Which type of oil should NOT be used for lubricating bearings?

The use of animal oil for lubricating bearings is generally not recommended due to its properties and performance limitations compared to other types of oils. Animal oils, such as those derived from fats and greases, can break down more easily with heat and age, leading to reduced lubrication effectiveness over time. They may also have lower resistance to oxidation and can accumulate contaminants, which can cause wear and tear on bearing surfaces. This makes them less suitable for the high-performance demands typical of bearing lubrication.

In contrast, vegetable oils can be more environmentally friendly alternatives, synthetic oils are designed for superior performance under extreme conditions and have excellent stability, while mineral oils are widely used due to their balanced properties. Each of these alternatives offers better characteristics for high-load and high-temperature scenarios found in many bearing applications.