12 PCS Countersink Drill Bit Set, 82° Counter Sink Drill Bits for Wood, #4#6#8#10#12, Magnetic Extension Bit Holder with Adjustable Depth, Countersink bits, Hex Shank for Electric Drill

• Two-Flute Cutting Structure: This countersink drill bit set uses a dual-edge cutting design that reduces vibration during drilling. Compared to single-blade bits, the two-flute structure allows smoother entry into wood surfaces. Large or deep countersinks can be completed with fewer passes, saving time on repetitive woodworking tasks.
• 12-Piece Component Combination: The set contains 5 countersink bits covering #4, #6, #8, #10, #12 sizes, plus 5 replaceable drill bits. A 60mm magnetic extension bit holder and a hex wrench are also included. The storage case keeps all components organised and prevents loss during transport or job site work.
• Titanium-Coated High-Speed Steel Construction: Each countersink bit is made from high-speed steel with a titanium coating that resists wear. The stepped chamfer blade design reduces friction when entering wood, allowing repeated use without edge dulling. This construction handles both softwood and hardwood drilling applications.
• 82-Degree Sharp Blade for Clean Holes: Sharp blades combined with an 82-degree countersink angle produce clean pilot holes for flush screw seating. One operation accomplishes drilling, countersinking, and counterboring at the same time. This three-in-one function reduces the need to switch tools during installation work.
• 1/4-Inch Hex Shank for Tool Compatibility: The hex shank design fits impact drills, hand drills, bench drills, and electric drills. The magnetic extension bit holder provides additional reach for confined spaces. Adjustable depth settings allow matching countersink depth to different wood board thicknesses.

This tool set creates countersunk pilot holes in wood before screw installation. Suitable for woodworking, furniture assembly, door frames, and similar tasks. Read below for step‑by‑step instructions and notes.  How to use: Select correct bit size — Match countersink bit to screw number (#4, #6, #8, #10, or #12). Set includes five countersink bits and five replaceable drill bits, each labelled with matching screw size.  Attach to drill — Bits have a 1/4‑inch hex shank that fits hand drills, impact drills, or bench drills. Tighten chuck securely. For narrow spaces, use the 60mm magnetic extension holder. Connect bit to holder first, then insert holder into drill.  Adjust countersink depth — Set depth stop according to wood thickness. Turn clockwise to increase depth, counter‑clockwise to decrease. Adjust until screw head sits flush with wood surface.  Start drilling — Align bit with screw position. Start drill and feed steadily at constant speed. The 82‑degree countersink angle lets the bit drill pilot hole, create countersink, and chamfer edge in one motion. Two‑flute design reduces wobbling and keeps hole edge clean.  Clean and store — After several holes, remove wood chips from bits using a brush or compressed air. When finished, place all bits and accessories into storage case slots. Do not store magnetic extension holder directly against other metal tools to prevent magnetism loss.  Important notes:  Extended use on hardwood not recommended – overheating may reduce cutting performance  Wear safety goggles to protect against wood chips  Keep drill speed between 1500‑2500 RPM; higher speeds may scorch wood  Hold drill perpendicular to wood surface for accurate countersink angle  Replace worn drill bits only with same‑size spare from this set