four-ball tester

four-ball tester

[¦fȯr ¦bȯl ′tes·tər]
(engineering)
A machine designed to measure the efficiency of lubricants by driving one ball against three stationary balls clamped together in a cup filled with the lubricant; performance is evaluated by measuring wear-scar diameters on the stationary balls.
References in periodicals archive ?
The test oils are tested for improvement in tribological properties on a four-ball tester. The weight percentage of surface-modified and ball-milled MWCNTs is maintained as 0.5 wt %.
In this test on four-ball tester a series of 10 tests of 10-second duration are carried with varying load under the following conditions: