The term universal means that the bearings can be used in any arrangement, tandem, back to back or face to face. 

The preload step is manufactured on the rear face of the inner ring and the front face of the outer ring, both steps are exactly the same depth therefore the universal bearing can be used in any combination.

Back to Back (DB Arrangement)

The majority of machine tool applications use this type of arrangement. The preload is produced by the ‘Gap’ (2 x the step b) of the inner ring faces being squeezed together by a locknut on the shaft. This type of arrangement is particularly useful where moment loads are used but the accuracy of the housing must be high to reduce misalignment.

Face to Face (DF Arrangement)

This arrangement is often used for ball screw support bearing applications. The preload is produced by the ‘Gap’ (2 x the step f) of the outer ring faces being squeezed together by an end cap in the housing. This type of arrangement is particularly useful when good alignment cannot be guaranteed between the housings. This can be the case for Ball Screw Support Bearings since ball screws can often be 1 to 5 metres in length.

Tandem (DT Arrangement)

This arrangement needs to be used with another bearing or set of bearings in the opposing direction in order to produce a preload (see diagram). Bearings are used in these arrangements when there is a need for higher stiffness due to higher axial loads on the spindle.