Latest 3Pcs HSS Nitriding Black Step Drill Bits 4-12mm 4-20mm Titanium Coated Wood Metal Hole Cutter Core Drilling Bit Tools Set

Hex shank nitrided black straight groove step drill small 3pcs pagoda drill bit set Material: high speed steel Specification: 4-20: 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm, 20mm 3-12: 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm 4-12: 4mm, 6mm, 8mm, 10mm, 12mm Surface treatment: Nitride black Application: Suitable for drilling and hole reaming processing of wood, aluminum, plastic board, insulating board and other materials with a thickness of less than 5mm.