Republic of the Philippines

DEPARTMENT OF EDUCATION
Region I
Pangasinan Division II

Luciano Millan National High School

Asingan,Pangasinan

MODULE 2
IN

SMAW NC II-GRADE 12

Interpret Drawing and Sketches

Common Competencies
OBJECTIVES:

1. Identify Standard Alphabet of Lines;

2. Identify Orthographic/Isometric Views; and
3. Interpret Standard Drawing Symbols, Dimensional Tolerances and Notations

Prepared By: Checked /Validated By:

Wpilmer J. Directo Evangeline A. Mariano

SHS- Teacher II Asst. Principal II

Approved By:

Jose S. Venenciano
Principal IV
How to use this module
Before starting the module, I want you to set aside other task that will disturb you while enjoying the lessons. Read the
simple instructions below to successfully enjoy the objectives if this kit.

1. Follow carefully all the contents and instruction indicated in every page of this module.

2. Write on your notebook the concepts about the lessons. Writing enhances learning, that is important to
develop and keep in mind.

3. Platform all the provided activities in the module.

4. Let your facilitator/guardian assess your answer.

5. Analyze conceptually the posttest and apply what you have learned.

6. Enjoy studying.

Parts of the module

 Rationale/Introduction - these are what you will able to know after completing the lessons in the module.

 Objectives- these are the expected competency you are expected to be learned and performed.

 Pre-test - this will measure your prior knowledge and the concepts to be mastered throughout the lessons.

 Discussion - this section is the discussion of the topics.

 Activities - this is a set of activities you will perform.

 Post-test - this will measure how much you have learned from the entire module.

 Reflection- these are your thoughts about the lesson you learned.

Unit of Competency Interpret Drawing and Symbols

Module Title: Interpreting Drawing and Symbols

I. INTRODUCTION

This module contains information and suggested learning activities on Interpreting drawings and
Symbols. It includes instruction and procedure on how to Interpret Drawings and Symbols.

Completion of this module will help you better understand the succeeding module on Contributing to
Quality System.

This module consists of three (3) learning outcomes. Each learning outcome contains learning
activities supported by instruction sheets. Before you perform the instruction, read the information sheets and
answer the self-check and activities provided. To ascertain your competence, your teacher will assess what you
have acquired when the knowledge necessary to perform the skill portion of the what particular learning
outcome.

Upon completing this module, report to your competence teacher for assessment to check your
achievement of knowledge and skills requirements of this module. If you pass the assessment, you will go to
the next competencies.

II. EXPECTED OUTCOMES:

Upon completion of the module the students should be able to:

LO1 Identify Standard Alphabet of Lines;

LO2 Identify Orthographic/Isometric Views; and
LO3 Interpret Standard Drawing Symbols, Dimensional Tolerances and Notations
III. PRE-TEST

Multiple Choice
Directions: Read and analyze the statement carefully. Choose the best answer and write the letter only in
your answer sheet.

1. Which is a thick solid line used to show the visible shape of the object.
a. Hidden line b. Center line c. Extension line
d. Object line e. Short break line
2. Which is a heavy irregular line drawn
a. Hidden line b. Center line c. Extension line
d. Object line e. Short break line
3. Which broken line is made up of a series of short and long clashes or alternately spaced, to show the
center of circles, arcs, and symmetrical objects?
a. Hidden line b. Center line c. Extension line
d. Object line e. Short break line
4. Which broken line of medium thickness is used to show the edges and outline not visible to the eye.
a. Hidden line b. Center line c. Extension line
d. Object line e. Short break line
5. Which fine lines extend from the
a. Hidden line b. Center line c. Extension line
d. Object line e. Short break line
6.This is information used as a guide by the welder in constructing or assembling metal products.
a. Drawings c. Weld Symbols b. Sketches d. Welding Symbols
7.Parts of the welding symbol used to indicate position of the weld.
a. Reference Line c. Arrow b. Weld Symbol d. Tail
8.The symbol triangle attached to the reference line indicates the type of weld.
a. Bead c. Square Butt Weld B. Fillet d. Single V Butt Weld
9.When special notes are required for the welder to be informed, part of the welding symbol is indicated.
a. Reference Line c. Arrow b. Weld Symbol d. Tail
10. This symbol is a miniature drawing of the metal’s edge preparation prior to welding.
a. Reference Line c. Arrow b. Weld Symbol d. T

Program/Course: Shielded Metal Arc Welding (SMAW) NC1

Unit of Competency: Interpret Drawing and Symbols
Module Title: Interpreting Drawing and Symbols

Learning Outcome 1: Identify Standard Alphabet of Lines

INTRODUCTION

This lesson covers the knowledge skills and attitude required for identifying standard alphabet of
lines in accordance to International Standard Organization.

Assessment Criteria:

1. Alphabet of lines are identified according to International Standard Organization (ISO)

2. Alphabet of lines are clearly explained according to their uses.

Definition of Terms

Weld Symbol- it indicates the require type of weld and

supplemental implementation.

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 Tolerance- is the total amount of variation permitted for the
design size of a part.

Symbol -is a figure or character used in place of a word

or group of words.

Arrow Side- is a weld symbol that is written above the

reference line.

Other Side- is a weld symbol that is written above the

reference line.

