Frequently Asked Questions

What is tribology?
    A branch of study that deals with the design, friction, wear, and lubrication of interacting surfaces in relative motion (as in bearings or gears).

What is a four-ball test?
    A four-ball friction and wear test is used to measure the friction-and-wear characteristics of a fluid or semi-fluid material. Three 1/2-inch balls (of steel or other material) are rigidly clamped into a cup and covered with the test fluid. A fourth ball, in a chuck on top of the three bottom balls, makes point contact with each of the other three. During the test, a load (usually 40kg, 392N) is applied and the top ball is rotated at 600 or 1200 rpm. Using a load cell, we can measure the frictional force, from which we get the coefficient of friction values.