(1) The right square is generally used to inspect precision measuring tools; Level 1 is used to inspect precision workpieces; Level 2 is used to inspect general workpieces.
(2) Before use, check whether the working surfaces and edges are bruised. The left and right sides of the long side of the square ruler and the upper and lower sides of the short side are the workpiece surfaces ( right angles inside and outside). Clean the working surface of the square tools and the working surface to be inspected.
(3) When using, place the square tools against the working surface of the workpiece to be tested, and use the optical gap method to identify whether the angle of the workpiece is correct. Pay attention to handle, lean, and put lightly to prevent warping.
(4) In order to obtain accurate measurement results, the square tools can be turned 180 degrees and measured again, and the arithmetic average of the second readings can be taken as the measurement result, which can eliminate the deviation of the square itself.