Both Side- is a weld symbol that is written above and

below the reference line.

Reference Line- is written horizontally forming an obtuse

angle.

Concave- is a curve inward (see contour symbol).

Convex- is a curve outward (see contour symbol).

Tail- is a part of an arrow symbol on a welding blue

print where specifications are placed

INFORMATION SHEET #1.1

Identify Standard Alphabet of Lines

Alphabet of Lines

Lines are the bases of all drawing. They are used even from simple drawing to the difficult ones.
Practice, exercise and correct use of techniques in the making of lines will give student experience in
technical sketching. Moreover, constant practice will help students develop skill in making lines and
use of pencils. It should be remembered that the basic requirement for line construction is clarify of
line produced.
In practice, the kind of line produced, depends on the hardness of the pencil. For drawing using
pencil, the medium and light lines are more prepared.
There are conventional lines used in drawing. These lines are called alphabet of line and each line
serves a particular purpose. These lines may either be drawn freehand or they may be drawn
mechanically.

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 There are several different types of lines used on a print and each has different meaning. To be
able to interpret a print, the reader should have knowledge of these lines. These lines are called alphabet
of lines.

1. Object Line. Thick solid line used to show the visible shape of the object.

___________________________

2. Hidden Line. Broken line of medium thickness and used to show the edges and outlines not
visible to the eye.

- - - - - - - - - - - - - - - - - - - - - ----

3. Center Line. Fine, broken line made up of a series of short and long dashes alternately
spaced. To show the center of circles, arcs, and symmetrical objects and to aid in
dimensioning the parts of the object.

__ _____ __ _____ __ ______ __

4. Extension Line. Fine lines that extend from the object with a slight break between and it is
used to show dimensioning points.

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5. Dimension Line. Lines used to indicate the measurement of objects. It consists of three
parts: arrowheads, fine line, and number or measurement. The fine lines have the same
thickness or weight as the projection line. The arrowheads are short heavy strokes (called
flares) placed at the extremities of this fine line. The shape of an arrowhead is like the point
of an ordinary pen. The number or figure is usually positioned at the middle of the fine line
and its axis is perpendicular to it.

6. Leader Line. Fine, straight line with an arrowhead or round solid dot at one end and usually
drawn at angle. Points directly to a surface for the purpose of dimensioning or adding a note.
A dot may be used at the end of the straight line where reference is made to a surface area.

7. Cutting Plane Line. A thick broken line made up of a series of one long and two short
dashes alternately spaced. The arrowheads are placed at right angles to the cutting plane line.
The purpose of this line is to indicate where an imaginary cut is made through the object.
The arrow points in the direction in which the section should be viewed. Letters next to the
arrowheads identify the section in cases where more than one section is shown on the
drawing. These lines are oriented vertically, horizontally, or at the actual angle at which the
part is drawn.

8. Section Lines. Series of fine lines-solid or solid and broken-arranged in specific patterns.
They may be shown either straight or curved. When shown straight, they are usually drawn
at a 450 angle. It is used to indicate the imaginary cut surface referred to by the cutting plane
line. To represent various kinds of materials.

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 9. Chain Line. Heavy, broken line made up of a series of long and short dashes alternately
spaced. It is used to indicate the location and extent of a surface.

__________ ____ __________

10. Short Break Line. Heavy, irregular line drawn freehand used to show a short break to
conserve space on a drawing.

11. Long Break Line. Ruled, light line with freehand zigzags used to show a long break to
conserve spaced on a drawing.

12. Phantom Line. Light, broken line made up of a series of long and two short dashes used to
show alternate positions of a part; to show relationship of existing part to new part; and to
show machined surfaces.

__________ __ __ ________ __ __ __________

Self – Check 1.1

Alphabet of Lines

Multiple Choice:

Directions: Read and analyze the statement carefully. Choose the best answer and write the letter
only in your answer sheet.

1. Fine lines with arrowheads usually touch the extension lines and show distance given by the dimensions.
a. Hidden Lines c. Extension Lines
b. Dimension Lines d. Cutting Plane Lines
2. The purpose of this line is to indicate where an imaginary cut is made through the object.
a. Hidden Lines c. Extension Lines
b. Dimension Lines d. Cutting Plane Lines
3. Series of fine lines-solid or solid and broken arranged in specific patterns used to represent various kinds of
materials.
a. Chain Line c. Section Line
b. Break Line d. Phantom line

4. Fine lines that extend from the object with a slight break between and it is used to show dimensioning points.
a. Chain Line c. Section Line
b. Object Line d. Extension Line

5. Used to show the visible shape of the object.

a. Chain Line c. Section Line
b. Object Line d. Extension Line

6. Ruled, light line with freehand zigzags used to show a long break to conserve
spaced on a drawing.

a. Chain Line c. Section Line

b. Long Break Line d. Phantom line

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 7 Heavy, irregular line drawn freehand used to show a short break to conserve
space on a drawing.

a. Short Break Line c. Section Line

b. Long Break Line d. Phantom line

8 Fine, broken line made up of a series of short and long dashes alternately
spaced.
a. Center line c. Extension Lines
b. Dimension Lines d. Cutting Plane Lines
9. Broken line of medium thickness and used to show the edges and outlines not
visible to the eye.
a. Hidden lines c. Extension Lines
b. Dimension Lines d. Cutting Plane Lines

10 Light, broken line made up of a series of long and two short dashes used to show alternate
positions of a part
a. Phantom line c. Section Line
b. Long Break Line d. Short Break Line

Program/Course: Shielded Metal Arc Welding (SMAW) NC1

Unit of Competency: Interpret Drawing and Symbols
Module Title: Interpreting Drawing and Symbols

Learning Outcome 2: Identify Orthographic and Isometric Views

INTRODUCTION

This lesson covers the knowledge skills and attitude required for identifying orthographic and
Isometric Views in accordance with the working plan.

