Engineering Graphics & Design Sectional Views Engineering Graphics & Design By John Kirby

Sectional Views Cut into the drawing Reduce confusion of excessive hidden lines Hatch lines represent the interior mass Aid visualizing the internal workings of a drawing

Alphabet of Lines

Crosshatching Crosshatching patterns represent the various metals and materials used in Engineering Graphics & Design.

Acceptable styles for cutting plane lines Full Sections Cuts the drawing completely apart Cuts generally horizontal or vertical from one end to the other Cuts often pass through the center of the drawing Acceptable styles for cutting plane lines

Full Section Part Outline – heavy weight line Cutting Plane Line Crosshatching Cutting Plane line for full section is cut through the center of the top view. Cutting plane lines represent imaginary cuts through the object to see interior shapes. Crosshatching is drawn with thin lines at a 45 degree angle. The crosshathing selected is ansi131. This hatching represents iron or general purpose material. When the section line cuts the object is rotated to see interior shapes. The edges of the cuts are represented with heavy weighted lines and not hidden lines.

Half Sections A half section is one half of a full section ¼ of the object is cut Two cutting plane lines at right angles ½ of the view is represented by the cut Used when drawing symmetrical objects

Half Sections of 4 Step Pulley Part Outline – heavy weight line Note that ¼ of the top view is cut by the cutting plane line but ½ of the part is represented by the section view to the right. Half Section– cutting plane line drawn at right angle

Offset Sections Cutting plane lines are shifted to include missing details Cutting plane lines only view areas along the cutting plane line Cutting plane lines are offset to include more details

Offset Section Cutting Plane line does not include holes behind the line. Offset Cutting Plane line does includes holes along the line.

Break Out Sections Removes a defined area of material Exposes obscured parts or features in an existing drawing view View must be associated to a sketch that contains the profile defining the break out boundary

Break Out View of Part Break Out View exposes inside of part with counter bore with threaded hole

Break Out View of Assembly Drawing A Break Out View can also be utilized on assembly drawings to view inside of assemblies.

Detail View Represents a specified portion of a view Assigning any scale to the view Used a zoom to enlarge areas better represented by enlarging for clarity

Detail View of Box Assembly Box Assembly is drawn ½ scale where the detail view is drawn full scale. Dimensions included on Detail B.

Detail View of a Break Out View

Broken View Used when the component view exceeds the length of the drawing Used when scaling the component view to fit the drawing makes the component view prohibitively small Used view contains large areas of nondescript geometry

Broken View of an Assembly Drawing Break Lines inserted to reduce the actual length of the assembly. Dimension line above also denotes the break. Can you identify and label the other three types of lines used in the drawing?

Auxiliary View Helper view that aligns with the view from which it is projected Are used when true orthographic projections would distort the true shape of the object Are aligned with the projection lines of the auxiliary view

Three View Projection without Auxiliary View Representation The top and right side views do not truly represent the actual shape of the part.

Auxiliary View with Detail Section Projected View aligns with Detail B to insure a true shape of the part.

Auxiliary View with Projected Details for Clarity

Exceptions for Clarity Full Section Offset Section Which view best represents the pulley?

Can you identify the two types of sections used below? A half section A break out section

What type of drawing is illustrated below? Multiview drawing with isometric

What type of section view is represented below? Full Section

What type of section is represented below What type of section is represented below? When is this type of view used? Broken View It is used for long shapes that are broken to reduce their size to fit onto drawing sheets.

What type of view is represented below? When is this technique applied? This is a breakout view. It is applied to show internal sections of a view without using full, half, or offset. This can be used to clarify material used and actual internal shape descriptions.

There are two drawing techniques mentioned earlier in the drawing below: Identify each and explain. Section A-A is a full section. Detail B is a detail section that scaled the detail 2:1 for further clarity of the shape and material.

Identify the type of cutting plane below: Why was it used in this drawing? Offset The pulley would otherwise be distorted in the view.