Precision Twist Drill 5998920 Taper Length Drill Bit

Product Description

The PRECISION TWIST DRILL 5998920 is a taper length high speed steel drill bit designed for precision hole-making in non-ferrous and soft metals. Ground to a 118-degree standard point angle with a web-thinned, tapered web configuration, it reduces thrust and improves chip clearance on entry. The bright/uncoated finish suits general purpose shop use. At 0.4375 inches (7/16 inch) diameter with a 4.625-inch flute length and 7.25-inch overall length, this bit fits standard drill press and handheld power tool chucks. The fast spiral flute and 6xD flute-to-diameter ratio promote efficient chip evacuation. Right-hand cut only. Meets ANSI standards. Installed by machinists, maintenance techs, and skilled tradespeople across fabrication and mechanical service applications.

This bit is suited for drilling aluminum, aluminum alloy, copper, magnesium, and magnesium alloy workpieces. The taper length profile provides additional reach compared to a jobber-length bit, making it appropriate for deeper hole applications or where standard-length bits fall short. The cylindrical, non-threaded shank seats directly in standard drill chucks without an adapter. It is a general purpose grade bit appropriate for production and repair environments working primarily with non-ferrous materials.

Key Features

• 118-degree standard point angle with web-thinned tapered web for reduced entry thrust
• Fast spiral flute with 6xD flute-to-diameter ratio for efficient chip removal
• Bright/uncoated finish — no coating to add or maintain
• Taper length body at 7.25 inches overall provides extended reach versus jobber length
• Right-hand cut, cylindrical shank fits standard drill chucks directly
• Meets ANSI standards; Series R51FS general purpose grade

Compatibility

Designed as a general purpose taper length drill bit compatible with standard drill press, magnetic drill, and handheld power tool chucks accepting a 0.4375-inch cylindrical shank. Rated for use in aluminum, aluminum alloy, copper, magnesium, and magnesium alloy materials per Series R51FS specifications.

Installation Notes

Install and remove drill bits only with the drill fully powered down and the chuck key removed from the machine. Secure the workpiece with appropriate clamping before drilling to prevent movement. Use cutting fluid or lubricant appropriate for the workpiece material to extend tool life, particularly when drilling copper or aluminum. Inspect the cutting edges and point geometry before each use and replace the bit if chipping or excessive wear is present.