Kennametal 3640709 Screw Machine Drill Bit 8mm Carbide

Product Description

The KENNAMETAL 3640709 is a screw machine length drill bit designed for high-performance drilling in demanding materials. Built from solid carbide with a TiAlN coating, this bit handles high temperature alloys and stainless steel where standard HSS tooling fails. It measures 8.00 mm in diameter with a 140-degree split point and an overall length of 79.00 mm, making it a compact, stub-length tool suited for rigid setups in CNC machining centers and screw machines. The web-thinned geometry reduces thrust load at entry. Coolant-through capability allows internal delivery of cutting fluid directly to the tip, extending tool life in deep-hole applications. This bit is intended for use by machinists and toolroom professionals working in production environments.

This drill bit is suited for production drilling in materials that work-harden quickly or generate high cutting temperatures, including stainless steel grades and nickel-based high temperature alloys. The screw machine length format provides increased rigidity compared to jobber-length drills, reducing deflection in short-reach applications. The straight cylindrical shank accepts standard drill chucks and toolholders with a matching 8.00 mm bore. The 3xD flute-to-diameter ratio and 29.00 mm maximum drilling depth make it appropriate for through-holes and blind holes in plate, bar stock, and machined components encountered in aerospace, medical, and industrial manufacturing.

Key Features

• Solid carbide construction for rigidity and heat resistance in hard-to-machine materials
• TiAlN coating improves oxidation resistance and extends tool life in high-temperature cutting conditions
• 140-degree point angle reduces thrust and is optimized for stainless steel and high temperature alloys
• Web-thinned, parallel web design lowers entry force and improves chip evacuation
• Coolant-through design delivers cutting fluid internally to the cutting edge
• Screw machine length provides maximum rigidity in short-reach and close-tolerance drilling setups
• Conforms to DIN 6537K specification for dimensional consistency

Compatibility

Designed for use in CNC machining centers, screw machines, and drill presses with toolholders accepting an 8.00 mm straight cylindrical shank. Primary workpiece materials are high temperature alloys and stainless steel per series B291-YPL application guidelines.

Installation Notes

Installation and use should be performed by qualified machinists familiar with carbide tooling requirements. Secure the straight shank in a properly sized collet or drill chuck before operation, and verify runout is within acceptable limits, as carbide is brittle and sensitive to lateral loading. Enable coolant-through supply before starting the cut when internal coolant is available. Do not use this bit in hand-held drill applications; carbide tooling requires rigid machine setups to prevent chipping or fracture.