Leitz Internal Door (I-Door) combination carbide/diamond insert tooling utilizes a light-weight aluminum body and a combination of standard carbide inserts and unique diamond inserts. This innovative design maximizes tool life and exposed edge finish quality in the manufacture of interior doors, typically constructed of very hard/abrasive external surfaces (hard fiber or fiberglass) and relatively soft core material. Replaceable diamond inserts at the top and bottom of the tool process the top and bottom surface laminates, while standard carbide inserts process the softer core material. The result is extremely smooth edge quality, only accomplished otherwise by additional sanding. The diamond and carbide inserts are easily changed in house, eliminating the need for multiple heads in rotation. Precise insert seating results in fast and easy knife changes and eliminates the need to reset the machine—resulting in minimal machine downtime and significantly increased throughput.