precision drilling:Accurately drill pilot holes in hinges, handles, drawer slides, and other hardware, to the screws are straight and for proper hardware installation.Sharp: 135 degree oblique edge the head of a bit,make the drill more rapid drilled into the position of hinge holesWood chips are automatically discharged:Sawdust will be automatically drained from both sides of the holes, without drill blocked,you 't have to remove wood chips , effectively increasing your workCombinate with punch: Automatic center punch is more convenient as they 't require a hammer,stop drill bits from wandering on plain surfaces,great for repetitive punching or riveting,adjustable for light or heavy strokes,perfect for DIY users tool kit.These Self Centering Bits are great for drilling perfectly centered holes in hinges, hardware, or any time that you need accurately placed holes. The beveled edge tips keeps centered even if the hole is slightly smaller than standard home door hardware. They have drill bit depth adjustments and recessed hex shafts for quick .Pattern Name:4pcs Self Centering Drill+punchDescription:1. Material:HSS2. Color: Sliver3. They come with HSS drill bits that are replaceable with jobber bits if ever needed.4. They come in the hinge screw sizes 5/64, 7/64, 9/64, 11/64 inch5. Spring loaded outer guide keeps the high-speed drill centered6. Fit for drilling pilot holes in cabinet and door hinges and door butts7. Self centering for consistently accurate pilot holesSize:5/64 inch: Hole diameter is about 2 mm,Use about 2.2 - 2.8 mm tapping screw7/64 inch: Hole diameter is about 2.8 mm,Use about 3 - 3.5 mm tapping screw9/64 inch: Hole diameter is about 3.5mm,Use about 4 - 4.5 mm tapping screw11/64inch: Hole diameter is about 4.5mm,Use about 5 - 5.5 mm tapping screwNote: appropriate adjustments according to the hardness of wood when opening,if wooden ,you can a smaller size,if hard wood, corresponding or a bigger size.Package include:4 pcs HSS Self Centering Hinge Drill Bits Set Door Cabinet1 pcs Gold Center Hole PunchOnly the above package content, other products are not included.Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.