Copyright Goodheart-Willcox Co., Inc. Unit 6 Section Views 123 When possible, the section view should be arranged in orthographic projection with the other views. Scale and sheet size are two factors that are consid- ered when deciding where to place the section view. For multisheet drawings, it is highly desirable to keep the section view on the same sheet as the view that shows the cutting plane, although section names and zoning can assist in cross-referencing sections to other sheets if required. Section View Types There are several types of sections. Each is designed for a specific purpose. A full section is created when the cutting plane passes entirely through the object. For all practical purposes, the object is “cut in half.” See Figure 6‑4. Notice how much more clearly the internal details appear in the section view than in a nonsectioned right-side view, where the internal details would be shown as hidden lines. Lines visible in the section view are shown, but hidden lines usually are omitted. Even if there are hidden features behind the sectioned area, showing hidden lines reduces the clarity of the section view. For complex parts, showing a few hidden lines on a section view is permitted if it eliminates the need to draw another view. A symmetrical object is the same on both sides of the center line. The half section is created when a sym- metrical object is drawn with one-half of the view as a section and the other half as a regular view. See Figure 6‑5. In essence, the half section cuts halfway through the object. In your mind, think of this as if one-quarter of the object is removed. The cutting- plane line is shown on the adjacent view, indicating where the part has been cut and the direction from which the section is viewed. Notice there is only one arrowhead on the cutting-plane line for the half-section view. Also note the preferred method of showing the section view, with a center line dividing the sectioned half from the regular half, not a visible line. After all, the object is not actually cut. The resulting section is really a “double exposure,” with two half views as one. An offset section is drawn when the essential internal details do not appear on one flat plane Goodheart-Willcox Publisher Figure 6‑3. Cutting-plane lines and section lines are used in section view drawings. Cutting-plane line is thick and replaces vertical center line Section lines are thin and uniformly spaced Goodheart-Willcox Publisher Figure 6‑4. A full section is created when the cutting plane passes entirely through the object. The cutting-plane line can be omitted on basic, symmetrical full sections such as this one. A comparison of the views shows the advantage of a section view when internal details need to be clearly visible. Views without Section View Views with Section View Show Internal Detail More Clearly