The Hinge Drill Bit is Made of Cemented Carbide That Makes the Cutting Sharper, Lasting Durability, Unimpeded Chip Removal, and Has Excellent Boring Ability and Excellent Boring Performance. The Center Spur of Each Bit Guarantees Accurate Drilling and Prevents Walking and Wobbling During Operation, Create Perfectly Round and Accurate Holes with The Center Spur Design.It's Head Adopt Arc Curve Double-edged Design, Rapid Removal of Waste and That Make Sure Your Work with Efficiency. A Depth Stop can be Fixed on the Shank Which Keeps You From Drilling too Deep, Limited Depth From 15mm to 40mm. Easily and Conveniently Dip Cup Hole on the Wardrobe Door or Desk by Yourself With the Hinge Drilling Jig, Suitable for Their Own Home Operation, Even you are not a Professional, You can Quickly Locates Drill Center Points for Hinges and Mounting Plates.