1.1 This test method covers a procedure for determining the coefficient of friction by means of the Four-Ball Wear Test Machine.

1.2 The values stated in either SI units or in the former cm-kgf metric units are to be regarded separately as the standard. Within the text the cm-kgf units are shown in parentheses. The values stated in each system are not exact equivalents, therefore each system must be used independently of the other. Combining values from the two systems can result in nonconformance to specification.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given in Notes 2, 3, 4, 5.