Abstract: The method of locking a shaft within a bearing so that they are concentrically positioned against rotational and axial relative movement, and an apparatus for practicing such method comprising a complete assembly such as a pillow block bearing which includes an axial extension on the inner race ring of the bearing of a lesser outside diameter than the outside diameter of the main body portion of such inner race ring, with slots spaced equally around the circumference of such extension cut axially inwardly from the outer edge to provide multiple segments therein. A continuous circular collar positioned over the extension includes two threadably mounted set screws spaced apart within an arc substantially 30.degree. to 60.degree. on the continuous circular collar, and in such position of the collar on the extension each set screw is over a segment and the segments are separated by an extension slot.