Precision Twist Drill 5999019 Cobalt Jobber Drill Bit Letter G

Product Description

The PRECISION TWIST DRILL 5999019 is a cobalt high-speed steel jobber-length drill bit sized to Letter G (0.2610 inches decimal equivalent). It features a 135-degree split point with web thinning for fast engagement and reduced walking on hard workpieces. The oxide and straw finish improves surface hardness and heat resistance. With a right-hand spiral flute and straight cylindrical shank, it is suited to standard drill chucks on benchtop, floor-standing, and handheld power tools. Machinists, tool-and-die workers, and maintenance technicians install this bit for general-purpose drilling in steel, cast iron, nonferrous metals, and plastics. The 2-flute design provides adequate chip clearance at typical feed rates.

This drill bit is designed for drilling in steel and similar workpiece materials, covering material application codes P, M, K, N, and S. The 4.125-inch overall length fits standard jobber-length drill chucks without requiring an extension. The 2.875-inch flute length accommodates the maximum drilling depth in a single pass without repositioning. It is appropriate for use in production drilling, repair work, and field maintenance scenarios where a heavy-duty grade cobalt bit is required. The bit meets NAS 907 and ANSI standards, making it suitable for aerospace and industrial maintenance applications.

Key Features

• Letter G size, 0.2610 inches decimal equivalent, for precise hole sizing
• 135-degree standard point with web thinning reduces thrust and self-centers on entry
• Cobalt high-speed steel construction handles elevated cutting temperatures in steel and hard alloys
• Oxide and straw proprietary coating improves wear resistance and reduces built-up edge
• Right-hand regular spiral flute with tapered web configuration promotes controlled chip evacuation
• Meets NAS 907 and ANSI standards for heavy-duty drilling applications

Compatibility

Designed as a direct-fit jobber-length drill bit for use in standard straight-shank drill chucks. Compatible with workpiece material codes P, M, K, N, and S per the Series R10CO-R15CO-R18CO classification. No coolant-through capability; intended for dry or externally lubricated drilling setups.

Installation Notes

Install in a standard drill chuck rated for straight cylindrical shanks at 0.2610 inches. Secure the chuck fully before operation and verify runout with a dial indicator when drilling to close tolerances. Power down and lock out the machine before changing bits. Use appropriate cutting fluid for steel workpieces to extend bit life and maintain hole quality.