Abstract: This corner joint, which serves to connect together a plurality of hollow frame members, comprises a metal trunk member containing a plurality of holes and a plurality of metal posts mounted on and projecting from the trunk member. Each post has an inner end fitting in one of the holes, an externally-threaded outer end, and a body portion between the two ends having a non-circular outer periphery. A plurality of hollow plastic sleeves respectively fit over the outer peripheries of the body portions of the posts. Each sleeve has an inner periphery of approximately the same shape and size as the outer periphery of the associated post body portion. Retaining nuts respectively mounted on the outer ends of the posts receive the externally-threaded outer ends of the posts.