Keo® Cobalt Zero Flute Countersinks (Series 919) Are Precision-Engineered Single-Flute Tools Designed For Chamfering, Deburring, And Countersinking Holes In A Wide Variety Of Materials, Including Hardened Steels, Non-Ferrous Metals, And Plastics. Their “Zero-Flute” Geometry — A Cutting Edge Formed Directly By The Tip Intersection Rather Than A Conventional Flute — Ensures Smooth, Chatter-Free Performance And A Highly Polished Finish. They Are Constructed From Cobalt High-Speed Steel (Hss-Co), Which Offers Greater Heat And Wear Resistance Than Standard Hss, Making Them Suitable For Demanding, High-Speed Machining Applications.

• Manufactured from premium M42 Cobalt for superior heat and wear resistance.
• Zero-flute (single-edge) design ideal for deburring, chamfering, and countersinking soft or brittle materials.
• Produces smooth, chatter-free finishes with excellent surface quality.
• Perfect for use on non-ferrous metals, plastics, and composites.
• Precision-ground cutting edge ensures clean, concentric holes.
• Excellent chip evacuation due to open flute design.
• Self-centering action reduces chatter and tool walking.
• Works effectively in hand-held drills, drill presses, or CNC equipment.
• Designed for precision deburring and countersinking in production or maintenance settings.Made in the USA for consistent quality and durability.
• TiN (Titanium Nitride) coated which enhances tool performance with increased hardness, reduced friction, and excellent wear resistance. Ideal for general-purpose machining, TiN extends tool life and delivers smoother cutting on materials such as steel, aluminum, and stainless steel.
• This photo of this item only REPRESENTS this tool, please read the items specifics for detailed information.

This item is part of our complete offering of ARCH Cutting Tools, trusted for high-performance CNC machining across drilling, milling, holemaking, and indexable applications. Explore Patriot HP Cutting Tools for advanced solid carbide and high-performance machining solutions, KEO Cutting Tools for precision countersinks, center drills, and holemaking tools, Ultra-Dex Cutting Tools for productive indexable milling, drilling, and insert-based machining, and Revere Cutting Tools for high-performance carbide end mills and milling solutions. Visit our main ARCH Cutting Tools page to compare tool styles, coatings, geometries, and performance options to find the right solution for your application.