3PCS 3-12mm 4-12mm 4-20mm HSS Straight Groove Step Drill Bit Set Titanium Coated Wood Metal Hole Cutter Core Drill Bit 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.