Assessment Criteria:

1. Orthographic and isometric are clearly explained.

2. Orthographic and isometric drawings are identified based on plan.

Definition of Terms

Drawing - illustrating objects using drawing instruments

Sketching- freehand drawing

Orthographic View -refers to the different position of the object used in orthographic projection
Orthographic Projection - refers to the representation of the exact shape of
an object in two or more views

Isometric Drawing Pictorial drawing in which the horizontal lines are represented at angle of 300
with the horizontal axis.

Dimension lines -is used to indicate the measurements of objects.

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 INFORMATION SHEET # 2.1

Identify Orthographic and Isometric Views

Orthographic View Sketching

The term orthographic comes from the Greek words orthos and graphos
which mean to write and to draw. Orthographic sketching therefore is drawing using lines only.
This kind of drawing is simple. Its purpose is to represent a shape using two or more views.

 Orthographic Drawing
Figure can be viewed in three ways:
a. Frontal plane
b. Horizontal plane
c. Profile plane
 The frontal plane shows the shape of an object as seen from the front. This is
called FV.

 The horizontal plane shows the object as viewed from the top. This is called the
TV of an object.
 The profile plane shows the shape of the object as seen from the side, the
distance from bottom to top and front to back. This is called the SV of an object.

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 View is the different position used in orthographic projection that an object may be
projected and this is done by extending perpendicular lines to the plane from all parts of the object.

The Six Orthographic Views

A. Front View. Front view is observed directly behind the rear view.

B. Right Side View. View directly observed at the right of the front view and it is the
opposite of the Left Side View.

C. Top View. Top view is directly above the front view.

D. Bottom View. View directly observed beneath the front view. It is the opposite of the
Top View.

E. Rear View or Back View. View that is the opposite of the front view.

F. Left Side View. View directly observed at the left of the front view and it is the
opposite of the Right Side View.

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 ACTIVITY SHEET 2.1

Identify Orthographic and Isometric View

Orthographic Sketching

Sketching Orthographic Views

Procedure:
a. Know the dimensions of the object: the length, width and thickness.
Study the proportions of the parts and that of the whole object.
b. Check on the kind of view you wish to use in the object. Be sure
that the main surfaces are represented. More importantly check on
the size of the views taking care that they are proportioned
properly.
c. Draw the object using light lines first to give easier time for
erasures. Later when the view drawn is acceptable, the lines will be
made darker.
Sample orthographic views:

INFORMATION SHEET # 2.2

Identify Orthographic and Isometric Views

Isometric Drawing
Isometric drawing is a drawing wherein objects is represented by three skills and are seen at one
time. The term isometric comes from ISO which means equal and metric means measure. This means
therefore that the isometric view is in equal measure to its orthographic views. Isometric also means that
the measurements of the angles are equal as formed by their three axes.
There are three axes of an isometric drawing: the vertical, the left 20 degrees cross axis and the
right 30 degrees cross axes.

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 Operation Sheet 2.2

Identify Orthographic and Isometric Views

Isometric Drawing

Procedure:

1. Draw the vertical axis and then

lay the height.

2. Draw the left and right

degrees cross axis.

3. Measure the width and

depth of the object.
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 4. Draw parallel lines to the width
and depth to complete the three
faces of the object.

Self-Check 2.2

LO 2. Identify Orthographic/Isometric Views

TEST I
Multiple Choice:
Direction: Read and analyze the statement carefully. Choose the best answer and write the letter
only in your answer sheet.
1. This refers to the representation of the exact shape of an object in two or more views as they
seen perpendicularly from its surfaces.
a. Alphabet of lines
b. Isometric Drawing
c. Orthographic Drawing
d. Orthographic Projection
2. View that is directly behind the rear view.
a. Top View
b. Side View
c. Front View
d. Bottom View
3. View directly observed beneath the front view.
a. Top View
b. Side View
c. Front View
d. Bottom View
4. What is the appearance of a line inclined to the plane of projection?
a. appears a point
b. appears as a line or edge
c. appears shorter or foreshortened
d. appears in its exact or true shape and size
5. A surface parallel to the plane of projection will appear as
a. a point
b. as a line or edge
c. shorter or foreshortened
d. in its exact or true shape and size
1. The top view is directly above the front view, the right-side view is directly to the right of the
front view and the rear view is directly behind the front view.

a. Isometric Drawing c. First Angle Projection

b. Orthographic Drawing d. Third Angle Projection
2. The appearance of the object as viewed directly from the above on top is projected.
a. Projection c. Inclined Plane of Projection
b. Frontal Plane of Projection d. Horizontal Plane of Projection

3. This will show the shape of an object when viewed from the side and the distance from the
bottom to top and the distance from front to rear.
a. Projection c. Inclined Plane of Projection
b. Frontal Plane of Projection d. Horizontal Plane of Projection

4. In which two views is the length of the object the same?

a. Front and Top View c. Top and Side View

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 b. Front and Side View d. Side and Rear View

5. In which views is the thickness of the object the same?

a. Front and Top View c. Top and Side View
b. Front and Side View d. Side and Rear View

TEST II
Direction. Answer Set A and B test (Write your answer in a separate sheet of
paper).

