Basic Concept of Scale
A scale ruler is a tool for measuring distances and transferring measurements at a fixed ratio of length; two common examples are an architect's scale and engineer's scale.
Types of Scales in engineering drawing - Plain Scale, Diagonal Scales, Comparative Scale,
Vernier Scale and Scale of Chords.
A scale is defined as the ratio of the linear dimensions of the object as represented in a drawing to the actual dimensions of the same. The proportion by which the drawing of a given object is enlarged or reduced is called scale of the drawing. Object is drawn on sheet to its actual size, then its drawn at full scale.