A hardness tester is a precision instrument that requires regular cleaning. How often do you clean the hardness tester, depending on its working environment and cleanliness. The following describes the maintenance of the hardness tester. 1. For non-metallic surfaces, wipe with a soft cloth dampened with a mild liquid detergent. Do not use too much detergent because it can penetrate into the inside of the machine and cause damage to the parts. 2. For metal surfaces, use a soft cloth dampened with light motor oil to wipe clean. Do not use too much oil. Excessive oil is easy to absorb dirt and other debris. Clean the mating surface between the lifting screw and the test bench, the shoulder of the indenter and the surface of the spindle rod. Contaminants, oil, metal chips and other debris between these surfaces can compress during the test and cause inaccurate test results. Keep the lifting screw clean, and the screw at the lower end of the lifting screw protection cover and the top of the rotating wheel is free from dust and dirt. Lubricate the lifting screw You should regularly lubricate the lifting screw with oil to prevent the lifting screw from blocking. Before the lubrication rod, check the following: * No test piece, test bench or indenter is installed on the hardness tester. * The lifting screws are all extended. Procedure (a) Remove the protective cover as shown in Figure 7-2. Figure 7-2 Removing the protective sleeve (b) Check the dirt, fibers or other debris of the screw threads. If anything is found, use a cloth to remove them. (c) Add some oil to each thread in a controlled manner, and do not add too much. (d) Use a cloth to wipe off any excess oil. Note: Small fibers or other debris can block the lifting screw. After lubricating the screw, remove all traces of cotton wool with a soft brush. (e) Use a soft brush to remove lint or fiber. (f) Replace the shield. (g) Lift the screw several times to make the oil evenly distributed.