4-Pt CONTACT BEARINGS:

APG recommends mounting radial and 4-Pt contact bearings containing snap-over separators with the solid portion of the separator on top of the ball to prevent possible dislodging of the separator under vibration or similar conditions.  When the bearing axis will be within 45 degrees of vertical it is strongly recommended to position the solid portion of the separator on top and the pocket opening on the bottom and consider extending a shoulder of the shaft or housing as a secondary means of retention.  All sealed bearings contain an arrow indicating that the solid portion of the separator is on top when the arrow is pointing up.

it is recommended that mounting surfaces of mating parts be manufactured with tolerances equal to or better than the bearing radial and axial runouts to prevent distortion of the bearing races which directly impact bearing torque and life.