Fig. 36A illustrates a very compact way of showing sections of symmetrical parts. The left-hand half of the view shows a section along the axis of the gudgeon pin, while that right-hand half is a section at right angles. This method is much used for spare

parts lists or, as in this case, to show the relative proportions of the parts ('B' is the cylinder bore on this drawing). It is seldom used for dimensioned drawings.

In Fig. 37 we have the conventions for successive sections, where, for example, a shaft carries a number of different shapes on the diameter. The preferred method is to show the sections in true projection, as at the top of the sketch. However, this can be wasteful of space on the drawing, in which case the sections can be set below the elevation of the shaft. Again, the preferred convention is that each sectional view should have its centreline on the line of the cutting plane. However, if this is not possible e.g. due to cutting planes being too close together, the sectional views may be set at your convenience, provided that each is properly labelled.

Oblique sections (Fig. 38)

Sectional views are frequently useful in pictorial assembly drawings, of which this drawing is an example. Care must be taken sections

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