PRIN. OF DRAFTING AND SHOP DRAWINGS - OD1641 - LESSON 1/TASK 1
(c) Diagrammatic.
Usually made for the purpose of locating and setting up
projects.
b. Equipment and Materials.
In the following paragraphs, some of the materials
required to make a good sketch of an object will be discussed.
(1) Paper.
Either plain or cross-section (grid) will be used.
(2) Pencil.
Medium, sharpened to a long conical point, not too sharp.
(3) Eraser. Art gum or regular, but to be used only when a clean, clear job can
be accomplished.
(4) Measuring Devices.
(a) Rule or scale
(b) Calipers
(c) A square, thread gage, and micrometer, on occasions where more accurate
sketches are required.
c. Technique. In drawing any straight line between two points, keep the eyes on
the point to which the line is to go rather than on the point of the pencil. Do
not try to draw the complete line in a single stroke. Usually, it is advisable to
draw a light line first, and then correct any discrepancies in the light line with
a heavy line. Accuracy of direction is more important than the smoothness of the
line. To obtain this accuracy, hold the pencil freely, not too close to the point,
and draw the different lines as follows:
(1) Vertical Lines.
Draw
downward
with
a
finger
movement
in
a
series
of
overlapping strokes.
(2) Horizontal Lines.
Draw with either a wrist or forearm motion.
(3) Inclined Lines. When running downward from right to left, draw with the same
motion used for vertical lines.
When they run downward from left to right, turn
the paper and draw them as horizontal lines.
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