PRIN. OF DRAFTING AND SHOP DRAWINGS - OD1641 - LESSON 1/TASK 1
This is called a mitre line. Project the top view of point 1 into the right side
view zone.
This is done by drawing a horizontal construction line to the right,
parallel to the principal plane line until it touches the 45, mitre line. When the
projection line touches the mitre line, it turns the corner, i.e., it goes from
horizontal to vertical.
To continue the projection line, draw a vertical
construction line, parallel to the vertical principal plane line, extending down
into the right side view zone. As before, don't be stingy with the lead; draw the
projection line through and beyond the horizontal projection line.
The
intersection of the two projection lines is the right side view of point 1. Label
it.
Several additional points should be made before leaving this problem. The location
of the front view of point 1 in relation to the top view is not random.
The
vertical line between the front and top views is parallel to the vertical principal
plane line. Figure 8 shows three views of point 1 and the projection lines used to
go from view to view.
The point views and lines form a perfect rectangle (four
sided figure with four right angles).
This projection rectangle enables the
draftsman to find any third view of a point when he is given the two other views.
This means that if we consider only three principle views (top, front, and right
side), there are only three possible projection problems.
FIGURE 8.
PROJECTION RECTANGLE.
8
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