Precision Twist Drill 5999749 Cobalt Drill Bit 5/16 in

Product Description

The PRECISION TWIST DRILL 5999749 is a cobalt-grade, jobber-length drill bit designed for drilling through hard and abrasive materials in industrial and trade applications. Built to the R88CO series standard, it features a 135-degree split point that reduces walking and requires no center punch on most surfaces. The straight-cylindrical shank measures 5/16 inches in diameter and seats securely in standard three-jaw chucks. At 4.5 inches overall length with a 1.625-inch flute, this bit is sized for general-purpose through-hole drilling in production and field environments. Cobalt construction with an oxide/bronze finish provides heat resistance and extended tool life compared to standard high-speed steel bits.

This drill bit is suited for drilling steel, stainless steel, cast iron, non-ferrous metals, superalloys, and titanium. It is a practical choice for HVAC installers, pipefitters, sheet metal workers, and machinists who regularly work with tough or work-hardening materials. The right-hand spiral flute and web-thinned tip make it effective in both handheld drill drivers and drill press setups. The regular spiral type provides balanced chip evacuation across the supported workpiece material range.

Key Features

• Cobalt high-speed steel construction resists heat buildup when drilling hard and abrasive materials
• 135-degree split point reduces drill walk and lowers thrust force required at entry
• Web-thinned, tapered web design improves cutting efficiency and chip clearance
• Oxide/bronze finish adds surface hardness and corrosion resistance
• Right-hand, regular spiral flute with 2-flute configuration for consistent chip evacuation
• Meets NAS 907 specification for dimensional and performance standards

Compatibility

Designed as a general-purpose jobber-length replacement drill bit compatible with any standard 3-jaw chuck or drill press accepting a 5/16-inch straight-cylindrical shank. Suitable for workpiece materials coded P, M, K, N, and S including steel, stainless steel, cast iron, non-ferrous metals, and superalloys.

Installation Notes

Install in a compatible chuck and confirm the shank is fully seated and the chuck key is removed before starting the drill. Always wear eye protection and secure the workpiece before drilling. Use cutting fluid or coolant when drilling stainless steel, superalloys, or titanium to prevent work hardening and premature bit wear. Inspect the cutting edges before each use and replace the bit if chipping or excessive wear is observed.