12PCS M35 Cobalt Step Drill Bits 1-6mm Self-Centering Split Point Drills for Stainless Steel Hardened Metal Wood Plastic

一、Product Description12pcs cobalt twist drill bits cover sizes 1mm/2mm/3mm/4mm/5mm/6mm, 2 pieces per size. Made of wear-resistant metal with sharp pointed tip and deep spiral flutes for fast chip removal. Flat shank prevents slipping in drill chucks. Compatible with metal, wood and plastic. Hard, sturdy and precise for daily drilling jobs. It also works to extract broken & rusted bolts and damaged screws. Drill vertically straight to get neat round holes; tilted drilling causes rough edges and bit damage. Packed in transparent storage case for easy classification and carry.二、Correct Step Drill Usage Guide1. PreparationsConfirm workpiece material (metal/wood/plastic) and pick matched drill diameter.Firmly clamp workpiece to avoid shaking during drilling. Mount drill bit into electric drill, fully lock flat shank to stop slipping.Wear safety goggles; keep hands away from drill path.2. Drilling Core OperationKeep drill perpendicular (90°) to workpiece surface at all times, no tilt. Tilting leads to irregular holes, bit bending or breakage.Start drill at low speed to position the drill point steadily on the marked hole spot. Gradually increase rotating speed.Apply steady, moderate downward pressure. Do not push hard forcibly; let spiral flutes discharge metal shavings/wood debris naturally.For thick hard metal: lift the bit up periodically to clear chips, prevent overheating and bit burning. Add cutting fluid on metal for cooling and smoother drilling.3. Broken Bolt Removal StepsSelect a drill size smaller than the broken bolt inner diameter.Drill straight and centered into the broken bolt head carefully.Reverse drill rotation to bite the metal, pull out the stuck damaged bolt slowly.4. Post-use MaintenanceWipe away metal dust and wood scraps, store all bits sorted in the plastic case to avoid collision and rust.