Yakamoz 7pcs HSS Countersink Drill Bits Set Screw Woodworking Chamfer Tool, 3-10mm The woodworking drill is made of HSS 4241, the middle chamfer drill body is NO. 45 steel. 7 Sizes in one drill bit set(3mm/ 4mm/ 5mm/ 6mm/ 7mm/ 8mm/ 10mm), which meet your different needs perfectly. Drilling length can be adjusted for various length screws simply loosening and tightening the setscrews. Chamfer is 5 flutes that can discharge the wood more rapid in the process of using, sink hole disposable drilled smooth, screw cap perfect embedded in the surface of work piece. Suitable for steel, aluminum & other metals, wood and plastic.