In engineering drawing, a scale is a set of levels or numbers used as a measuring or comparing parameter. It is the ratio of the linear dimension of an element of an object as represented in the original drawing to the actual linear dimension of the same element of the object itself. The scale is always placed in the title block in the lowest box below the main title of the drawing, or sometimes it can be written at a place very close to the drawing drawn object. The engineering scales are made in a variety of graduations to meet the requirements of many different kinds of engineering works. There are three types of scales in engineering drawing:
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Full Scale: When an object is drawn on the sheet to its actual size, it is said to be drawn to full scale.
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Reducing Scale: When an engineering drawing is prepared to a smaller size than the actual size of the object, it is said to be drawn to a reducing scale.
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Enlarging Scale: When an engineering drawing is prepared to a larger size than the actual size of the object, it is said to be drawn to an enlarging scale.
The engineering scale adopted for drawing should have a bearing on the degree of accuracy required of scaled measurements on prepared drawings. If a drawing is drawn to scale, it can be used to obtain information such as physical dimensions, tolerances, and materials that allow the fabrication or construction of the component or system.
