Hole drilling woodworking hole Screw Flute Countersink Drill Bit Set Tool Features:Special designed steel counter sleeve countersinks or counter bores pilot hole.Drilling length can be adjusted for various length screws simply by loosening and tightening the setscrew.It is suitable for drilling machines with chuck, for drilling on hard wood or wooden floor.Unique Design: Three-Pointed design can quickly and accurately drill a smooth hole. Five-edged chamfer design will fast discharge chips from the hole on both sides automatically.High Quality Material: High-Speed Steel is high hardness, high wear resistance, high heat resistance and high strength to go sharp drilling and be easy to break.Material:High speed steelSize:as the pictuce shownPackage included:7pcs x woodworking chamfers1pc x hex shank