5.147. How are cross-sections to be represented? In making and representing cross-sections, certain conditions must be observed with regard to the indication and identification of the figures concerned and how they are to be represented, as more fully explained in paragraphs 5.148 and 5.149.
5.148. Where a figure is a cross-section on another figure, the latter should indicate the position of the section and may indicate the viewing direction by arrows at each end. In addition, in order to allow each sectional figure to be quickly identified, especially where several cross-sections are made on the same figure, each end of the cross-section line should be marked on the diagram with the same single Arabic or Roman numeral which identifies the figure in which the section is illustrated. A cross-section represents that part of an object which is situated on a cutting surface. In industrial drawings, the cross-section is that part of the object which is behind the cutting surface from the point of view of the person looking at it. Cutting surfaces are generally plane surfaces and if they are not, they must be defined precisely. Cross-sections must always follow the cutting surface, whatever it may be.
5.149. A cross-section must be set out and drawn in the same manner as a normal view whose parts in cross-section are hatched with regularly spaced parallel oblique strokes, the space between strokes being chosen on the basis of the total area to be hatched. Hatching should not impede the clear reading of the reference signs and reference lines. Consequently, if it is not possible to place reference signs outside the hatched area, the hatching may be broken off wherever reference signs are inserted. Certain types of hatching may be given a specific meaning. The hatching should be at a substantial angle to the surrounding axes or principal lines, preferably 45º. The various parts of a cross-section of the same item should be hatched in the same manner. The hatching of juxtaposed different elements should be angled in a different way. In the case of large areas, hatching can be confined to an edging drawn around the inside of the outline of the area to be hatched.
Date retrieved: 24 November 2017