US Patent 7837535 Superfinishing stone and superfinishing process using the same

A superfinishing stone 2 is slid on a rotating subject surface 7 as pressed against the subject surface 7 and is held in contact against the subject surface 7 as vibrated thereon in a different direction from the sliding direction. The superfinishing stone includes plural stone portions 3, 4 divided by a split surface 6 inclined to both the sliding direction and the vibrating direction and mutually independently movable along the split surface 6 and in the pressing direction.