12" Triangular Engineer's Scale, Professional-Grade-Ruler, Aluminum, Color-Coded Grooves

12" Triangular Engineer's Scale: The engineer's scale, also known as a civil scale, is used for measuring length and transferring length measurements at different scales or proportions of actual length. It is triangular in cross-section with each of the three faces containing two different scale markings for a total of six scales. In North America, the scales are labeled 10, 20, 30, 40, 50 and 60, with the graduations representing decimal fractions of an inch. Thus, one inch on a drawing equals between 10 to 60 feet. The engineer's scale is slightly over 12 inches in length, but with only 12 inches of markings, leaving the ends unmarked. The extra length accounts for wear and tear over time and prevents the end ticks from wearing off. Although similar in appearance to an architect's scale, the engineering scale is designed to be more precise and has a decimal scaling scheme whereas an architect's scale uses fractional scaling. It is designed to only be read from left to right. An architect's scale can be read from either the left or right side.