This set of spiral-shaped, nitrided high-speed steel step drill bits is designed for enlarging drilled holes and is suitable for PVC sheets, metal sheets, and woodworking. Available sizes: 4-12 mm.

Material: 4241 high-speed steel; Shank type: Round triangular shank; Surface treatment: Black nitriding. Double helical flute design: The double flute design effectively eliminates burrs, dust, and debris for a clean cut. Adding cold water during drilling prolongs the drill bit's life. Recommended drilling speed: 250 rpm. Suitable for thin iron sheets, aluminum sheets, insulation panels, and PVC panels up to 5 mm thick. This drill bit set includes 3 sizes (4-12 mm, 4-20 mm, and 4-32 mm) to perfectly meet your various needs. Quantity: 3 pieces.