Grease is very critical when using bearings. If deteriorated grease is used, it will definitely cause damage to the bearings. Therefore, the grease must be inspected regularly, and the inspection methods are as follows:

Hand twisting method

Twist the lubricating oil between your thumb and index finger and grind it repeatedly. The better lubricating oil will feel lubricating, less wear debris, and no friction. If you feel a large friction feeling such as sand between the fingers, it means that the lubricating oil is lubricating. There are many impurities inside and cannot be used again. New lubricating oil should be replaced.

oil drop trace method

Take a piece of clean white filter paper and put a few drops of oil on the filter paper. After the lubricating oil leaks, if there is black powder on the surface and a sticky feeling when touched by hand, it means that there are many impurities in the lubricating oil. The lubricating oil has no powder, feels dry and smooth to the touch, and has yellow marks.

oil flow observation method

Take two measuring cups, one of which contains the lubricating oil to be checked, and place the other empty on the table. Lift the measuring cup filled with lubricating oil 30-40 cm away from the table and tilt it to let the lubricating oil slowly flow into the empty cup. During the operation, observe the flow situation. Good-quality lubricating oil should flow in a slender, even, and continuous manner. If the oil flow is fast and slow, and sometimes large chunks flow down, it means that the lubricating oil has deteriorated.

Illumination method

On a nice day, use a screwdriver to lift up the lubricant at a 45-degree angle to the horizontal. Observe the oil droplets against the sunlight. Under the light, you can clearly see that there is no wear debris in the lubricating oil, which means it is good and can continue to function. If there are too many wear debris, the lubricating oil should be replaced.

Regularly checking the grease of the bearings through the above methods can ensure the normal operation of the bearings.