Cemented carbide inserts for machine tools; tools and machines for metalworking; cutters for gears (machine tools); thread milling cutters (machine tools); tool grinders; gear cutters (machine tools); milling cutters (machine tools); polycrystalline diamond compact [PDC] bits for drilling machines; polycrystalline diamond cutting tools for machining manufacturing parts; polycrystalline diamond-cutting machines for cutting work pieces