Keo 906-000-109 Combo Drill Countersink Size 4 Cobalt

Product Description

The KEO 906-000-109 is a combination drill and countersink tool machined from cobalt high-speed steel with a bright, uncoated finish. It is designed to drill a pilot hole and cut a 60-degree countersink in a single pass, reducing setup time in metalworking and fabrication operations. The body diameter measures 5/16 inches with a drill point diameter of 1/8 inches. The drill point angle is 118 degrees and the included angle for the countersink is 60 degrees. Overall length is 2-1/8 inches. The right-hand cutting direction suits standard drill press and CNC spindle operation. Cobalt construction provides heat resistance for cutting harder steels and stainless alloys.

This combo drill countersink is suited for machine shops, maintenance facilities, and fabrication environments where countersunk fastener clearances are required in steel, stainless steel, and other ferrous materials. It fits trade size 4 fastener applications. The double-end style and plain cutting edge make it compatible with standard drill chucks and collet holders. It is typically used by machinists, tool-and-die technicians, and maintenance mechanics working with countersunk screws in metal assemblies.

Key Features

• Cobalt high-speed steel construction for heat resistance when cutting hard alloys
• Combination design drills pilot hole and countersinks in a single operation
• 60-degree included angle matches standard countersunk fastener geometry
• 118-degree drill point angle for clean entry on ferrous metals
• Double-end style extends usable tool life
• Bright, uncoated finish - no coating buildup to affect close-tolerance countersinks

Compatibility

Designed as an OEM-style replacement or standard tooling selection for trade size 4 countersink applications in drill press, turret lathe, and CNC operations requiring a 60-degree countersink angle.

Installation Notes

This tool is installed by machinists and fabricators in a standard drill chuck or collet rated for the 5/16-inch body diameter. Secure workpiece firmly before operation to prevent tool deflection or chatter. Use appropriate cutting fluid for the workpiece material, particularly when machining stainless steel or hardened alloys. Inspect tool edges before each use and replace when visible wear affects countersink geometry.