Become familiar with the scale

• 1
  Engineer's scale compared to a ruler
  
  Notice the shape of the scale. Both an architect's scale and an engineer's scale are typically slightly longer than twelve inches. But instead of being flat with two sides, like a ruler, a scale is three sided, so that it is shaped like a long triangular solid. This gives the scale six edge faces on which you'll see graduated markings.
  
  
• 2). Look at the graduated markings on the six edge faces of the scale. Each edge has a different set of graduated markings according to a certain scale.
  
  
• 3
  A "10" on an engineer's scale represents 1:10 scale
  
  Understand the difference between an architects scale and an engineer's scale. An architects scale is usually marked with the following ratios—1:1, 1:2, 1:5, 1:100, 1:500, and 1:1250. An engineer's scale is marked with the following ratios—1:10, 1:20, 1:30, 1:40, 1:50, 1:60; on an engineer's scale the ends of each edge are marked with the last number of the ratio. For instance, the edge with the markings that represent a 1:10 scale is marked with a 10. For our lesson, we'll be using an engineer's scale.
  
  

Reproduce a drawing using an engineer's scale

• 1). Choose the scale ratio that suits your needs. For our example we'll reproduce a drawing using 1:10 scale. The finished drawing will be 1/10 the size of the original.
  
  
• 2). Choose an object or drawn figure to reproduce. For our example, we'll copy a drawing of a rectangle that measure four inches by six inches.
  
  
• 3
  Measuring the first dimension of the original drawing
  
  Use your ruler to measure a dimension of the original drawing--in this case, one side of the rectangle. The side measures six inches.
  
  
• 4
  The 1:10 edge of an engineer's scale
  
  Use the 1:10 edge of the engineer's scale. Notice the scale edge is marked “10”. Notice that each inch is divided into ten equal segments. Each segment represents one real inch in 1:10 scale.
  
  
• 5
  Drawing the first side of the 1:10 drawing of a 4" x 6" rectangle
  
  Place the engineer's scale on your graph paper. From the zero position on the scale, count off six segments to represent six inches. Draw a line along the straight edge of the scale from zero to the end of the six segments you counted.
  
  
• 6
  The 3/5" x 2/5" rectangle is a 1:10 scale drawing of the 4" x 6" drawing.
  
  Repeat this process for the other sides of the original drawing, so that the original rectangle drawing is completely reproduced in 1:10 scale. The original rectangle measured 6" by 4". Our 1:10 drawing of the rectangle measures 3/5" by 2/5", which is exactly one tenth the size of the original.