A. Enumerate the 3 principal views in the orthographic drawing

1.
2.
3.

B. List down five tools and materials used in constructing orthographic drawing

1.
2.
3.
4.
5.

INFORMATION SHEET #. 2.3.

Dimensioning

Dimensions are indicated in the drawings by dimension lines and numerical figures.
Dimension lines is used to indicate the measurements of objects. The two kinds of dimensions are
size and location dimensions. Size dimension give the detail and overall sizes of the object.
Lcoation dimensions merely locate part or parts of the object. To locate a part, there must be at
least two location dimensions.

Size Dimension Location Dimension

Overall dimensions are shown the total thickness or height, width, and length of an object,
while detail dimensions are the thickness, length, and width of each part of the same object.
Complete dimensioning of any object is necessary no matter how simple or complex it may be.

Dimensioning Rules

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 To help the beginner remember the dimensioning rules, it should be remembered that each
rule is followed by illustration or illustrations. Not included here are rules followed in advance
dimensioning such as limit dimensioning and the dimensioning of weld joints. The foolowing are
the dimensioning rules wikch every draftman should remember:

1. Dimensioning should generally be placed between views.

The areas or spaces between views are indicated by light – shaded line.

Avoid repetition of dimensions.

a. Sound practice b. Unsound practice

2. Dimension lines should be parallel to the edge or line being measured.

This Not This

3. The flare of arrowhead should be properly made. In sketching, an

arrowhead may be made with one heavy stroke of the soft pencil.

Proper Improper
4. The fine line in a dimension line must be strictly observed. It should be
about one – fourth the thickness of the visible line. Its thickness should be
the same as that of the projection line.

This Not This

14
5. The figures or numbers in a dimension line should be legible and properly located.

This Not This

6. Dimensional figures are preferably directional. Unidirectional dimensions may be used if

the company desires them. Never mix directional dimensions in a drawing.

Directional (Preferred for Unidirectional (Practiced in

Beginners) some industrial firms

7. Use an outside dimension if the space is limited, and use an inside dimension if the space is
ample or wide.

Outside Dimension Inside Dimension

8. Only metric measurements should appear in drawings

Good Practice Bad Practice

Note: Use one system of measurement in every drawing

9. Continuous dimensions should be used whenever possible.

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10. Staggered dimensioning should be used when the spaces for the dimensions are narrow.

11. A dimension line may be terminated by a projection, visible, hidden, or center line.

By Projection By Visible Line

By Center Line By Hidden Line

12. Dimension lines should be extended beyond the edge or line being measured. It should
always touch the projection line or edge being measured.

This Not This

13. Arrowheads should point to the terminating line and not to the dimensional figure.

This Not This

14.Let no workman add or subtract dimensions. To put it another way, complete all
dimensions needed.

16
 Preferred Poor Practice

15. When giving the location dimensions for round holes, measure the center – to – center
distance between holes and from the center line of the holes to the two nearest visible lines.

16. Place dimension closest to the part being measured. Dimensions may be placed inside a
view.

Preferred Poor Practice

17. Never crowd dimensions. The dimension closest to a view should be about 7 mm. the other
dimensions could be similarly spaced. Avoid aligning dimensional figure vertically.

This Not This

18. Projection or extension lines should be properly drawn. They should extend about 3 mm
from the dimension line and not closer than 1½ mm from the object or visible line.

This Not This

17
 Self Check #2.3

Dimensioning

Multiple Choice:
Direction: Read and analyze the statement carefully. Choose the best answer and write the
letter only in your answer sheet.

1. This gives the total thickness, width, and length of an object.

a. Dimension Line
b. Size Dimension
c. Overall Dimension
d. Location Dimension
2. Dimensions should be placed
a. between views
b. above the top view
c. below the front view
d. on the right side of the front view
3. Figures or numbers are located
a. after the arrowhead
b. before the arrowhead
c. parallel at the middle of the arrows
d. perpendicular at the middle of the arrows
4. When will you apply outside dimensioning?
a. hidden parts of the object
b. dimensioning on arcs and circles
c. space between edges of the objects are narrow
d. space between edges of the objects are too wide
5. When locating dimension between circles, dimension is placed
a. center-to-edges of circles
b. between endpoint edges of circles
c. between near point edges of circles
d. center-to-center distances between circles
6. Which of the following is preferred rule of dimensioning?
a. b. c. d.

7. What is the problem on dimensioning of the illustrated object?

a. Sizes of the figures are not proportional with the dimension line.
b. Dimension lines are of the same weight with the object line.

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 c. Dimensions too closed to the object lines
d. Free on dimensioning problems.

