Abstract: An assembly for testing the rolling contact fatigue of a test element for evaluating the differences in the fatigue life between like materials manufactured by different manufacturers or the fatigue life of different bearing materials, heat treatments, surface coatings, lubricants, operating variables, etc. The assembly is configured to rotate load balls around a track in contact with a stationary test element. By allowing the test element to remain stationary during the test, sensors can be installed directly onto or into the element. It is possible to configure the present assembly so that sensors may be placed within millimeters of the rolling contact test track effectively eliminating outside noise and error signals and increasing the accuracy of the sensor measurements. The stationary mounting of the test element also facilitates control of the temperature of the element.

Abstract: Iron and steel interference fit assemblies with increased retention forces comprised of a purposely formed iron oxide layer of limited thickness on one or both of the mutually engaging surfaces. The new methods to create the new interference fit assemblies comprise heating of iron and steel parts intended for press fit assembly to temperatures substantially between 500.degree. F. (260.degree. C.) and 1050.degree. F. (566.degree. C.) for periods of time in air between ten hours and ten minutes to create an iron oxide surface layer of optimum thickness on at least one of the mutually engaging surfaces prior to assembly. Other methods to generate the optimum thickness of iron oxide layer may also be used. The iron oxide surface layer substantially increases the frictional retention force in the assembly. The retention force effectively doubles with heating at 700.degree. F. (371.degree. C.) to 800.degree. F. (427.degree. C.