Description
A straight rule with a scale engraved along the length is the simplest instrument for making linear measurements, and has been used since antiquity. However, scale rules were not commonly used for making scale drawings until around 1550 in Northern Europe. Anthropomorphic dimensions such as the foot were commonly used for the scale.

Scale rules can be straight or folding and often have even scales on one side and diagonal scales on the other, which enable the user to divide any measurement into 100 parts. They were often decorated by the maker, demonstrating artistic as well as mathematical skills (although they became more purely functional from mid 18th century). They were usually made of brass, silver, ivory or boxwood.