Accupro 77712586 Carbide Screw Machine Drill Bit 0.25 in

Product Description

The ACCUPRO 77712586 is a solid carbide screw machine length drill bit designed for high-performance drilling in demanding metalworking applications. At 0.25 inches (1/4 inch) in diameter, this bit features an AlTiN (aluminum titanium nitride) coating, a 140-degree point angle, and a web-thinned parallel web configuration. The 2-flute spiral design promotes efficient chip evacuation, and coolant-through capability supports extended tool life in production environments. Licensed trades and machining professionals rely on this geometry for tight-tolerance work in hard materials.

This drill bit is engineered for cutting alloy steel, cast iron, and stainless steel. The screw machine (stub) length profile provides added rigidity compared to jobber-length bits, making it well-suited for CNC machining centers, drill presses, and manual machines where reduced deflection matters. The straight-cylindrical shank seats reliably in standard chucks and collet systems. Maximum drilling depth is 0.75 inches, making it appropriate for through-holes and blind holes in typical production setups.

Key Features

• Solid submicron carbide construction for hardness and wear resistance in ferrous materials
• AlTiN coating reduces heat buildup and extends tool life in high-speed cutting
• 140-degree point angle with web thinning reduces thrust force and improves self-centering
• Coolant-through design supports internal chip flushing in production drilling
• Right-hand cut, 2-flute spiral flute for efficient chip evacuation
• Straight-cylindrical shank compatible with standard drill chucks and collet holders

Compatibility

Rated for primary workpiece materials including alloy steel, cast iron, and stainless steel. Designed for use in standard straight-shank drill chucks and collet systems accepting an 8 mm (approximately 0.315 inch) shank diameter.

Installation Notes

Install and remove drill bits only with the spindle fully stopped and the machine isolated from power. Secure the straight-cylindrical shank fully in the chuck or collet before operation to prevent runout. Use appropriate cutting fluid or coolant when drilling stainless steel or hardened alloy steel to preserve coating integrity and edge life. Inspect the cutting edge for chipping or wear before each use, as carbide tooling is brittle and may fracture if subjected to side loading or interrupted cuts beyond its rated capacity.