How to pre tighten precision spindle bearings

The spindle bearings that require pre tightening are generally angular contact ball bearings used as front bearings. Angular contact ball bearings are generally 

used in groups, and there are two ways to pre tighten them:

1. Add a spacer sleeve between the bearings, top the outer ring, and press the inner ring with a preload nut.

2. Top the outer ring on one side of the spindle end and press the inner ring with a preload nut at the back.

The parallel accuracy of the two ends of the spacer sleeve in Method 1 must be very good. In Method 2, the vertical accuracy of the outer ring on the axis should 

be very good.

The requirement for the vertical accuracy between the bearing side and the thread of the locking nut is also high.In addition, the bearings must not be installed 

upside down, as if installed upside down, the bearings will be compressed and dispersed.Note that the pre tightening amount (or pre tightening force) must meet 

the requirements of the bearing manual, otherwise it may also damage the bearing.