SELECTING MAINTENANCE LUBRICANTS.

It must be remembered that specifications define minimum acceptable quality. As a result, competition will force a supplier to deliver the least expensive product that will barely meet the specification. Frequently, a higher quality, more expensive oil would be more economical in the long run. Lubricant purchasing specifications should be reviewed and periodically updated. When the user fails to review and update his specifications on a regular basis, this can also work to the disadvantage of some oil suppliers. For example, most oil companies are adjusting the viscosities of their products to conform to the recently adopted ASTM Viscosity System for Industrial Fluid Lubricants (Method D 2422). Assume that a customer's specification calls for an oil having a viscosity of 350-380 SSU at 100 F. Since ASTM grade S-315 permits a range of viscosities from 284-347 SSU at 100 F, and the next higher grade (S-465) has a range of 417-510 SSU at 100 F, most suppliers will not be able to provide this customer with a stock oil that will satisfy his requirements.