A blade assembly comprises a moldboard defining an upper moldboard free end and a lower moldboard free end, the lower moldboard free end defining a lower curved mounting surface, and an adapter board defining an upper adapter board attachment portion, and a lower tool bit attachment portion. The upper adapter board attachment portion may include a first peak surface and a second peak surface, the first peak surface and the second peak surface forming a first valley therebetween and being configured to contact the lower curved mounting surface.