ASTM D5183 Determination of the Coefficient of Friction of Lubricants
ASTM D5183 Standard Test Method for Determination of the Coefficient of Friction of Lubricants Using the Four-Ball Wear Test Machine
8. Preparation of Apparatus
8.1 Set up the drive of the machine to obtain a spindle speed of 600 +/- 30 rpm.
8.2 Set temperature regulator to produce a test-oil temperature of 75 +/- 2°C (167 +/- 4°F).
8.3 If an automatic timer is used to terminate a test, it should be checked for the required +/-1 min accuracy at 60 min elapsed time, and +/-10 s at 10 min elapsed time.
8.4 The loading mechanism should be balanced to a zero reading with all parts and test oil in place. To demonstrate proper precision an addition or subtraction of 2.0 N (0.2 kgf) should be detectable in imbalance. Determination of accuracy of loading at 147 and 392 N (15 and 40 kgf) is difficult and generally limited to careful measurement of lever-arm ratios and weights or piston diameter and pressure gage calibration.
NOTE 2 - Because of differences in the construction of the various machines on which the four-ball can be made, the manufacturer's instructions should be consulted for proper machine set up and operation. FIG. 1 Schematic of a Four-Ball Wear Test Machine
9. Conditioning
9.1 Test Conditions - See Table 1.
