Irwin 12412 5/8" Single Flute High-Speed Steel Metal Countersink

Smooth performance for larger fasteners. The Irwin 12412 is the industrial-scale solution for creating perfectly seated, flush finishes in heavy-duty applications. While smaller bits struggle with large-diameter holes, the 5/8" profile of the 12412 is engineered to handle industrial bolts and lag screws with the same "chatter-free" precision that pros expect from the Irwin single-flute lineup.

Engineered for High-Torque Precision:

• Chatter-Free Single Flute: The innovative single-edge design eliminates the vibration and "bouncing" that often occurs with multi-flute bits. This ensures a continuous, surgical cut and a mirror-smooth finish every time.
• 82° Industrial Point: Precision-ground to an 82-degree angle, the industry standard for flat-head screws and bolts, ensuring your fasteners sit perfectly flush without protruding edges.
• Premium High-Speed Steel (HSS): Forged from industrial-grade HSS for maximum edge retention and heat resistance, even when working through mild steel, alloy steels, and non-ferrous metals.
• Superior Chip Clearance: The single-flute geometry allows for rapid chip evacuation, preventing heat buildup and clogging during deep-hole countersinking.
• Universal 1/4" Shank: Designed for maximum compatibility with standard drill chucks, providing a secure, non-slip grip for hand-drilling or drill press operations.

Specifications:

• Part Number: 12412
• Diameter: 5/8" (0.625 in)
• Angle: 82 Degrees
• Flute Count: Single Flute
• Material: High-Speed Steel (HSS)

Finish big projects with a clean edge. The Irwin 12412 5/8" Countersink is the professional’s choice for large-scale metalworking and heavy timber framing. Don't settle for rough, uneven holes—get the smooth, burr-free finish your work deserves. Order the 5/8" Irwin 12412 from edmfast.com and perfect your layout.

The "Industrial Fastening" Bundle 

Large Diameter Precision. Professional Protection. Site-Ready Storage. Pair your 5/8" Irwin Countersink with these heavy-duty site upgrades.

[→ SHOP ALL METALWORKING & DRILLING ACCESSORIES HERE]

• [Irwin 12411 1/2" Single Flute Countersink] – The Complete Set. Most projects require a variety of fastener sizes. Adding the 1/2" companion bit ensures you are ready for standard hardware while the 5/8" handles the heavy loads.
• [Milwaukee Cobalt Drill Bit Sets] – The Hard-Metal Starter. Create the perfect pilot hole in stainless steel or cast iron before finishing with your Irwin countersink. Cobalt is essential for high-heat, high-friction metalwork.
• [Milwaukee 48-22-8435 PACKOUT™ Compact Organizer] – The Precision Vault. Protect your HSS cutting edges from dulling in your tool bag. This slim organizer keeps your countersinks vertical and easy to find on a busy site.
• [3M™ SecureFit™ 400 Series Anti-Fog Safety Eyewear]– Impact Protection. Large-diameter countersinking generates larger, hotter metal spirals. These glasses offer the high-impact protection and anti-fog technology needed for long drilling sessions.
• [Watson 005 Flextime™ Leather Work Gloves] – Dryhide™ Water Resistance. Maintain the tactile grip required for precision drilling while protecting your hands from sharp metal burrs and heat.