Lubricants are the lifeblood of engine and machinery. The purpose of lubrication is to prevent contact between the rolling elements or between the shaft and bearing. Lubricants are necessary, and are composed of the proper additives with defined viscosity. The correct lubricants to be used are determined by the speed and load carried.

For oils, viscosity is the prime determination in the selection of lubricants. High or low temperature and speed determine the required viscosity. Lubricants form a thin film between the races and the rolling elements. Insufficient viscosity will allow the two surfaces to make contact, generating heat, wear and surface degradation.

Importance of proper grease and oil
Engineers typically use grease to lubricate bearings because it is easy to handle and offers protective sealing capabilities for the system. Another lubrication option is oil, which flows freely and carries away heat, making it suitable for high speed or high temperature operations.

When applied properly, lubricants can:

• Reduce the friction and abrasions caused by direct metal-to-metal contact;
• Transport heat generated by friction;
• Prolong overall engine and machinery service life;
• Prevent harmful rust and corrosion;
• Prevent foreign objects and contamination from interfering with the rolling elements.

• Selecting the wrong lubricant type - Grease and oil each have their own purpose, depending on the specific application;
• Using too much or too little grease/oil - Too much grease can cause bearing temperature to rise, especially when operating at high speeds, while too little grease results in damage due to metal-to-metal contact;
• Mixing grease and oil - Each type of lubricant provides different benefits, but they should always be used separately;

Contaminating the grease/oil with objects or water - The lubricant's primary function should be to seal the contact surface and prevent the entrance of media or water.