Measuring flatness by ruler
(1) Measure the flatness of the wall surface: the side of the ruler is close to the surface to be tested, and the size of the gap is detected with a wedge-shaped feeler gauge. Three points should be detected at the position, that is, the vertical - - point, and cross 45 points left and right in its original position. - point, take the average of the three points. The correct reading of the flatness value is determined by inserting a wedge-shaped feeler gauge into the largest gap. However, if the hand is placed on one end of the test, the flatness of the other end should be measured, and 1/2 of its value should be taken as results of testing.
(2) Measuring the flatness of the ground: When testing the flatness of the ground, the method is basically the same as the method of testing the flatness of the wall. It is still necessary to test three points at each place, that is, one point in the vertical direction, and cross 45° left and right in its original position. - point, take the average of the three points. However, when there is a ribbon or a door opening, it should be tested through it.
