Apparatus for measuring anti-wear properties of pressurized liquids

A testing device for determining the lubrication properties of hydraulic fluids under elevated pressures and temperatures comprises a pressure-tight housing defining a central cavity including a continuous passageway for the fluid, a chuck assembly located within the cavity which holds a plurality of test balls in fixed position, a rotatable support structure securing an upper ball in centrally disposed contact with the test balls, and a screw-threaded adjustment adapted to move the chuck assembly to apply pressure between the test balls and the upper ball. The present testing device is of simple and inexpensive construction and reduced size, and provides data respecting the test fluids which accurately reflects actual working conditions.