When you enter a new occupation, you must learn
the vocabulary of the trade in order to understand your
fellow workers and to make yourself understood by
them. Shipboard life requires that Navy personnel learn
a relatively new vocabulary. The reasons for this need
are many, but most of them boil down to convenience
and safety. Under certain circumstances, a word or a
few words mean an exact thing or a certain sequence of
actions, making it unnecessary to give a lot of
explanatory details. A great deal of the work of a
technician is such that an incorrectly interpreted
instruction could cause confusion, breakage of
machinery, or even loss of life. Avoid this confusion and
its attendant danger by learning the meaning of terms
common to drafting. This glossary is not all-inclusive,
but it does contain many terms that every craftsman
should know. The terms given in this glossary may have
more than one definition; only those definitions as
related to drafting are given.
ALIGNED SECTIONA section view in which some
internal features are revolved into or out of the plane
of the view.
ANALOGThe processing of data by continuously
ANGLEA figure formed by two lines or planes
extending from, or diverging at, the same point.
APPLICATION BLOCKA part of a drawing of a
subassembly showing the reference number for the
drawing of the assembly or adjacent subassembly.
ARCA portion of the circumference of a circle.
ARCHITECTS SCALEThe scale used when
dimensions or measurements are to be expressed in
feet and inches.
AUXILIARY VIEWAn additional plane of an
object, drawn as if viewed from a different location.
It is used to show features not visible in the normal
AXISThe center line running lengthwise through a
AXONOMETRIC PROJECTIONA set of three or
more views in which the object appears to be rotated
at an angle, so that more than one side is seen
BEND ALLOWANCEAn additional amount of
metal used in a bend in metal fabrication.
BILL OF MATERIALA list of standard parts or raw
materials needed to fabricate an item.
BISECTTo divide into two equal parts.
BLOCK DIAGRAMA diagram in which the major
components of a piece of equipment or a system are
represented by squares, rectangles, or other
geometric figures, and the normal order of
progression of a signal or current flow is represented
BLUEPRINTS Copies of mechanical or other types
of technical drawings. Although blueprints used to
be blue, modem reproduction techniques now
permit printing of black-on-white as well as colors.
BODY PLANAn end view of a ships hull, composed
of superimposed frame lines.
BORDER LINESDarklines defining the inside edge
of the margin on a drawing.
BREAK LINESLines to reduce the graphic size of
an object, generally to conserve paper space. There
are two types: the long, thin ruled line with freehand
zigzag and the short, thick wavy freehand line.
BROKEN OUT SECTIONSimilar to a half section;
used when a partial view of an internal feature is
BUTTOCK LINEThe outline of a vertical,
longitudinal section of a ships hull.
CABINET DRAWINGA type of oblique drawing in
which the angled receding lines are drawn to
CANTILEVERA horizontal structural member
supported only by one end.
CASTINGA metal object made by pouring melted
metal into a mold
CAVALIER DRAWINGA form of oblique drawing
in which the receding sides are drawn full scale, but
at 45° to the orthographic front view.