Online standard ruler picture

Ruler, also known as ruler, is a tool for drawing line segments (especially straight line segments) and measuring length. There are usually scales on the ruler to measure the length. Some rulers have holes with special shapes in the middle, such as letters or circles, which are convenient for users to draw pictures. They are usually used to measure length. Generally divided into tape measure, vernier caliper, ruler and ruler.

One of Lu Ban's inventions is to draw a right triangle correctly, also called a class ruler, which can tell craftsmen which sizes are irregular and which ones are unlucky according to the rules of divination (geomantic omen). These rulers were bought today. Silk cloth ruler, also known as tailor ruler or cutting ruler, originated from the ruler with class ruler, but it has not been passed down from generation to generation, and has long lost its standard and become another ruler system.

Extended data

Rulers should be used correctly, for example, it is best not to use plastic rulers when calibrating materials, which will easily scratch. There are also many people who will make a mistake, that is, they will draw lines quickly, and then they will draw along the ruler because of its slippery characteristics, which will blur the graphics, so the speed is moderate.

It is best not to put a ruler with a knife or metal stationery, but to put a pen cover on it when it is mixed with a pen. Be sure to prevent exposure and long-term sun exposure, especially the plastic ruler has poor temperature resistance. If it will deform, it is best not to wash it with a brush, that is to say, try not to dirty the ruler.