A standard block is an easy way to check the accuracy of your hardness tester. For a simple comparison, you place a standard block on the test bench for a hardness test and compare the measured hardness value to the number engraved on the test block. This comparison indicates whether the hardness tester needs repair. Note: In the case of frequent use, you should check the accuracy of the hardness tester every day. Always pay attention to the following before you perform the standard block inspection. (a) The standard block should use the top surface. If the bottom or side surface is used, the correct hardness value will not be obtained. (b) To use a good standard block, do not use standard blocks between indentations that are at least 2.5 times the diameter of the indentation. (c) Do not use standard blocks that have worn out old dents because you are not sure if the newly machined surface has the same hardness value as the original. (d) If you use a durometer for the entire range of gauges, check the high, medium and low ranges of the scale. If you only use one or two ranges, you can select standard blocks above and below these range hardness values. (e) Precautions for the test: You should perform at least 5 tests on the working surface of the standard block (the first point is not marked), and the hardness value is marked on the side of the work surface. If the average value of the hardness of the test is compared with the calibration value engraved on the working face of the standard block, and the error generated is within the allowable range, it is qualified. If the average of five readings is outside the limits of the Rockwell hardness standard block: □ Check the indenter, replace the ball in the ball indenter, or check the tip of the diamond cone indenter with at least 10 times the magnifying glass, if any Obvious damage, replace the diamond cone indenter. □ Check the fit between the indenter and the spindle shaft. The surface is clean and free of dirt, debris and oil. These things prevent the pressure head from being properly placed and cause the test results to fail. When you replace the indenter or test bench, several adaptation tests should be performed to secure the components.