ASTM D4170 test method for fretting wear protection by lubricating greases
9. Procedure
9.1 In a dust-free environment, install the test grease in unused, cleaned, weighed bearings.

9.1.1 Fill the ball tracks of the bearing races with the test grease. Use a suitable spatula to strike the grease level with the bearing lands. Bearing backs and bearing seats must be kept free of grease and particulate matter. Clean with a lint-free cloth slightly moistened with n-heptane.

9.1.2 Fill each ball retainer with test grease taking care to fill all the cavities around the balls on both sides of the retainer. Remove excess grease from the bore and rim of the retainer, but leave an excess of grease on the cupped side. Adjust the mass of the grease in each bearing to 1.0 +/- 0.05 g.

9.2 Assemble the chuck. Use Fig. 5 as a guide to chuck assembly. Use minimal force when tightening set screws. Locate bearing set screw flats normal to set screws. Purpose of set screws is to prevent rotation of races in seats. To preclude overtightening set screws, grasp hex-key (Allen wrench) by shank rather than by lever arm. If set screws tend to loosen during the test, use a low-strength anaerobic sealant (MIL-S-22473D, Grade H or similar) on the threads rather than more force. Bearing races must bottom on bearing seats. Bottoming can be verified by visual and tactile inspection. (Warning - Tight set screws, misalignment between set screws and flats, or set screw flats that are not square with the bearing face can cock the bearing upon tightening set screws, causing uneven wear. Loose set screws combined with oily or greasy bearing backs and seats could allow a poor grease to give erroneous test results because of race creep effects.)

9.2.1 Install an upper bearing race in the chuck top and tighten the set screw, using minimal force.

9.2.2 Invert the chuck top and secure in a bench vise.

9.2.3 Place the retainer of the upper bearing on the race in the chuck top (9.2). The cupped side must be positioned upward during assembly (downward during operation).

9.2.4 Install the other race of the upper bearing in the oscillating bearing seat. Using minimal force, tighten the set screw. (With all bearing set screws oriented alike, permanently mark the underside of the oscillating bearing seat crank arm. Thereafter, when using the same orientation for assembly the lower bearing race will always be installed in the same seat.)

9.2.5 Install a lower bearing race in the oscillating bearing seat. Using minimal force tighten the set screw.

9.2.6 Assemble the oscillating bearing seat on the shaft such that the upper bearing components are properly mated.

9.2.7 Place the lower bearing retainer on the race in the oscillating bearing seat. Position the cupped side upward.

9.2.8 Install the other lower bearing race in the chuck base. Using minimal force tighten the set screw.

9.2.9 Place the chuck base on the shaft.

9.2.10 Assemble the spring guide, spring, load shim (if required), spacer, washer, and lock nut on the shaft. While holding the chuck base and oscillating bearing seat to prevent rotation, tighten the lock nut until the spacer bottoms on the shaft shoulder.

NOTE 4 - Spring alignment may affect wear pattern. To ensure consistent spring alignment, paint a reference mark on the (cleaned) spring and thereafter, always install spring with mark aligned with the set screw in the chuck base.

9.2.11 Remove chuck assembly from vise. Loosen all bearing race set screws. While holding chuck base in one hand, strike head of shaft with a 0.5-kg (1-lb) (approximate) soft-faced hammer to assist bearing seating. Lightly tighten all set screws.

9.2.12 Apply a film of grease to the surfaces of the chuck that contact the housing.

NOTE 5 - Use any low-fretting wear grease.

9.2.13 Place the chuck in the housing with the chuck firmly seated against the housing shoulder. Tighten the set screw in the side of the housing.

NOTE 6 - Some chuck bases (Fig. 5) have been supplied without a set screw flat. If the chuck base does not have a flat, grind flat, approximate dimensions, 9.5 by 9.5 by 0.5 mm (3/8 by 3/8by 0.02 in.), corresponding to set screw in housing (Fig. 2, left side).

9.2.14 Attach the connecting rod to the arm of the oscillating bearing seat. Apply a drop of lubricating oil to each connecting-rod end bearing (Note 5). Install the connecting-arm guard.

NOTE 7 - With prolonged usage, certain tester parts may wear or deteriorate. Check rod end bearings for wear prior to each test. Replace with new bearings at the first sign of looseness. Frequent lubrication (automatic transmission fluid is suitable) will prolong bearing life. Check Quad-ring or O-ring in chuck top for swelling or other deterioration. If necessary, replace with new Quad-ring.

9.3 Place tester on vibration mount.

NOTE 8 - Tester may be placed on full sheet of vibration pad (or equivalent) but more economical use of pad and better vibration control can be achieved by placing suitability sized (approximately 75 by 75 mm) sections under each tester foot. Vibration control will be improved if grain of pads is alternated.

9.4 Run the test for 22 +/- 0.1 h by setting the time switch and the ON-OFF switch. The test will terminate automatically.

9.5 At the end of the test, disassemble the machine and remove all bearing components from the chuck.

9.6 Remove the bulk of the grease from the bearings with a clean, soft cloth.

9.7 Clean the bearings as outlined in 8.3, except use 1,1,1-trichloroethane (see 7.3).

9.8 Weigh the bearings as outlined in 8.4.

9.9 Calculate mass losses of upper race pair and lower race pair. Do not include mass loss of balls and retainers. Calculate the mean of the upper and lower mass losses.

9.10 Calculate the mass loss ratio by dividing the mass loss of the upper race pair by that of the lower race pair. (See 11.1.3.)