How to use a marble ruler

1. Pay attention to the consistency between the granite ruler and the workpiece temperature during use. Do not hold the angle ruler in your hand for a long time. Fully consider the physical properties of marble to avoid errors. 2. When measuring, attention should be paid to the placement of the angle ruler, and it is not allowed to tilt. The angle ruler should be placed in a plane perpendicular to the intersection line of the two sides that form a right angle, that is, vertically close to the measured workpiece, otherwise measurement differences may occur. 3. When in use, place the granite ruler on the working surface of the tested workpiece and use the optical gap method or feeler gauge to identify whether the angle of the workpiece is accurate. When inspecting the outer (inner) angle of the workpiece, the inner (outer) edge of the square ruler must be in contact with the measured workpiece. When one side of the square ruler is tightly pressed against the working surface of the workpiece, gently press it down without excessive force to avoid changing the angle.

4、为取得的测量数值，用花岗石平尺测量时可将90度角尺翻转180度再重新来一次，取两次读数的算术平均值为其测量结果。