Precision Twist Drill 5997221 Taper Length Drill Bit

Product Description

The PRECISION TWIST DRILL 5997221 is a taper length drill bit from the QC91P series, ground from high speed steel (HSS) with a bright uncoated finish. It features a 17/64 inch (0.2656 inch) diameter, a 135-degree split point for self-centering starts, and a parabolic flute geometry designed to evacuate chips efficiently during deep-hole drilling. The straight cylindrical shank fits standard drill chucks without adapters. This is a heavy-duty general-purpose bit intended for machinists, maintenance technicians, pipefitters, and fabricators who drill frequently in ferrous and non-ferrous materials.

The 5997221 is suited for drilling in a wide range of materials including alloy steel, carbon steel, stainless steel, hardened steel, tempered steel, cast iron, malleable iron, aluminum, aluminum alloy, brass, bronze, copper, magnesium, magnesium alloy, nickel, titanium, titanium alloy, and graphite. The taper length body provides extra reach compared to a jobber-length bit, making it practical for through-hole drilling in thicker stock or applications where a standard-length bit cannot reach the full depth. It is commonly used in machine shop, field maintenance, and fabrication environments.

Key Features

• 135-degree split point for self-centering entry without a pilot hole or center punch
• Parabolic flute profile promotes faster chip evacuation and reduces heat buildup in deep cuts
• Web-thinned, tapered web configuration reduces thrust force required during drilling
• Bright uncoated HSS construction suitable for a broad range of metals and alloys
• Taper length body at 6.25 inches OAL and 3.875 inch flute length provides extended reach beyond jobber-length bits
• Straight cylindrical shank with 0.2656 inch shank diameter fits standard three-jaw drill chucks
• Meets ANSI standards; rated heavy-duty for demanding general-purpose applications

Compatibility

Designed as an OEM-style replacement or direct-use taper length drill bit compatible with any standard drill chuck accepting a straight cylindrical shank at 0.2656 inch diameter, on benchtop drill presses, floor-standing drill presses, and portable electric drills used in general machining and fabrication work.

Installation Notes

Install and remove this bit with the drill unplugged or the machine locked out and tagged out per OSHA lockout/tagout procedures before chuck adjustment. Secure the shank fully in the chuck and verify concentricity before beginning a cut. Use appropriate cutting fluid or coolant when drilling stainless steel, titanium, or hardened steel to extend bit life. Wear eye protection and secure the workpiece in a vise or fixture — never hold the workpiece by hand during drilling.