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Understanding Lubricant Testing Method


  • Load of machine. Anti-wear (AW) Agent.
  • Additive that is active in preventing damage caused by occurrence of solid phase welding between sliding surfaces without local surface melting.
  • Purpose is to prevent abrasion and metal to metal contact.


Extreme Pressure (EP)

  • Chemical compound imparting extreme pressure characteristics to a lubricant with the objective of reducing wear under conditions where rubbing or sliding accompanies high contact pressures, as in heavily loaded gears.


Water Resistance

  • The resistance of a lubricating grease to adverse effects due to the addition of water to the lubricant system.
  • Water resistance is described in terms of resistance to washout due to submersion.


Oxidation Stability

  • Ability of a lubricant to resist oxidation and deterioration resulting from high temperatures and / or exposure to air.
  • Purpose is to prolong the life of a grease.


Timken Ok Load

  • Maximum load a lubricant will withstand without failure due to breakdown of the lubricant film, as determined on the Timken EP Lubricant Tester. In other words measure of the extreme pressure properties of a lubricant. Timken OK load is the heaviest load that can be carried without scoring.



  • One Centistoke = 1 mm/sec. 
  • When quoting a viscosity it must be accompanied by the temperature at which it was determined.
  • Viscosity Index provides a measure of how much an oil changes viscosity as temperature changes.

This is usually calculated by comparing the viscosity at 100 degree C and at 40 degree C. A high viscosity index means that the oil does NOT change viscosity as much as a low viscosity index oil.


Dropping Point

  • The temperature at which the first drop of liquid separates when the grease is heated under prescribed conditions.


Flash Point 

  • The lowest temperature at which it can vaporize to form an ignitable mixture in air. Measuring a flash point requires an ignition source.


Pour Point

  • Lowest temperature at which liquid petroleum product will flow when it is cooled under the conditions of the standard test method.
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