They are for use in general machine tapping or CNC tapping.
Black oxide high-speed steel dill bits are ideal for production, maintenance or portable drilling jobs and are surface treated with abrasion-resistant black oxide.. Black oxide high-speed steel drill bits are a dependable, general purpose drill designed to perform in a broad range of materials in the iron and steel families.50mm HSS Drill Bit Kit High speed steel hand taps can be used for making new threads or re-threading damaged threads.