a cutter head assembly for a planing apparatus comprises a rotatable cutter head body , at least a first slot and a gib assembly positionable in the first slot to retain a planing knife blade . the cutter head body has a first end , an opposite second end and an outer periphery extending between the first and second ends in a longitudinal direction . the first slot is formed in the outer periphery and extends generally longitudinally . a section of the first slot has at least one profiled side and an opposite knife blade side . the gib assembly is positionable to retain a knife blade in the first slot adjacent the knife blade side . the gib assembly comprises an elongate gib having a section with a shaped leading side and an opposite trailing side . a gib screw is rotatable to move the gib toward the knife blade and clamp it .