Selection of Oils.

Bearings vary in size from small to very large; they run at speeds from slow to extremely high: they operate under temperatures from below zero F. (—18 deg. C) to 300 deg. F. (150 deg. C.) and over; and pressures range from light to abnormal. In every plant and on individual machines there are many bearings, on which the method of supply varies from hand oiling to circulation systems, in other words, from the crudest method to the most refined. In different industries the same machines are subjected to different service; some subject to water contamination, others subject to the presence of dirt and impurities.

Because of the many complexities and influencing factors, it is impossible to lay down simple rules, arbitrary specifications or other rule-of thumb methods, for the selection of oils. The correctness of an oil can be judged only by the actual service that it renders under the existing conditions of practice. For this reason, broad experience is essential in order that the correct selection of the most suitable lubricant can be made.