HSS Counterbore End Mill Milling Cutter Bit Set (M3–M8)

Protruding bolt heads, uneven fastener seating, and rough counterbore recesses shouldn't compromise the clean finish or structural strength of your woodworking, plastic fabrication, or metal machining projects. Machine flush, professional recessed socket cap bolt holes effortlessly with our HSS counterbore end mill milling cutter bit set, engineered with precision pilot guides for smooth, chatter-free counterboring.

Crafted from premium High-Speed Steel (HSS), these countersunk milling cutters deliver high hardness, heat resistance, and long-lasting edge retention through wood, aluminum, brass, and plastics. Each bit features a precision pilot tip that aligns with your pre-drilled pilot hole to keep the cutter centered, preventing tool chatter and off-center cutting. Available in metric thread sizes ranging from M3 to M8, these straight-shank end mill bits fit standard drill presses, milling machines, and power drills to produce clean, flat-bottomed counterbores for socket head cap screws.

Key Features

• High-Speed Steel (HSS) Build: Heat-treated HSS construction resists thermal wear and maintains sharp cutting edges for clean, burr-free cuts.

• Integrated Pilot Guide Tip: Pilot alignment pin sits inside pre-drilled holes to guide the cutter for centered, stable counterboring without chatter.

• Flat-Bottomed Counterbore Design: Creates clean 90° flat-bottom recesses so socket head cap bolts and fasteners sit completely flush or below the surface.

• Standard Metric Sizes (M3–M8): Precise sizing matches standard metric cap screw dimensions for exact clearance holes and bolt seat depths.

• Universal Straight Shank: Fits standard drill presses, CNC milling routers, lathe tailstocks, and heavy-duty hand drills.

• Multi-Material Utility: Ideal for machining counterbores in hardwood, plywood, aluminum, brass, acrylic, and structural plastics.

Why Choose Our HSS Counterbore Milling Cutters Unlike standard step drills or large drill bits that leave angled, uneven hole bottoms and tear up material edges, our pilot-guided HSS counterbore mills cut true 90° flat-bottomed recesses. They ensure your socket head bolts seat perfectly square every time.

Perfect For

• Machinists, woodworkers, and fabricators hiding bolt heads flush in custom fixtures and furniture.

• CNC operators and toolmakers machining precise fastener pockets in aluminum, brass, and plastics.

• DIY enthusiasts upgrading workshop jigs, engine parts, and custom mechanical assemblies.

Product Specs

• Quantity: 1 Piece / Available Sizes

• Material: Premium High-Speed Steel (HSS)

• Sizes Available: M3, M4, M5, M6, M8

• Shank Type: Straight Shank

• Application: Socket Head Cap Screw Recessing, Wood, Metals, & Plastics

Machine Flush Fastener Holes Today Achieve clean, professional recessed bolt seats on all your machining and woodworking projects. Order your HSS counterbore end mill milling cutter bit today!