Rule

A rule is a measurement device that can also be called a line gauge or a ruler. Comprised of a straight edge device marked with graduations for measurement, rules are used to take the straight measurement of a part, measure and mark increments along an object, or to measure distance. Rules can be made of many different materials including wood, plastic, or metal. Additionally, rules vary in length and width. Graduations on a rule are either scribed, painted, etched, printed, or engraved onto the tool. Depending on what material the rule is made out of, these different methods of marking graduations will have different durability. Rules can be built to be flexible or rigid. Finally, the five standard types of rule include: spring-tempered rule, flexible rule, narrow rule, hook rule, and short-length rule.