The single direction thrust ball bearings can only be used to carry axial load in one direction. Single direction thrust ball bearings have planar housing washer and an aligning seat washer. Generally, planar housing washer will not allow any angular error, however, when designing bracing structures, a gap of 0.5-1mm between the outer diameter of housing washer and the fitting surface of bearing block can be kept to correct the angular errors, which, would be made when mounting. Please note aligning housing washer needs to be ordered additionally.