A scale is a ruler that is used for measurement in drawing. Different scales are made for specific measurement use in engineering, mechanical drafting, architecture and metric engineering. All scales are available in a wide variety of graduations and sizes. In drawing, the word scale not only means ruler, but also a dimension that represents the structure shown in a blueprint or plan.
Engineering Scale
Engineer scales are used by engineers for measuring water mains, roads and various topographical features on drawing and blueprints. Numbers run incrementally from left to right. Each inch represents a specific amount of feet. On the scale, the small lines in between the whole numbers represent individual feet. The amount of inches to feet is written in the form of 1 inch equals 10 feet or 1:10. Scales are available in a variety of graduations from 1:10 all the way to 1:600.
Architect Scale
Architect scales are used by architects to determine the actual dimensions of a distance on blueprints or scaled drawings, much like engineer scales. They are most commonly in a triangular shape with each side indicating a separate scale. All together, a triangular scale contains 11 different scales ranging from 1/4-inch-equals-1-foot scale to 1/128-inch-equals-1-foot scale. Each scale, except the 1/16 scale, are actually two scales because it can be read from left to right or from right to left. When reading from left to right, the numbers will be located closer to the outside edge. When reading form right to left, the numbers will be closer to the inside edge.
Metric Engineering Scale
Metric Engineering Scales perform the same function as do engineering scales, but rather than using measurements equal to feet, they are equal to meters. The metric system is the standard measurement throughout most of the world, so it is useful for engineers to know how to use a metric scale as well as an engineering scale that uses it. Metric scales are also based on ratios, for example 1:50.