What should I do if the ruler is broken and I can't see the zero scale?

If the scale is broken and the zero scale cannot be seen, measure the whole scale line behind the zero scale as the zero scale line, and then subtract the whole scale value from the measurement result.

Ruler, also called measuring ruler, is a tool for drawing line segments (especially straight line segments) and measuring length. There are scales on rulers, and some rulers have special holes in the middle, such as letters or circles, which are convenient for users to draw. It is usually made of plastic, iron, stainless steel and plexiglass, and is generally divided into tape measure, vernier caliper and ruler.

Development history

One of Lu Ban's inventions is that he can correctly draw a right triangle, also called a class ruler, and 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.

Production and production

Rulers used in different occasions have different requirements and standards. If the numerical value is required to be more accurate, then higher technology is needed and it must be produced by machine. The second point is the quality of engraving, which is usually branded with protective film after engraving. The third point is the choice of materials. Now it is divided into plastic, metal and wooden rulers. Plastic rulers are mainly used by ordinary students in stationery, metal rulers are more used in industry, while wooden rulers.