CHAPTER 2
DRAFTING EQUIPMENT
Drawing is often called the universal language.
Drafting is the particular phase of drawing that
engineers and designers use to convey and record
ideas or information necessary for the con-
struction of structures and machines. There are
definite rules of usage to ensure that the same
meaning is conveyed at all times and to enable
those who learn the rules to interpret what is
presented in a drawing. In contrast to pictorial
drawings, such as paintings of landscapes and
living things, engineering drawings use a graphical
language to describe every integral part of an
object. As an Engineering Aid, you will specialize
in engineering drawings, whereas the Illustrator
Draftsman will specialize in pictorial drawings.
In studying this chapter, you will learn that
drafting is classified into types, such as technical,
illustrative, mechanical, freehand, and engineering
drafting. Then you will go on to learn about
charts, graphs, drafting guidelines, and a variety
of instruments and materials, all of which are
designed to help you perform your drafting duties.
This chapter also contains many pointers that will
help you operate, adjust, and maintain your
drafting instruments.
TYPES OF DRAFTING
Generally, drafting is classified according
to its purpose or the means by which it is
accomplished.
TECHNICAL AND
ILLUSTRATIVE DRAFTING
A distinction is often made between technical
drafting and illustrative drafting. TECHNICAL
DRAFTING presents technical information in a
graphic form; for example, a drawing that shows
the type and proper placement of structural
members in a building. ILLUSTRATIVE DRAFT-
ING presents a pictorial image only; an example
is a perspective drawing of a proposed structure.
The term illustrative drafting
used in construction drafting.
MECHANICAL AND
FREEHAND DRAFTING
is not commonly
MECHANICAL DRAFTING, as distin-
guished from freehand drafting, is any drawing
in which the pencil or pen is guided by mechanical
devices, such as compasses, straightedges, and
french curves. In FREEHAND DRAFTING the
pencil or penis guided solely by the hand of the
draftsman. Sketches are the result of freehand
drafting. With the exception of lettering, most
technical drafting is mechanical drafting in this
sense of the term.
In a different sense, the term mechanical
applies to certain types of industrial or engineering
drawings, regardless of whether the drawings are
done mechanically or freehand. Some authorities
confine the term, used in this sense, to the
drawing of machinery details and parts. Others
confine it to the drawing of plumbing, heating,
air conditioning, and ventilating systems in
structures. In the SEABEEs, mechanical drawing
means the arrangements of machinery, utility
systems, heating, air conditioning, and ventilating
systems.
ENGINEERING DRAFTING
As an Engineering Aid, you will be primarily
concerned with the following broad types of
engineering drafting:
1. Topographic drafting, or drafting done in
connection with topographic and civil engineering
surveys. It may include drawings not directly
related to topographic maps, such as plotted
profiles and cross sections.
2. Construction drafting, or drafting of
architectural, structural, electrical, and
mechanical drawings related to structures.
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