AUXILIARY VIEWS C H A P T E R N I N E Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 1
OBJECTIVES 1. Create an auxiliary view from orthographic views. 2. Draw folding lines or reference-plane lines between any two adjacent views. 3. Construct depth, height, or width auxiliary views. 4. Construct partial auxiliary views. 5. Create auxiliary section views. 6. Produce views to show the true length of a line, point view of a line, edge view of a surface, and true-size view of a surface. 7. Show the true size of the angle between two planes (dihedral angle). 8. Apply revolution to show true-length edges and true-size surfaces. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 2
UNDERSTANDING AUXILIARY VIEWS Auxiliary views are useful for both design and documentation. Many objects are shaped so that their principal faces are not parallel to the standard planes of projection. To show the true circular shapes, use a direction of sight perpendicular to the plane of the curve, to produce an Auxiliary View. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 3
The Auxiliary Plane To show the inclined surface (P) true size, the direction of sight must be perpendicular to the inclined plane. The auxiliary plane in this case is perpendicular to the frontal plane of projection and hinged to it. It is angled to the horizontal (top) and profile (side) viewing planes. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 4
Depth Auxiliary Views All these views show the object s depth and therefore are all depth auxiliary views. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 5
Height Auxiliary Views The front view and all these auxiliary views show the height of the object. Therefore, all these auxiliary views are height auxiliary views. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 6
Width Auxiliary Views The front view and all these auxiliary views are width auxiliary views. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 7
Secondary Auxiliary Views A secondary auxiliary view is projected from a primary auxiliary view onto a plane that is inclined to all three principal projection planes. Second Auxiliary View, showing the True Size of the Top Oblique Surface Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 8
Reference Planes Instead of using one of the planes of projection, you can use a reference plane parallel to the plane of projection that touches or cuts through the object. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 9
USING GRID PAPER TO SKETCH AUXILIARY VIEWS You can use grid paper to help sketch auxiliary views by orienting the lines of the grid paper underneath your vellum or other semitransparent drawing sheet so that the grid is parallel to the inclined edge in the drawing Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 10
HIDDEN LINES IN AUXILIARY VIEWS Generally, hidden lines should be omitted in auxiliary views, unless they are needed to clearly communicate the drawing s intent. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 11
REVERSE CONSTRUCTION To complete the regular views, it is often necessary to first construct an auxiliary view where critical dimensions will be shown true size. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 12
PARTIAL AUXILIARY VIEWS Using an auxiliary view often makes it possible to omit one or more regular views, but auxiliary drawings are time consuming to create and may even be confusing because of the clutter of lines. Partial views are often sufficient and easier to read. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 13
AUXILIARY SECTIONS An auxiliary section is simply an auxiliary view in section. Note the cutting-plane line and the terminating arrows that indicate the direction of sight for the auxiliary section. In an auxiliary section drawing, the entire portion of the object behind the cutting plane may be shown, or the cut surface alone may be shown. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 14
VIEWING-PLANE LINES AND ARROWS When the drawing sheet is too crowded to show the auxiliary view in direction projection you can use a viewing-plane line or a viewing direction arrow to indicate the direction of sight for the auxiliary view. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 15
TRUE LENGTH OF A LINE To show a line true length, make the fold line parallel to the line you want to show true length in the auxiliary view. Whenever a line is parallel to the fold line between two views, it will be true length in the adjacent view. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 16
POINT VIEW OF A LINE To show the point view of a line, choose the direction of sight parallel to the line where it is true length. 1. Choose the direction of sight to be parallel to line 1 2. 2. Draw folding line H/F between the top and front views, as shown. 3. Draw folding line F/1 perpendicular to line 1 2 where it is true length, and any convenient distance from line 1 2 (front view). 4. Draw projection lines from points 1 and 2 to begin creating the auxiliary view. 5. Transfer points 1 and 2 to the auxiliary view at the same distance from the folding line as they are in the top view and along their respective projection lines. They will line up exactly with each other to form a point view of the line. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 17
DIHEDRAL ANGLES The angle between two planes is called a dihedral angle. Auxiliary views often need to be drawn to show dihedral angles true size, mainly for dimensioning purposes. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 18
AXIS OF REVOLUTION Revolution, like auxiliary view projection, is a method of determining the true length and true size of inclined and oblique lines and planes. The axis of revolution appears as a point in this view. The object revolves but does not change shape in this view. In the adjacent views in which the axis of revolution, if it were drawn, would show as a line in true length, the dimensions of the object that are parallel to the axis of revolution do not change. Giesecke, Hill, Spencer, Dygdon, Novak, Lockhart, Goodman 19