ALF double direction angular contact thrust ball bearings are designed to locate spindle shafts axially in both directions. These bearings are intended for mounting in combination with cylindrical roller bearings in the NN 30 K or N 10 K series in the same housing bore (fig. 1). This bearing combination simplifies machining of the housing bore.

Double direction angular contact thrust ball bearings are manufactured with the same nominal bore size and outside diameter as corresponding cylindrical roller bearings. However, the outside diameter tolerance of the housing washers, combined with the housing bore diameter and geometric tolerances recommended for super-precision cylindrical roller bearings under light to normal load and rotating inner ring load (Seat tolerances for standard conditions) will result in an appropriate radial clearance in the housing bore. This clearance is sufficient to prevent radial loads from acting on the thrust bearing provided that its outer ring is not axially clamped in the housing.