8. What should be the approximate thickness of dimension lines compared to the object lines?
a. 1/16
b. 1/8
c. 3/16
d. 1/4
9. This is the preferred distances between dimension lines and the object lines.
a. 3 mm
b. 5 mm
c. 7 mm
d. 10 mm
10. What is the distance between the extension lines and the object or visible lines?
a. 1.0 mm
b. 1.5 mm
c. 3.0 mm
d. 4.0 mm

INFORMATION SHEET No. 2.4

Scaling

Scaling is the process of making an object shorter or longer, bigger or smaller so that it
could be conviniently drawn on paper.

Rules used by pattern makers in a foundry shop are scaled to compensate for the
expansion and contraction of materials for casting. Also, the rules, traingular in cross-section, used
by architects and engineers you might have seen around, are scaled to make buildings, highways
and amchineries shorter or smaller for accomodation on drawing paper.

The rule below is an architectural or mechanical engineer’s rule. Reduction in size is based
on proportion of the millimeters.

Methods of Scaling

1. Reducing Method. This method is applied when the object to be drawn is bigger than
the size of the gragihng paper where to draw. This is most practiced method of scaling
for engineering works.

Example:
a. Scale 1 : 100 mm
b. Scale 1 : 500 mm

19
2. Enlarging Method. The object to be drawn is too small for the size of the graphing
paper. This needs the object to be enlarge that is proportional to the size of the graphing
paper.

Example:
a. Scale 10 : 1 mm
b. Scale 100 : 20 mm

3. Retaining Method. The object to be drawn need not to be alter to be proportional to the
graphing paper.

Example:
a. Scale 1 : 1

The scale size of a drawing is always in direct proportion to the actual size of the object.
The figure on the left side represents the quantity of measure for the drawing while the figure on
the right side represents the corresponding quantity of measure for the object being illustrated.

Example:

a. Scale 1:100 is used and the dimension of the object is 10 meters. The linear distance
on the print, therefore, is 0.1 meter of the object distance.

1 x 10 m = 0.1 m
100

b. What is the linear distance in the blueprint of a 10.0 meters distance if the scale applied
is 1:400?

Scale 1:300

1 x 10.0 m = 10.0
400 400

= 0.025 m or 2.5 cm

Activity Sheet 2.4

Scaling

Direction: Give the true lengths of the given dimensions using the following scales.

1. 3.0 m scaled to 1:100

2. 5.25 m scaled to 1:300

3. 125 cm scaled to 1:50

4. 250 cm scaled to 1:400

5. 7.5 m scaled to 1:1000

20
 6. With the architectural rule, measure the following lines and give the true lengths
according to scales 1:500

a.

b.

c. ______________________________________________

Program/Course: Shielded Metal Arc Welding (SMAW) NC 1

Unit of Competency: Interpret Drawing and Symbols
Module Title: Interpreting Drawing and Symbols

Learning Outcome 3: Interpret Standard drawing Symbols, Dimensional

Tolerances and Notations
INTRODUCTION

This lesson covers the knowledge skills and attitude required for interpreting
standard drawing symbols, dimensional tolerances and notations according to
specification.

Assessment Criteria:

1. Drawing symbols are interpreted according to drawing standards.

2. Dimensional tolerance, notations are interpreted according to specifications.

Definition of Terms

Weld Joints- refers to how the parts to be welded are assembled prior to welding

Weld Symbols-miniature drawing of the metal edge preparation prior to welding. Provide the
means of placing complete welding information on drawings.

Supplementary Symbols- are symbols that provide additional requirements or instruction

INFORMATION SHEET 3.1

Interpret Standard Drawing Symbols, Dimensional Tolerances and Notations

Welding Symbol

Location of Elements: The elements of a welding symbol have standard locations with respect to each
other.

Location Significance of Arrow: The arrow element in a welding symbol in conjunction with the reference
line determines the arrow side and other side of a weld.

The symbol depicting an arrow side weld is always placed below the reference line. The arrow side is
always closest to the reader when viewed from the bottom of the drawing. The weld symbol depicting

21
other side weld is placed above the reference line, away from the reader. Welds on both side of a joint are
shown by placing weld symbols on both sides of the reference line.

Some weld symbols have no arrow or other side significance. However, supplementary symbols used in
conjunction with these weld symbols may have such significance. For example, welding symbols for
resistance spot and seam welding have no side significance, but GTAW, EBW, or other spot and seam
welds may have arrow and other side.

References: When a specification, process, test, or other references is needed to clarify a welding symbol,
the reference is placed in a tail on the welding symbol. The letters CJP may be used in the tail of the arrow
to indicate that a complete joint penetration groove weld is required, regardless of the type of weld or joint
preparation. The tail may be omitted when no specification, process, or other reference is required with a
welding symbol.

Dimensions: Dimensions of a weld are shown on the same side of the reference line as the weld symbol.
The size of the weld is shown to the left of the weld symbol, and the length of the weld is placed on the
right. If a length is not given, the weld symbol applies to that portion of the joint between abrupt changes
in the direction of welding or between specified dimension lines. If a weld symbol is shown on each side
of the reference line, dimensions are required to be given for each weld even though both welds are
identical.

Either US Customary or SI units may be used when specifying dimensions. However, only one of the two
should be used for a product or project.

If a weld in a joint is to be intermittent, the length of the increments and the pitch (center-to-center
spacing) are placed to the right of the weld symbol.

