General description The Step Drill Bit set includes 4 pieces with sizes 4-12mm, 4-20mm, and 4-32mm, designed for drilling holes in various materials such as steel, brass, wood, plastic, thin iron plates, aluminum, insulation boards, and PVC. Made from high-quality HSS, these bits are robust, rust-proof, and suitable for use with electric screwdrivers. The design allows for quick cutting of thin materials and provides extreme durability. Technical specifications Sizes: 4-12mm, 4-20mm, 4-32mm Material: High-Speed Steel (HSS) Twist drill size: 4mm Maximum thickness for use: 4mm Hardness limit: less than 25 HRC Usage These step drill bits are ideal for DIY projects, household tasks, and construction work. They are particularly effective for drilling holes in materials such as: Steel Brass Wood Plastic Thin iron sheets Aluminum Insulation boards PVC panels To ensure longevity, it is recommended to oil the bits before each use. Other information Note: These bits are not suitable for