Precision Twist Drill 5995966 Cobalt Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5995966 is a cobalt screw machine length drill bit designed for high-performance drilling in hard and difficult-to-machine materials. Built from M35 cobalt high-speed steel, this 33/64 inch (0.5156 inch) diameter bit features a 135-degree split point that reduces walking on contact and requires no center punch on most setups. The spiral flute geometry and web-thinned, tapered web construction promote efficient chip evacuation and reduced thrust. This bit is suited for machinists, tool-and-die shops, and industrial maintenance technicians working with stainless steel, hardened alloys, and similar hard stock.

The 5995966 is a screw machine length bit, meaning it is shorter than a jobber-length bit for improved rigidity and reduced deflection in turret lathes, drill presses, and CNC machining centers. Its shorter overall length makes it a practical choice in tight-clearance setups or multi-spindle screw machine applications. The straight cylindrical shank accepts standard drill chucks without modification. This bit is part of the Series M40CO line, which is manufactured to ANSI standards for consistent dimensional accuracy across production runs.

Key Features

• M35 cobalt high-speed steel construction for heat and wear resistance in hard materials
• 135-degree split point reduces entry force and eliminates center-punch requirement on most materials
• Web-thinned, tapered web lowers cutting resistance and improves chip flow
• Screw machine length body provides added rigidity and reduced deflection versus jobber-length bits
• 2-flute spiral geometry with 2.5xD flute-to-diameter ratio for effective chip evacuation
• ANSI-compliant dimensions ensure drop-in compatibility with standard toolholding systems

Compatibility

Designed as a screw machine length replacement drill bit for use in standard drill chucks accepting straight cylindrical shanks, compatible with drill presses, turret lathes, and CNC machining centers requiring a 33/64 inch diameter bit in the 0.5000 to 0.6000 inch drill bit size range.

Installation Notes

Installation is performed by machinists or maintenance technicians using a standard keyed or keyless drill chuck. Ensure the machine spindle is fully stopped and locked out before inserting or removing the bit. Confirm shank seating is secure and the chuck is tightened evenly to prevent runout. Follow applicable ANSI and shop safety standards for drilling speeds and feeds appropriate to the workpiece material.