The term weld symbol and welding symbol have different meanings. A weld symbol indicates the
required type of weld. The welding symbol includes the weld symbol and supplementary information. A
complete welding symbol consists of the following elements:

 Reference line
 Arrow
 Basic weld symbol
 Dimensions and other data
 Supplementary symbol
 Finish symbol
 Tail
 Specification, process and other references

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F – Finish Symbol
A – Groove Angle: included angle of countersink for plug welds
R – Root Opening; depth of filling for plug and slot welds.
S – Depth of Bevel: size or strength for certain welds
E – Groove Weld Size
L – Length of Weld
P – Pitch of Weld: center-to-center spacing
T – Tail of Weld: specification, process of other reference (omitted when reference is not used
N – Number of Spot, Stud, or Projection Welds

- Field Weld

- Weld All Around

- Contour Symbol

In your work, you may be required to work from these drawings; therefore you should
understand the use and meaning of these symbols.

MEANING & USE OF SYMBOLS

An arc welding symbol consists of the main four parts

1. A reference line
2. An arrow.
3. A basic welding symbol
4. A tail

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The basic symbol indicates the type of weld.

(Butt, fillet, etc.)

1. The reference line is a line connected to the arrow. The position of the basic symbol above or
beneath this line determines the location of the weld. The reference line is always drawn
parallel to the bottom edge of the drawing, or to the base line of a particular view.

2. The arrow indicates the position of the weld; it is drawn at an angle from the
end of the reference line to one side of the joint. This side is called the ‘arrow
side of the joint’. The opposite side is called the other side of the joint.

Arrow Location

Welds on the ‘arrow side of the joint’ are shown by inverting the weld symbol and placing it
beneath the reference line.

24
 Symbol Indicating Fillet Weld
At Arrow Side of Joint

1. Welds on the ‘other side of the joint’ are shown by placing

the symbols above the reference line.

Symbol indicating fillet welds on the other side of joint.

2. Welds on both sides of the joint are shown by placing the

weld symbol above and below the reference line.

Fillet weld both sides of the joint

3. Basic weld symbols describe the type of weld to be made. This symbol is a miniature drawing
of the metal’s edge preparation prior to welding. The basic weld symbol is only part of the
entire AWS welding symbol.

Form of Weld Weld Symbol Sectional Representation

Bead

Fillet

Square Butt

25
 Single V Butt

Single Bevel Butt

Single U Butt

Single J Butt

Double V Butt

Double U Butt

Plug and Slot

Stud

Surfacing

4. The tail is added to the symbol only when special notes are required. A number or letter code
used inside the tail direct the welder to special notes located elsewhere on the drawing. These
notes may specify the heat treatment, welding process used, or other information not given on
the welding symbol.

26
 Self – Check # 3.1

Welding Symbols

Multiple Choice:
Direction: Read and analyze the statement carefully. Choose the best answer and write the letter
only in your answer sheet.

1. This is information used as a guide by the welder in constructing or assembling metal products.
a. Drawings c. Weld Symbols
b. Sketches d. Welding Symbols
2. When a dark triangle (flag) is placed as a typical part of the welding symbol, this means that
a. the project must have to be made
b. the project is to be made on site
c. the project is to be made on shop
d. the project is to be made as the need arises
3. Reference line is known to be as __________ of the welding symbol.
a. main part c. longest part
b. primary part d. main and longest part
4. Parts of the welding symbol used to indicate position of the weld.
a. Reference Line c. Arrow
b. Weld Symbol d. Tail
5. The symbol triangle attached to the reference line indicates the type of weld.
a. Bead c. Square Butt Weld
b. Fillet d. Single V Butt Weld
6. This type of weld attached below the reference line indicating that the weld is to be made.
a. Arrow side of the joint b. Both sides of the joint
b. Other side of the joint c. None of the above
7. What is the purpose of surfacing symbol?
a. apply stringer bead c. building-up the surface
b. filling-up the surface d. all of the above
8. When special notes are required for the welder be informed, part of the welding symbol is
indicated.
a. Reference Line c. Arrow
b. Weld Symbol d. Tail
9. Basic weld symbol is only a part of the welding symbol indicating the
a. position of the weld c. size of the weld
b. types of weld d. especial notes required
10. This symbol is a miniature drawing of the metal’s edge preparation prior to welding.
a. Reference Line c. Arrow
b. Weld Symbol d. Tail

INFORMATION SHEET 3.2

Supplementary Symbols

Supplementary symbols can be placed above or below the basic symbol, or at the intersection
of the reference line and the arrow. Dimensions and reference to specifications, or welding procedures
may also be added.

1. Weld all around is a circle drawn on the welding symbol, indicating that the described weld is to
be made all around the part.

27
2. Field weld symbol is a symbol added to the basic AWS welding symbol to indicate that a weld is
to be made at the job site (“ in the field”), rather than in a fabricating shop.

3. Melt through is a complete joint penetration for a joint welded from one side and visible root
reinforcement is produced.

4. Backing symbol is an open rectangular box used in combination with a groove weld symbol
located on the reference line indicating that locating materials is required on the opposite side
control penetration.

5. Spacer symbol is an open box that intersects the reference line, indicating that a spacer is placed
between joint.

Contour and Finish Symbol

1. Flush contour symbol is located on the same side as the symbol and indicates the weld should be
approximately a flat plane with the surface.

