Precision Twist Drill 5999136 Jobber Drill Bit Letter U Hss

Product Description

The PRECISION TWIST DRILL 5999136 is a jobber-length drill bit sized to Letter U (0.3680 inches decimal equivalent), designed for general-purpose drilling in demanding trade and industrial applications. Built from high speed steel with a steam oxide coating, this bit runs a 135-degree split point that reduces walking on entry and lowers thrust requirements compared to a conventional 118-degree point. The straight-cylindrical shank seats securely in standard three-jaw chucks, and the two-flute regular spiral geometry evacuates chips efficiently through a 3.625-inch flute length. Overall length is 5 inches. Web thinning on the tapered web further reduces cutting resistance. This is a heavy-duty grade bit suited for production and maintenance drilling alike.

This bit is rated for drilling steel, stainless steel, cast iron, non-ferrous metals, superalloys, and titanium, covering the ISO material groups P, M, K, N, and S. That range makes it a practical single-bit choice for HVAC techs drilling sheet metal and structural steel, plumbers drilling cast iron and copper-bearing fixtures, electricians drilling panel knockouts and unistrut, and general maintenance trades working across mixed-material environments. Maximum drilling depth matches the flute length at 3.625 inches. Series designation covers R10B, R15B, and R18B. Conforms to ANSI and NAS 907 standards.

Key Features

• Letter U size: 0.3680 inches decimal equivalent for precise hole sizing
• 135-degree split point reduces walking and lowers feed pressure at entry
• High speed steel construction with steam oxide coating for lubricity and corrosion resistance
• Web-thinned tapered web reduces cutting torque and extends bit life
• Two-flute regular spiral with 3.625-inch flute length for effective chip evacuation
• Straight-cylindrical shank fits standard drill chucks without adapters
• Conforms to ANSI and NAS 907 specifications for dimensional accuracy

Compatibility

Designed as a general-purpose jobber-length drill bit compatible with any standard three-jaw drill chuck accepting a 0.3680-inch straight-cylindrical shank, including benchtop drill presses, hand drills, and right-angle drill attachments used across HVAC, plumbing, electrical, and mechanical trades.

Installation Notes

A licensed or experienced tradesperson should secure the bit fully into the chuck and verify runout before drilling. Always wear eye protection and appropriate gloves when operating drill equipment. Use cutting fluid or coolant when drilling stainless steel, superalloys, or titanium to manage heat buildup and extend bit life. Power down the drill and allow the bit to fully stop before changing bits or clearing chip buildup from the flutes.