Precision Twist Drill 5996603 Cobalt Drill Bit Letter C

Product Description

The PRECISION TWIST DRILL 5996603 is a screw machine length cobalt drill bit sized to Letter C (0.2420 inches) with a 135-degree split point and web-thinned tip. Built from M42 cobalt high-speed steel, this bit is engineered for high-performance drilling in hard and tough materials where standard HSS bits wear prematurely. The straight-cylindrical shank measures 0.2420 inches in diameter and the overall length is 2.5 inches, making it well-suited for close-quarters drilling in machine setups. Right-hand cut with a regular spiral and spiral flutes, it delivers reliable chip evacuation at production drilling speeds. Machinists, tool-and-die workers, and maintenance technicians install this bit in drill presses, CNC machines, and screw machines.

This bit is designed for drilling hard materials including hardened steels, stainless steel, cast iron, and other high-strength alloys where heat resistance and edge retention are required. The screw machine length profile — shorter than a jobber bit — provides added rigidity and reduced deflection, making it a common choice for production environments and repetitive-cycle machining operations. The 1.375-inch flute length at a 2.5xD flute-to-diameter ratio supports efficient chip clearing through the cut depth.

Key Features

• M42 cobalt high-speed steel construction for heat and wear resistance in hard materials
• 135-degree split point with web thinning reduces walking and lowers thrust requirements
• Screw machine length (2.5 inches OAL) adds rigidity and minimizes deflection
• Right-hand cut, regular spiral with tapered web configuration for consistent chip flow
• Straight-cylindrical shank (0.2420 inches) fits standard drill chucks and collets
• Meets ANSI standards; M42 grade rated for heavy-duty performance

Compatibility

Designed as an OEM-style replacement or direct tooling selection for screw machines, drill presses, and CNC drilling operations requiring a Letter C (0.2420 inch) straight-shank cobalt drill bit in screw machine length.

Installation Notes

Installation is performed by machinists and maintenance technicians using standard drill chucks or collet holders rated for the 0.2420-inch shank diameter. Ensure the drill press or machine spindle is fully stopped and locked out before changing bits. Secure the shank firmly in the chuck with no runout before beginning a cut. Cutting fluid or coolant is recommended when drilling hard alloys to extend tool life, even though this bit does not support through-coolant delivery.