TM 9-2920-243-34

TM 9-2920-243-34Figure 3-31. Removing or installing bearing in commutatorend housing.Figure 3-30. Removing or installing bearing in shift housing.d. Commutator End Housing Assembly.(1) Smooth minor damage such as nicks,burs, etc., on mating surface of housing with afine mill file.(2) If bushing-type bearing did not meetallowable wear limits, remove old bearing asshown in figure 3-31. Install a new bearing in thesame manner. It should be pressed in so that it isflush with housing bore. Drill bushing oil holeusing a 21/64-inch diameter drill and oil wick boreas a pilot. Ream bearing to a diameter of 0.730±0.001-inch.NOTEBearing can be pressed flush more easilyif a 15/16-inch arbor is used. This will notallow bearing to be pressed below surface.e. Armature.(1) Resurfacing. Sharpen lathe cutting tool todimensions given in figure 3-32. For commutatorturning, lathe cutting tool must be extremelysharp. After grinding, hone tool with a fine hardstone to insure a smooth cut during turningoperation.Position tool with respect to commutator asshown in figure 3-33. Resurface commutator at800 rpm taking only light cuts each time. No morethan 0.005-inch should be removed during anyone cut and the final cut should not be more than0.002-inch. After resurfacing, check commutatoragainst limits specified in repair and rebuildstandards (para 3-31) and replace it if it fallsbelow these limits.NOTEWhen a cut is started, it should be carriedacross entire surface without stopping.3-13