ASTM D4170 test method for fretting wear protection by lubricating greases
8. Bearing Preparation
8.1 Grind a suitable set screw flat (approximate dimensions; 8 by 4 by 0.5 mm) on the periphery of each bearing race; flat must be square with face to prevent cocking of races when set screws are tightened.
NOTE 3 - It is extremely difficult to grind the flat square with the face when using a hand or bench grinder. Good results have been obtained by racking a number of bearing races in a V-block and using a surface grinder.
8.2 Scribe suitable identification marks on the outer lands of bearing races to distinguish races of upper bearing from races of lower bearing. Identification marks should not be scribed on back or periphery of the bearing race.
8.3 Fill tank of ultrasonic cleaner with distilled water to a depth of 30 to 40 mm. Place two bearing sets in a 250-mL beaker containing about 125-mL of n-heptane. Cover beaker and place in ultrasonic bath. After cleaning for 10 to 15 min, transfer bearing parts to second beaker containing 125 mL of n-heptane (see 7.2). Clean for 8 to 10 min, then repeat operation for two additional 4 to 5-min washes, using new n-heptane and clean beakers each time.
8.4 Place bearing parts onto freshly cleaned, glass Petri dishes or aluminum moisture dishes to air dry. Bearings should be propped against rim of dish to permit air circulation. Clean bearings must not be rotated or air blown. Do not place bearings on any surface other than freshly cleaned glass or metal. Do not touch bearings with bare hands; use forceps or tongs, or wear surgeon gloves or finger cots.
8.5 When bearings are dry, place dishes containing bearings in a desiccator and let stand for a minimum of 30 min.
8.6 Weigh the upper and lower bearing race pairs separately to the nearest 0.1 mg. (Each race pair consists of two races.)
