How To Detect Your Own Level Is Not True Level
A horizontal ruler is a common tool used to detect whether a flat surface is horizontal or not. It is simple, practical and easy to carry.
Commonly used horizontal ruler is a long strip shape, the middle of the ruler has a small horizontal water column, there is a small bubble inside the water column. Adjust the two ends of the plane parallel to the plane so that small bubbles in the middle position, the plane is in a horizontal state.
Horizontal ruler surface should be kept flat and smooth, can not have bending deformation, you can use the ruler close to both sides of the horizontal ruler to check whether the straight; level of detection is generally 180 degrees with the reversal method of verification: the level of flat On a flat surface, adjust the plane so that the bubble in the horizontal ruler is in the middle, then the horizontal ruler rotates 180 degrees to swap the positions of both ends to see if the bubble is still centered. If you swap the bubble after both ends of the bubble is no error in the horizontal ruler, if the bubble is biased to the side of the horizontal deviation, you need to correct. This method does not need other tools, simple and practical. You can also borrow other high-precision level correction, such as infrared level contrast correction.