Step Drill Bit AWTools M2-TiAlN spiral 4–20 mm, model AW40931BL

AWTools step drill bit model AW40931BL is a spiral-fluted cone bit made from M2 high-speed steel with a TiAlN (titanium aluminium nitride) surface coating. The stepped cutting range from 4 to 20 mm allows progressive enlargement of holes in sheet metal and other thin materials without frequent tool changes. Spiral geometry improves chip evacuation and contributes to smoother cutting and longer tool life when used under recommended conditions.

Advantages

The TiAlN coating increases surface hardness and heat resistance compared with uncoated HSS, helping to maintain sharp cutting edges during extended drilling. Spiral flutes promote efficient chip evacuation and reduce clogging in pierced material. The stepped profile enables quick switching between hole diameters and reduces setup time for multi-size hole patterns. The bit’s HSS construction balances toughness and wear resistance for typical workshop and maintenance environments.

Suitable for

• Drilling and enlarging holes in sheet metal (steel, stainless steel thin sheets, aluminium)
• Electrical, plumbing and HVAC panel work requiring several hole diameters
• Maintenance, repair and fabrication tasks in workshops and service vehicles
• Thin plastics and composite panels where stepped holes are required

Key specifications

• Material: M2 high-speed steel (HSS)
• Coating: TiAlN (titanium aluminium nitride)
• Cutting range: 4–20 mm (stepped)
• Flute type: Spiral flutes for improved chip removal
• Shank type: Cylindrical shank for standard drill chucks
• Application: Progressive drilling in thin materials and sheet metal

How to use

Secure the step drill bit in a drill or drill press chuck suitable for the shank diameter and ensure the chuck is tightened firmly. Mark the hole center and start drilling at low speed to establish a clean entry point, then increase speed moderately while applying steady axial pressure. For sheet metal and thin materials, use lubricant or cutting fluid when drilling harder alloys to reduce heat buildup and extend tool life. Progress through the stepped diameters until reaching the required hole size, withdrawing occasionally to clear chips when necessary.

Usage recommendations

Use moderate feed and appropriate cutting fluid for stainless steel or hardened materials. Avoid excessive speeds that generate heat beyond the TiAlN coating’s limits. Inspect the bit for wear before precision work and replace when cutting edges become dulled to maintain hole quality.