How does Luban ruler measure the gate?

How to measure the door with Luban ruler:

Measure the inner diameter of the door and the left and right sides of the furniture. Based on centimeters (centimeters), refer to the words above the black line in the middle. For example, 38 centimeters means wealth is the most important, then 38 centimeters is an auspicious size and can be used with confidence.

The Luban ruler is used in combination with the curved ruler: the Luban ruler sold in the market is marked with red and black. If the required length falls on the "red" of the Luban ruler, it is auspicious. Then use a curved ruler to measure it. If the required length falls on the "white (one white, six white, eight white)" sides of the curved ruler, it is auspicious.

Extended information:

Relevant requirements for Luban ruler:

1. Luban has many inventions and creations. Many ancient books record that many woodworking tools used by carpenters were invented by him. Like the curved ruler used by carpenters, it is called Luban ruler. Another example is the ink fountain, umbrella, saw, plane, drill, etc. It is said that Lu Ban invented it.

2. The Luban ruler is about 46.08 centimeters long. According to legend, it was made by Gongshuban of the State of Lu in the Spring and Autumn Period. Later, the eight characters were added through the Feng Shui community to measure the good and bad luck of the house, and it was called the "door meter ruler". Also known as "square ruler", it is a woodworking tool mainly used to check whether the planed boards, planks and structures are vertical and the edges are at right angles.

3. 1 city ruler = 0.8 Luban ruler. Luban ruler was integrated with Dinglan ruler soon after its creation, and later with inches and centimeters. It is an important tool for measurement and correction. Due to its special functions, it is most widely expressed in Feng Shui culture and architectural culture.

Baidu Encyclopedia-Luban Ruler