4-Ball EP Tester
Measures lubricant extreme pressure properties! Tests under high Hertzian contact in pure sliding or pure rolling motion to determine load carrying and anti-weld properties of a lubricant under increasing test loads. Three ½ inch diameter steel balls are clamped together and covered with the test lubricant. A fourth ball is pressed into the cavity formed by the three clamped balls for three point contact, and rotated for a set duration. Lubricants are compared using the average size of the scar diameters worn on the three lower clamped balls. Determines Load-Wear Index (LWI), Last Non-Seizure Load (LNSL) and Weld Point (WP). The Four-Ball EP Tester is also used with optional fixturing to perform KRL shear stability tests according to CEC L-45-A-99.
Available in two configurations for ASTM and IP Standard Test Method. Developed by Shell Oil Company in the 1940s.