Transcript SECTION DRAWINGS

SECTION DRAWINGS
SECTION DRAWINGS
A section drawing shows detail on
the inside of an object by cutting
away part of the object.
FULL SECTION
Q: Why do we call this a “Full” section?
FULL SECTION
A: The cutting plane line cuts through the entire length,
height, or width.
CUTTING PLANE LINES
•Cutting plane lines mark the point at which the object is to be
cut apart (wide dashed line .7mm thick).
Sight lines point to the part of the object that is to be kept.
CUTTING
PLANE LINE
SIGHT LINE
HATCHING
Hatching is used to show where the object has been cut. In
other words, if the part was cut with a saw, the hatching would
represent where the saw actually touched the object as it was
being cut.
Hatch lines (.3mm)
The pattern of the hatching used represents different types of
materials. In the case above, a generic hatch has been used.
This generic hatch is sometimes used to represent iron or steel.
Hatch lines should match the color of the cutting plane line.
HATCH PATTERNS
FULL SECTION
No hidden lines on the sectional portion of a view
HALF SECTION
HALF SECTION
Q: Why do we call this a
“HALF” section?
HALF SECTION
A: The cutting plane line cuts
through only “Half” the length,
height, or width of the object.
HALF SECTION
This line divides the object so
the sectioned portion and the
non-sectioned portion can be
defined.
OFFSET SECTION
OFFSET SECTION
Offset sections allow one cutting plane line to transect
multiple areas of a part. This reduces the amount of work
needed to complete a drawing.
OFFSET SECTION
Notice that there isn’t a line added to show where the offset
portion of the cutting plane line changes direction.
BROKEN-OUT
SECTION
Notice that there isn’t a cutting
plane line on this style of section
drawing.
Instead, a broken-out section
line is used. (.7mm line)
This style is used when a part is
fairly symmetrical.
REVOLVED SECTION
A revolved section is used to show the profile of a part in
another view.
In this case an “I” beam is shown from an angle that
emphasizes its length. By breaking-out the center area and
placing a side view in-line with the view, a sense of what
this part actually looks like is better communicated.
BREAK LINES
Break Lines (.3mm)
Break lines are used when a long object that would
otherwise not fit on a standard sized drawing is shortened.
This can only be done on an object that is very regular. The
picture above is of an “I” beam that is over 10’ long. It has
been shortened using break lines so it can fit on an A-sized
sheet of paper.