60 degree Drawing Triangles
A triangle is a drafting tool used to
draw accurate parallel lines,
vertical lines, and other angled
lines. Generally, two right-angled
triangular pieces of differing
angles form one set.
How to use triangles:
https://www.youtube.com/watch
?v=jHB5kbQQ-kk
4. T-Square
A T-square is a technical drawing
instrument used by draftsmen
primarily as a guide for drawing
horizontal lines on a drafting table.
How to use the T-Square:
https://youtu.be/8XdUIvro4v4
4. T-Square
A T-square is a technical drawing
instrument used by draftsmen
primarily as a guide for drawing
horizontal lines on a drafting table.
How to use the T-Square:
https://youtu.be/8XdUIvro4v4
5. Drawing Compass
It is used to draw circles or arcs.
This tool is also known as a pair of
compasses, or simply as a
compass. It can also be used for
measuring distances or more
precisely distances on the maps.
How to use a compass:
https://www.youtube.com/watch
?v=02XRad7s1Io
6. Technical Pen
Technical drawing pens, or drafting pens,
are the artistic tool preferred by
architects, engineers, illustrators, and
anyone else who depends on precise
and consistent lines. They typically feature
needle-point tips in assorted widths, such
as 0.5 mm and 1.0 mm—making them
ideal for any detailed linework.
How to properly use the tech-pen to
avoid blotting (Tagalog):
https://www.youtube.com/watch?v=-
uH7DJQctvs
TYPES OF LINES & LETTERS
Elements of Engineering Drawing
Graphics Language
Describe a shape (graphical presentation)
Word Language
Describe an exact size, location and specification of
the object
Elements of Engineering Drawing
Elements of Engineering Drawing
Engineering Drawing
Graphics Language Word Language
Geometric
Projection Lettering
Construction
Lines
LETTERING
TYPES OF LETTERING TECHNIQUES
VERTICAL
TYPES OF LETTERING TECHNIQUES
INCLINED
Inclined (italic)
capital letters and
numerals are similar
to vertical
characters, except
that their slope is
about 68 degrees
from the horizontal
PROPER SPACING
1. The background area between letters, not the distance
between them should, be approximately equal.
2. Words are spaced well apart, but letters within words
should be spaced closely.
PROPER SPACING
3. For either uppercase or lowercase lettering, make the
spaces between words approximately equal to a capital
“O”.
4. Avoid spacing letters too far apart and words too close
together.
SPACING BETWEEN LETTERS
STRAIGHT-STRAIGHT STRAIGHT-SLANT
STRAIGHT-CURVE CURVE-CURVE
SPACING BETWEEN LETTERS
CURVE-SLANT SLANT-SLANT
L &T
TIPS & TRICKS FOR EFFICIENT LETTERING
1. All figures and letters on a drawing should be UNIFORM,
NEAT & CAREFULLY made.
2. SPELL words correctly.
3. Make letters and figures proper SIZE. Don’t make letters
too prominent, yet make them readable.
4. Keep your forearm on the table when lettering.
5. Make the letters clean-cut and dark.
6. Shift, or roll, the pencil frequently to prevent wearing
down in one place of the pencil.
7. Draw parallel light “GUIDELINES” to help with lettering.
COMMON MISTAKES IN LETTERING
A FRIENDLY REMINDER:
ALWAYS BE PATIENT AND CAREFUL!
TYPES OF LINES
TYPES OF LINES
1. OBJECT LINES
A visible line, or object line is
a thick continuous line, used
to outline the visible edges
or contours of an object.
HEAVY = 0.5MM TECHPEN
TYPES OF LINES
2. HIDDEN LINE
is a medium weight line, made of
short dashes about 1/8” long
with 1/16”gaps, to show edges,
surfaces and corners which
cannot be seen. Sometimes they
are used to make a drawing
easier to understand. Often they
are omitted in an isometric view.
MEDIUM = 0.3MM TECHPEN
TYPES OF LINES
3. SECTION LINES
are used to show the cut
surfaces of an object in section
views. They are fine, dark lines.
Various types of section lines
may indicate the type of
material cut by the cutting plane
line.
LIGHT = 0.1MM TECHPEN
TYPES OF LINES
4. CENTER LINES
are used to indicate the centers
of holes, arcs, and symmetrical
objects. They are very thin (size),
long-short-long kinds of lines.
LIGHT = 0.1MM TECHPEN
TYPES OF LINES
5. DIMENSION LINE
Dimension lines are thin and are
used to show the actual size of
an object. There are arrowheads
at both end that terminate at
the extension lines.
ARROWHEADS
LIGHT = 0.1MM TECHPEN
TYPES OF LINES
6. EXTENSION LINES
Extension lines are also thin lines,
showing the limits of dimensions.
Dimension line arrowheads touch
extension lines.
LIGHT = 0.1MM TECHPEN
TYPES OF LINES
7. LEADER LINE
Leaders are more thin lines used
to point to an area of a drawing
requiring a note for explanation.
They are preferably drawn at a
45° angles.
LIGHT = 0.1MM TECHPEN
TYPES OF LINES
8. CUTTING PLANE LINE
A cutting plane line (very heavy)
helps to show the internal shape at
a part or assembly by slicing
through the object.
HEAVY = 0.5MM OR GREATER TECHPEN
TYPES OF LINES
9. BREAK LINE
Used to remove, or ‘break out”
part of a drawing for clarity, and
also to shorten objects which have
the same shape throughout their
length and may be too long to
place on the drawing.
Short and long break lines are used for flat surfaces.
Cylindrical are used on rods, dowels, etc.
TYPES OF LINES
10. PHANTOM LINE
Are long-short-short-long lines most
often used to show the travel or
movement of an object or a part in
alternate positions. It can also be
used to show adjacent objects or
features.
LIGHT = 0.1MM TECHPEN
TYPES OF LINES
11. BORDER LINES
Continuous lines used to show the
boundary of the drawing or to
separate different objects drawn
on one sheet. They are also used to
separate the title block form the
rest of the drawing.
HEAVY = 0.5MM OR GREATER TECHPEN
Source:
https://openoregon.pressbooks.pub/blueprint/chapter/unit-
1-the-language-of-lines/
END OF LESSON 1
