The rotatable joinder of two sheets is provided by a two-piece
interfitting bearing assembly with each element separately attached to
one of the sheets so that the sheets are joined but rotation is
controlled by the interfitting bearing surfaces. The interfitting parts
comprise an inner and outer race which are placed together in
superposition with aligned apertures in the sheets. The rotatable
attachment of the sheets is accomplished in a single pressing operation
in which each race is simultaneously pressed into one of the sheets with
a gap remaining between them.