Abstract: A tungsten carbide boring bar has a mechanism for securing the cutter insert in a passage in the boring bar. The boring bar has a transverse bore through the body of the tool. A steel plug is received in the bore closely adjacent the position of the insert. The plug has a central threaded passage. A retainer is threadably received in the plug and has an inner end seated in a notch in the shank of the insert to retain the tool in position, and an outer end adapted to receive a turning tool.

Abstract: A cutting tool that includes a boring bar, a cutter insert, and a mechanism for retaining the cutter insert on the bar. The bar is formed of tungsten carbide. A relatively short steel retaining element is mounted in the rear end of the bar. Internal threads are formed in the steel element but not in the tungsten carbide bar. The retaining mechanism includes an elongated threaded rod extending longitudinally within the bar into a retainer notch formed in the side surface of the shank of a cutter insert.