Precision Twist Drill 5995978 Cobalt Drill Bit 45/64

Product Description

The PRECISION TWIST DRILL 5995978 is a screw machine length cobalt drill bit engineered for high-performance drilling in hard and abrasive materials. Sized at 45/64 inches (0.7031 inches) in diameter, it features a 135-degree split point that reduces walking and cutting force on entry. The regular spiral flute with a 2.5xD flute-to-diameter ratio promotes efficient chip evacuation. Web thinning and a tapered web configuration improve penetration in tough workpiece materials. This bit is built to ANSI standards and carries an M40 material grade designation, making it a heavy-duty option suited for demanding production and maintenance environments.

This drill bit is designed for use in hard materials where standard HSS tooling loses its edge too quickly. The screw machine length profile — shorter overall than a jobber bit — provides added rigidity and reduced deflection, which is especially useful in drill press, CNC, or lathe-tailstock applications. It is a solid choice for machinists, maintenance technicians, and fabricators working with hardened steels, stainless, and similarly tough stock. The straight-cylindrical shank fits standard drill chucks without adapters.

Key Features

• Cobalt construction with M40 material grade for heat and wear resistance in hard materials
• 135-degree split point reduces thrust and self-centers on entry without a center punch
• Web-thinned, tapered web configuration improves cutting efficiency and reduces torque demand
• Screw machine length body (4-3/4 inches overall, 3-inch flute) delivers rigidity and reduced deflection
• Right-hand spiral flute promotes consistent chip evacuation during through-hole drilling
• Meets ANSI standards; heavy-duty grade rated for production and repeat-use applications

Compatibility

Designed as a direct-fit replacement or standard tooling selection for any drill press, CNC machining center, or hand drill with a chuck accepting a straight-cylindrical shank at 0.7031 inches diameter; rated for hard workpiece materials per Series M40CO specifications.

Installation Notes

Installation is performed by qualified machinists or maintenance technicians familiar with rotating cutting tools. Secure the straight-cylindrical shank firmly in the chuck before operation and verify runout before engaging the workpiece. Ensure the machine spindle is at a full stop before bit changes. Coolant-through is not supported on this bit; use external flood or mist coolant when drilling hard materials to manage heat buildup.