Support member

A metal support member which supports a rotary member directly or through a bearing and which has a plurality of projections at its outer circumferential surface, wherein said plurality of the projections are formed at the outer circumferential surface as a whole at the time of casting of the support member and said support member is formed by a pair of split members with semicircular cross-sections, and wherein at least part of the projections have a first part that is distal to the outer circumferential surface and a second part that is proximal to the outer circumferential surface, the first part having a first thickness and the second part having a second thickness, the second thickness less than the first thickness, and wherein at least part of the projections are substantially spherical projections connected to the outer circumferential surface, the spherical projections randomly positioned on the outer circumferential surface.