2. Convex contour symbol is located on the side as the symbol and indicates that the weld should be
raised or convex shape.

3. Concave contour symbol is located on the same side as the symbol indicates that the weld should
be concave shape.

4. If the contour requires finishing, a finishing symbol will be sued in conjunction with the contour
symbol, a letter G indicate grinding, C indicate shipping, M indicate machining, and U indicate
unspecified which local method should be used.
Self – Check 3.2

28
 Supplementary Symbols

Multiple Choice:
Direction: Read and analyze the statement carefully. Choose the best answer and write the letter
only in your answer sheet.

1. This symbol indicating that the joint/welds cannot be made in the shop but rather it will be made
on site.
a. Weld all around c. melt through
b. Field weld symbol d. spacer
2.Melt through symbol shows that the required output of welding should be
a. visible face reinforcement c. burn through
b. visible root reinforcement d. penetration
3.Weld all around symbol is mostly applied on welded joints like
a. Pipe welded to similar diameter of pipe
b. Plate welded to plate with the same thickness
c. Pipe welded to plate
d. All of the above
4.Backing symbol is required to a butt joint.
a. Square butt joint c. Double V butt joint
b. Single V butt joint d. Double bevel butt joint
5.This symbol is required to control the penetration on the opposite side of the joint.
a. Melt through c. Backing symbol
b. Finish symbol d. Spacer
6.What finish symbol should be included when it requires 2-3 mm weld reinforcement above the
surface of the base metal?
a. finishing symbol c. convex contour symbol
b. flush contour symbol d. concave contour symbol
7.What should be included in the welding symbol when the welded joint requires grinding?
a. finishing symbol c. convex contour symbol
b. flush contour symbol d. concave contour symbol
8.The appearance of the weld profile with the flush contour symbol included in the welding
symbol is
a. weld is underfill
b. weld should be grinded
c. weld raised above the surface of the base metal
d. weld is approximately flat with surface of the base metal
9.When concave contour symbol is located on the same side as the weld symbol, this indicates that
a. weld is underfill
b. weld should be grinded
c. weld should be raised above the surface of the base metal
d. weld is approximately flat with surface of the base metal
10.Melt through is included in the welding symbol indicating that
a. weld size is enough
b. weld is burn through
c. c. penetration is too much
d. d. accepted joint penetration

29
 INFORMATION SHEET # 3.3

Typical Welding Symbols

Information given on the welding symbol must always be shown in the designated location
on the symbol. These locations are determined by the side of the reference line on which the weld
symbol is placed.

Weld Symbols

Weld symbols are intended to be based in conveying the information among the designer, shop and
fabrication personnel.

 Type of joint
 Type of joint preparation
 Side of groove preparation and welding
 Type of weld
 Size of weld

a. Type of Joint
A joint is a junction of members or the edges of members that are to be joined or have been joined.
The five basic joints used in welding are:

A. Fillet weld

Dimension of fillet welds are shown on the same side of the reference line as the weld
symbol and are shown to the left of the symbol. When both sides of a joint have the same size fillet
welds, one or both may be dimensioned. When both sides of a joint have different size fillet welds,
both are dimensioned. When the dimensions of one or both welds differ from the dimensions given
in the general notes, both welds are dimensioned. The size of a fillet weld unequal legs is shown in
parentheses to the left of the weld symbol. The length of a fillet weld, when indicated on the
welding symbol, is shown to the right of the weld symbol. In intermittent fillet welds, the length
and pitch increments are placed to the right of the weld symbol. The first number represents the
length of the weld, and the second number represents the pitch or the distance between the centers
of two welds.
A.1 Equal Leg Fillet Weld – Both Sides

A.2.Equal Leg Chain Intermittent – Both Sides

30
 A.3. Staggered Intermittent Fillet Weld

B. Groove Weld

In groove weld preparation, the root opening is given inside the weld symbol. The groove angle is
shown just outside the weld symbol. The depth of penetration is given on the left side of the
welding symbol. Weld size may also be given in this same location.

Edges of metal over ¼” (6.4 mm) thick are always prepared in some way before making a groove
weld, in order to ensure 100% penetration. The groove weld size is the depth to which a weld
penetrates the joint from the surface of the base metal. The desired depth of preparation and the
depth of the weld penetration are generally determined by codes or specifications.
.

Plate Thickness = 3/8“

Depth of Groove =1/4”
Weld Size = 3/8“
Groove Angle = 600
Root Gap = 1/8“

B.1. Square Butt Groove

Closed Square Butt Groove Double Open Square Butt Groove

Weld Size = 1/4”

Weld Size =1/4”
Closed Butt Groove = No Gap

31
 Root Gap = 1/8”

B.2 Single Vee Groove

C. Plug Welds

Holes in the arrow side member of a joint for plug welding are indicated by placing the
weld symbol below the reference line. Holes in the other side member of the joint for plug welding
are indicated by placing the weld symbol above the reference line. Refer to the figure for the
location of the dimensions used for plug welding.

The diameter or size is located to the left of the symbol (A). The angle of the sides of the
hole, if not square, is given above the symbol (B). The depth of build-up, if not completely flush
with the surface, is the given in the symbol (C). The center-to-center dimensioning or pitch is
located on the right of the symbol (D).

