TM 9-2920-243-34 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 a fine  mill  file. (2)  If  bushing-type  bearing  did  not  meet allowable  wear  limits,  remove  old  bearing  as shown in figure 3-31. Install a new bearing in the same manner. It should be pressed in so that it is flush with housing bore. Drill bushing oil hole using a 21/64-inch diameter drill and oil wick bore as a pilot. Ream bearing to a diameter of 0.730± 0.001-inch. NOTE Bearing can be pressed flush more easily if a 15/16-inch arbor is used. This will not allow  bearing  to  be  pressed  below  surface. Figure 3-31. Removing or installing bearing in commutator end housing. e.  Armature. (1) Resurfacing. Sharpen lathe cutting tool to dimensions given in figure 3-32. For commutator turning,  lathe  cutting  tool  must  be  extremely sharp. After grinding, hone tool with a fine hard stone  to  insure  a  smooth  cut  during  turning operation. Position  tool  with  respect  to  commutator  as shown in figure 3-33. Resurface commutator at 800 rpm taking only light cuts each time. No more than 0.005-inch should be removed during any one  cut  and  the  final  cut  should  not  be  more  than 0.002-inch.  After  resurfacing,  check  commutator against  limits  specified  in  repair  and  rebuild standards  (para  3-31)  and  replace  it  if  it  falls below  these  limits. NOTE When a cut is started, it should be carried across entire surface without stopping. 3-13