Precision Twist Drill 5996381 Letter R Jobber Drill Bit

Product Description

The PRECISION TWIST DRILL 5996381 is a letter R jobber-length drill bit designed for general-purpose drilling in ferrous metals and hard alloys. It measures 0.3390 inches in diameter and 4.75 inches overall, with a 135-degree split-point angle and web-thinned tip that reduces walking on entry and lowers thrust force. The bronze coating improves lubricity and extends service intervals in production environments. Two spiral flutes with a regular helix evacuate chips efficiently in straight-through drilling operations. This bit is intended for use by machinists, maintenance mechanics, and trade professionals working with drill presses, lathes, or hand-held power tools.

The 5996381 is rated for drilling steel, stainless steel, cast iron, superalloys, and titanium — material codes P, M, K, and S in ISO classification. The straight-cylindrical shank seats in standard drill chucks without adapters. With a maximum drilling depth of 3.4375 inches and a flute-to-diameter ratio of 10xD, this bit handles deep-hole passes in typical fabrication and maintenance workflows. It belongs to the HX10-HX15-HX18 series and conforms to ANSI standards.

Key Features

• Letter R diameter: 0.3390 inches — standard jobber sizing for fractional and letter-gauge work
• 135-degree split point with web thinning reduces entry thrust and eliminates center-punch requirement on most metals
• Bronze-coated high speed steel construction improves heat resistance and lubricity during extended runs
• Right-hand, regular-helix spiral flutes provide reliable chip evacuation in through-hole and blind-hole drilling
• Straight-cylindrical shank fits standard 3-jaw drill chucks without sleeves or adapters
• ANSI-compliant geometry — consistent dimensional tolerances across the HX10-HX15-HX18 series

Compatibility

Designed as a general-purpose jobber drill for use with standard drill presses, milling machines, lathes, and hand-held power tools equipped with a chuck sized to accept a 0.3390-inch straight-cylindrical shank. Rated for steel, stainless steel, cast iron, superalloys, and titanium workpiece materials.

Installation Notes

Secure the shank fully in the drill chuck and verify runout before drilling. Power down the machine and lock out energy sources before changing bits or adjusting workpiece fixturing. Apply cutting fluid when drilling stainless steel, superalloys, or titanium to manage heat and extend tool life. Inspect the cutting edges for chipping or wear before each use and replace the bit if the point geometry is compromised.