A metal cutting insert comprises a carbide substrate, and at least one body of superhard abrasive material, such as PCD or PCBN, bonded to an edge surface of the substrate and extending from one side surface to the other side surface of the substrate. There can be a plurality of superhard bodies disposed at respective corners of the substrate. The abrasive material is applied to the substrate in a container and then sintered and simultaneously bonded to the substrate by an elevated pressure/temperature step. Inserts can be made in rod form (i.e., in one piece) and then the rod can be transversely sliced into thin inserts; or the inserts can be made in separate pieces, with or without separators within the container.