Axis Ball Bearing Catalog (PDF) - McGuire Bearing Company

Engineering Section
Angular Contact Installation
Proper Tightening
Note: Ring length tolerances can be held so that when the bearings are clamped together, slight
axial play exists. For most applications this is desirable (UA suffix). For some applications, no axial
play is desirable (UO suffix). For applications where extreme shaft rigidity is desired, ring lengths that
preload the assembly can be used.
Tighten the locknut hand-tight. In order to protect the key of the washer from shearing, the lockwasher
should not be used at this time. Make sure that the tapered O.D. portion of the locknut is
toward the bearing. This keeps any deformation of the slots away from the bearing (deformation of
the slots due to improper installation of the locknut can cause the bearing’s ring to become cocked
on the shaft). Once the locknut is hand-tight, wait about a minute for the shaft to pick up heat from
the bearing; then, using a spanner wrench and hammer, drive the locknut tight. “Tight” is defined as a
distinct feel that the inner rings of the bearing are seated together and the locknut will start to distort
if driven tighter. Wait about 10 minutes and re-tighten a second time. While the bearings are cooling,
use clean lint-free rags, or oil paper, to cover and protect the bearings from foreign matter contamination.
Note: Use of steel or brass drifts can cause metal flakes to be dislodged and enter the bearing. Steel
or brass drifts may also lead to further deformation of the slots, which can lead to a cocked/tilted
rings. Use of a proper spanner wrench is strongly recommended.
To check installation, after bearings and shaft are cooled, remove the locknut. Spin the outer rings
of the bearing. Try to rotate one outer ring CW while trying to rotate the other outer ring CCW. This
should be difficult with a normal clearance (UA suffix) designation and not possible with a preloaded
bearing. Depending on the preload, the bearings should now turn, in the same direction, freely, or
with slight resistance. The resistance to turning the bearing should be consistent through 360 degrees
of rotation. Inconsistent resistance to rotation is an indication of an incorrectly mounted bearing,
or a sign of foreign material in the bearing. If you can not get the bearings to spin with consistent
resistance, remove the bearings to investigate. Do not proceed!
If a bearing must be removed from the shaft, it is generally best to replace it. Whenever a bearing
is removed from the shaft, there is a risk of damage to the rolling elements and rings. The cost of a
new bearing is a fraction of the cost of a pump or motor that goes out of service prematurely. If the
installed bearings spin properly, install a new locknut and lock-washer and tighten. Then bend a tang
on the lockwasher into one of the notches on the OD of the locknut.
With cleanliness in mind, hand pack the bearings with appropriate grease if it is grease lubricated
(20-30% fill is typically recommended). If it is oil lubricated, oil the bearing down with the correct
clean oil. Install the housings, covers, seals and slingers to complete rotating element assembly and
protect the bearing.
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