Abstract: A replaceable edge bit structure for a blade- or bucket type earthworking implement includes a bit having a pair of underbeveled catch regions in one of its faces. One of the regions has a configuration complementing that of the working edge of the implement's moldboard; the other region has a configuration complementing portions of mounting parts for the bit which are secured to the moldboard. The bit is removably held in conjoint engagement with the moldboard and mounting parts by a single pin disposed in front of and parallel to the moldboard, engaging the bit and mounting parts.