Precision Twist Drill 5996091 Cobalt Screw Machine Drill Bit

Product Description

The PRECISION TWIST DRILL 5996091 is a cobalt screw machine length drill bit designed for high-performance drilling in hard and tough materials. Part of the M41CO series, it carries a 135-degree split point with web thinning for fast, accurate starts without a center punch. The straight-cylindrical shank seats securely in standard drill chucks and CNC machine tool holders. At 1.75 inches overall length with a 0.75-inch flute, this stub-length geometry delivers added rigidity and reduced deflection compared to jobber-length bits, making it well suited to precision, high-cycle production drilling operations.

This bit is intended for drilling hard materials including alloy steels, stainless steel, cast iron, titanium, and other work materials that demand elevated heat resistance and edge retention. The M41 high-speed cobalt alloy construction maintains hardness at elevated cutting temperatures generated in production drilling environments. It fits screw machine, turret lathe, drill press, and CNC machining center applications where short overall length and rigidity are required. Wire gauge size 42 corresponds to 0.0935 inches diameter, a common size for tapping undersized holes and precision clearance applications in metalworking and manufacturing trades.

Key Features

• M41 cobalt high-speed steel construction for heat resistance in hard-material drilling
• 135-degree split point with web thinning for self-centering starts and reduced thrust
• Screw machine (stub) length at 1.75 inches overall for increased rigidity and reduced deflection
• Regular spiral flute with 2.5xD flute-to-diameter ratio for efficient chip evacuation
• Straight-cylindrical shank compatible with standard chucks and collets
• Tapered web configuration with right-hand cut; meets ANSI standards

Compatibility

Designed as a heavy-duty OEM-style screw machine drill bit for use in metalworking applications requiring wire gauge 42 (0.0935 inch diameter) tooling in standard straight-shank drill chucks, collets, and CNC tool holders.

Installation Notes

Installation and tool changes should be performed by qualified machinists or tooling technicians with the machine powered down and locked out per OSHA lockout/tagout procedures. Secure the shank fully within the chuck or collet before operation and verify runout with a dial indicator in precision applications. Do not exceed the recommended feed and speed parameters for the workpiece material and machine setup. Cutting fluid or coolant is recommended when drilling hard alloy steels and stainless to extend tool life, noting this bit does not have coolant-through capability.