Precision Twist Drill 5996386 Letter S Jobber Drill Bit

Product Description

The PRECISION TWIST DRILL 5996386 is a Letter S jobber-length drill bit ground from high-speed steel (HSS) with a straw bronze coating for heat resistance and lubricity. It is sized at 0.3480 inches in diameter and features a 135-degree split-point geometry with web thinning for fast penetration and reduced walking on entry. The two-flute, regular spiral design evacuates chips efficiently in through-hole and blind-hole drilling applications. At 4.875 inches overall length with a 3.5-inch flute length, it fits standard drill chucks without an adapter. Licensed HVAC, plumbing, electrical, and mechanical trades reach for this type of bit when drilling through high-temp alloys, cast iron, and ferrous materials on the job.

This bit is designed for heavy-duty general-purpose drilling in high-temperature alloys and similar hard metals, making it a standard choice for industrial maintenance, mechanical contractors, and trade fabrication work. The straight cylindrical shank seats directly in keyed or keyless chucks on corded and cordless drills and drill presses. The HX10-HX15-HX18 series designation indicates it is engineered to a 10xD flute-to-diameter ratio, suited for moderate-depth holes up to 3.5 inches. It carries an ANSI specification designation and is rated for right-hand cutting only.

Key Features

• Letter S diameter: 0.3480 inches for precise letter-size hole tolerance
• 135-degree split point with web thinning reduces thrust and eliminates center-punch requirements on most materials
• HSS construction with straw bronze coating improves surface hardness and heat dissipation
• Regular spiral, two-flute design promotes clean chip ejection in deep drilling
• Straight cylindrical shank fits standard drill chucks without reduction sleeves
• Meets ANSI specification standards; rated for high-temp alloy workpieces

Compatibility

Designed for use in standard three-jaw drill chucks accepting 0.3480-inch straight-shank tooling; part of the PRECISION TWIST DRILL HX10-HX15-HX18 series for heavy-duty general-purpose drilling applications.

Installation Notes

Install and remove drill bits only with the drill or drill press fully powered down and, where applicable, unplugged or locked out per OSHA lockout-tagout procedures. Secure the shank fully in the chuck and confirm the chuck key is removed before operation. Use appropriate cutting fluid or coolant when drilling high-temp alloys to extend tool life; note that this bit is not coolant-through rated. Proper RPM selection based on material and diameter should follow published speeds-and-feeds charts for HSS tooling.