Three ½ inch diameter steel balls are clamped together and covered with the test lubricant. A fourth ½ inch diameter steel ball is pressed into the cavity formed by the three clamped balls for three point contact, and rotated for a set duration. Compares lubricants using the average size of the scar diameters worn on the three lower clamped balls. Coefficient of friction can also be determined. Optional systems are available for rotational speeds up to 7,200 rpm. Only test machine proven through cooperative inter-laboratory testing to meet requirements of ASTM D2266, D4172 and D5183.

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 Standards and methods

  • ASTM D 2266 Standard Test Method for War Preventative Characteristics of Lubricating Grease (Four-Ball Method)
  • ASTM D4172 Standard Test Method for Wear Preventative Characteristics of Lubricity Fluids (Four-Ball Method)
  • ASTM D5183 Standard Test Method for Determination of the Coefficient of Friction of Lubricants using the Four-Ball Wear Test Machine
  • DIN 51350 part 1-5
  • IP 300: Rolling Contact Fatigue Test for Fluids in a Modified Four-Ball Machine
  • Proposed method Ball-on-three-disks (for low viscosity fluids, or to change the metallurgy)