NOTE

When sectional views are made, the part that is cut by the cutting plane is marked with diagonal parallel section lines. The process of making these lines is termed "cross hatching." Shafts, bolts, nuts, screws, keys, pins, rivets, balls, etc. , the axes of which lie in the cutting plane, have no interior parts to be shown and consequently are left in full on assembly sections, as if they had been removed when the section was cut off and afterward laid back in place.

4 . Conventional Breaks

In describing the shape of an object, such as a long bar or similar object that is small in cross section but of considerable length, the draftsman is faced with two problems: first, if drawn to full size, it would require a large sheet of paper with considerable space wasted; second, if drawn to a small scale, it would be too small for dimensioning clearly. If the object is uniform in shape, there is no necessity for drawing its entire length. A piece is "broken cut," therefore, and the object is drawn full size. The methods used to indicate this are termed "conventional breaks." Figure 86 shows some of the most common of these.

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Freehand Sketching An Introduction

Freehand Sketching An Introduction

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