Counterboring and Spotfacing. Counterboring and
Counterboring enlarges the end of a hole by cutting a
cylindrical surface concentric with the original hole to
allow the bolt or screwhead to be sunk below the surface.
Spotfacing cuts a smooth, flat surface which is
perpendicular to the axis of the hole. This surface usually
serves as a seat for the head of a bolt, cap screw, or nut.
counterboring and spotfacing procedures.
Lapping . Lapping is done to produce a
geometrically true surface, improve accuracy, or provide
a very close fit between contacting surfaces. Since a
very minute amount of material is removed from the
workpiece, lapping is the final operation.
Bearing Roll Staking. Slight axial movement of
installed bearings can be prevented by bearing roll
staking. This method of bearing retention consists of
deforming the bearing housing by means of a swaging
roller. Refer to the applicable maintenance manual for
bearing roll staking procedures.