32
 Self – Check.3.3

I. Multiple Choice:

Direction: Read and analyze the statement carefully. Choose the best answer and write the letter only in
your answer sheet.

1.This is information used as a guide by the welder in constructing or assembling metal

products.
a. Drawings c. Weld Symbols b. Sketches d. Welding Symbols
2.Parts of the welding symbol used to indicate position of the weld.
a. Reference Line c. Arrow b. Weld Symbol d. Tail
3.The symbol triangle attached to the reference line indicates the type of weld.
a. Bead c. Square Butt Weld b. Fillet d. Single V Butt Weld
4.When special notes are required for the welder to be informed, part of the welding
symbol is indicated.
a. Reference Line c. Arrow b. Weld Symbol d. Tail
5. This symbol is a miniature drawing of the metal’s edge preparation prior to welding.
a. Reference Line c. Arrow b. Weld Symbol d. T
6. It’s indicated by placing the weld symbol below the reference line.
a. Plug weld b. Fillet weld c. Square Butt Groove d. Single Vee Groove
7. The root opening is given inside the weld symbol.
a. Groove weld b. Fillet weld c. Square Butt Groove d. Single Vee Groove
8. Located on the same side as the symbol and indicates the weld should be approximately a flat plane
with the surface.
a. Flush contour symbol c. Concave contour symbol
b. Convex contour symbol d. Finishing symbol

9. Located on the side as the symbol and indicates that the weld should be raised or convex shape.

a. Flush contour symbol c. Concave contour symbol

b. Convex contour symbol d. Finishing symbol

10. Located on the same side as the symbol indicates that the weld should be concave shape.
a. Flush contour symbol c. Concave contour symbol
b. Convex contour symbol d. Finishing symbol

POST TEST
Multiple Choice:
Direction: Read and analyze the statement carefully. Choose the best answer and write the letter
only in your answer sheet.

1. This is information used as a guide by the welder in constructing or assembling metal products.
a.Drawings c. Weld Symbols
b. Sketches d. Welding Symbols
2.When a dark triangle (flag) is placed as a typical part of the welding symbol, this means that
a. The project must have to be made
b. The project is to be made on site
c. The project is to be made on shop
d. The project is to be made as the need arises
3.Reference line is known to be as __________ of the welding symbol.
a.main part c. longest part
b.primary part d. main and longest part
4.Parts of the welding symbol used to indicate position of the weld.
a.Reference Line c. Arrow
33
 b.Weld Symbol d. Tail

5.The symbol triangle attached to the reference line indicates the type of weld.
a. Bead c. Square Butt Weld
b. Fillet d. Single V Butt Weld
6.This type of weld attached below the reference line indicating that the weld is to be made.
a. Arrow side of the joint c. Both sides of the joint
b. Other side of the joint d. None of the above
7.What is the purpose of surfacing symbol?
a. apply stringer bead c. building-up the surface
b. filling-up the surface d. all of the above
8.When special notes are required for the welder be informed, part of the welding symbol is indicated.
a. Reference Line c. Arrow
b. Weld Symbol d. Tail
9.Basic weld symbol is only a part of the welding symbol indicating the
a. position of the weld c. size of the weld
b. types of weld d. especial notes required

10. This symbol is a miniature drawing of the metal’s edge preparation prior to welding.
a. Reference Line c. Arrow
b. Weld Symbol d. Tail
11. Fine lines with arrowheads usually touch the extension lines and show distance given by the
dimensions.
c. Hidden Lines c. Extension Lines
d. Dimension Lines d. Cutting Plane Lines

12. The purpose of this line is to indicate where an imaginary cut is made through the object.
c. Hidden Lines c. Extension Lines
d. Dimension Lines d. Cutting Plane Lines
13. Series of fine lines-solid or solid and broken arranged in specific patterns used to represent various kinds of
materials.
c. Chain Line c. Section Line
d. Break Line d. Phantom line

14. Fine lines that extend from the object with a slight break between and it is used to show dimensioning points.
c. Chain Line c. Section Line
d. Object Line d. Extension Line

15. Used to show the visible shape of the object.

c. Chain Line c. Section Line
d. Object Line d. Extension Line

16. Ruled, light line with freehand zigzags used to show a long break to conserve
spaced on a drawing.

a. Chain Line c. Section Line

b. Long Break Line d. Phantom line

17 . Heavy, irregular line drawn freehand used to show a short break to conserve
space on a drawing.

a. Short Break Line c. Section Line

b. Long Break Line d. Phantom line

18 . Fine, broken line made up of a series of short and long dashes alternately
spaced.

a. Center line c. Extension Lines

34
 b. Dimension Lines d. Cutting Plane Lines
19. Broken line of medium thickness and used to show the edges and outlines not
visible to the eye.
a. Hidden lines c. Extension Lines
b. Dimension Lines d. Cutting Plane Lines

20 . Light, broken line made up of a series of long and two short dashes used to show
alternate positions of a part
a. Phantom line c. Section Line
b. Long Break Line d. Short Break Line

References
 Welding Technology, Second Edition by Gower A. Kennedy

 Welding Inspection Technology, Education Department, American welding

Society

 Welding Principles and Application by Larry Jeffus and Harold V. Johnson

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