The oil or grease used to lubricate ball and roller bearings (roller contact bearings) serves many important functions. It provides a lubricating film among the balls, rollers, and retainers and between the surfaces of the ends of the rollers and the races. The oil or grease disperses heat caused by rolling friction and prevents corrosion of highly polished parts. It also helps keep dirt, water, and other foreign matter out of the parts. You must use the lubricant recommended for each machine, and you should avoid too much lubrication. Information about greases is given in the Naval Ships Technical Manual, chapter 262.

LUBRICATING OILS

Lubricating oils approved for shipboard use are limited to those grades and types necessary to provide proper lubrication under all anticipated operating conditions.

For general lubrication and in hydraulic systems that use petroleum-based lubricants, the Navy must use certain oils. These special viscosity series of oils are strengthened with oxidation and corrosion inhibitors and antifoam additives. Deck machinery uses compounded oils, which are mineral oils with additives.

Special lubricating oils are available for a wide variety of services. The Federal Supply Catalog has a list of these oils. Among the most important specialty oils are those used for lubricating refrigerant compressors. These oils must have a very low pour point and must be maintained with a high degree of freedom from moisture.

Lubricants for reciprocating internal-combustion engines are commonly known as detergent or dispersive oils. These lubricants contain additives that keep combustion products such as fuel, soot (unburned carbon), and oxida-tion (acid-forming) products in suspension, thereby reducing the amount of contaminants deposited on engine parts. These engine oils also contain additives that reduce wear and inhibit rusting, foaming, and oxidation. These advan-tages are particularly important in modern, high-speed, turbocharged marine diesel engines. Shipboard diesels operate satisfactorily on a single viscosity grade, MIL-L-9000 (military sym-bol 9250). However, for engines that may be operated in an environment of 0C (32F) or below, MIL-L-2104 (military symbol OEHDO 10) oil is recommended. For standardization, engine oil is generally used in reduction gears associated with shipboard diesels. Although 9250 oil is not formulated as a gear oil, it performs well in such applications. For additional information on lubricating oils, refer to the Naval Ships Technical Manual, chapter 262.