Drafting

1. By: IST
DRAFTING

2. FOUR COMMON TERMS
 Drawing
 International language
 Freehand drawing/sketching
 Paper and pencil
 Mechanical drawing
 With instruments such as T-sqaure,
triangles
 Orthographic projection
 Exact shapes and observation

3. METHODS OF DRAWING LINES
A. Orthographic
 Also called as 3 VIEW DRAWING
 Planes of porjection
 Frontal Plane Front View
 Horizontal Plane Side View
 Profile Plane Top View
 Glassbox technique
 Extracting or extraction of TV, SV and FV

4. B. Pictorial
1. Isometric
 3 Dimensional, 30 degrees, 30 x 60 degrees, triangle
2. Perspective
 Most realistic, visual observation
o Bird’s Eye View (becomes narrower)
o Man’s Eye View (horizontal plane)
o Worm’s Eye View (becomes bigger)
3. Oblique
 One side is parallel to another, 45 degrees
o Cavalier – actual measurement
o Cabinet – depth reduce to ½
o General – depth reduce to ¼

5. OVERALL
SEMI-
DETAILED
TWO KIND OF DIMENSION
• Location Dimension – parts, size, shapes
• Detailed Dimension
 Overall – width, length, height
 Semi-detailed – minor measurements

6.  H – Hardness
 B – Softness

7. Grades of Pencil
Soft – 2B, 3B, 4B, 5B, 6B
(softest)
Medium – 3H, 2H, H, F, HB, B
Hard – 4H, 5H, 6H, 7H, 8H, 9H
(hardest)

8. Note: for lettering, find the choices where HB is
included (ex. A. HB, B or 2H 4H
Grades of Pencil used for
General Drafting
HB – for lettering
2H – for line work
4H – for general

9. Minimum requirement for drafting
students
4H – for repenciling F or H – for all
lettering and freehand work
6H – for light construction lines
2H – for visible object lines

10. GEOMETRIC FIGURES
1.LINE
Set of points
Types of Lines
 Straight line – shortest distance between
two points
 Parallel line – will never meet
 Perpendicular line – intersecting lines

11. 2. Kinds of Angles
 The simplest way to sort triangles is
by their angle size:
 Acute triangle is one in which all the angles are acute
(less than 90°).
 Obtuse triangle is one in which one of the angles is
obtuse (more than 90°).
 Right triangle is one in which one of the angles is a
right angle (exactly 90°).

12. Another way to group triangles is by
looking at the lengths of their sides:
Equilateral triangle is one in which all
three sides have the same length.
Isoceles triangle is one in which two
sides have the same length.
Scalene triangle is one in which all
three sides have different lengths

13. 3. POLYGONS

14. To convert inches to meters, follow the
conversion table below.
1 inch 0.025 meter
2 inches 0.050 meter
3 inches 0.075 meter
4 inches 0.10 meter

15.  PROPORTION OF LETTERS
1. Normal letters – used when space is
adequate
2. Extended letters – used when space
is wider
3. Compressed letters – used when
space is limited
4. Lightface – with very thin stems
5. Boldface – having heavy stems

16. Guidelines

17. Roman
(thick and thin lines)

18. Gothic
(uniform width)

19. Italic Letters
(slant)

20. Script Letters
(cursive)

21. Text Letters
(fancy style of letters)

22. TYPE OF LINES
 Break line (long – wavy, and short – pointy)
 Cutting plane line
Cutting plane line

23.  Visible line
 Hidden line
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
 Center line
________ __ ________ __ ________
 Extension line
__________ __________
 Dimension line
Fine line Figure Arrowhead
2.00

24.  Types of Section
1. Full section – cuts entirely across
2. Half section – symmetrical
3. Broken-out section – partial used when need
exposure
4. Revolved section – show true shape
5. Removed or Detailed section – same as revolved
but not shown on view
6. Phantom section or Hidden section – emphasized
interior