Precision Twist Drill 5998917 Taper Length Drill Bit

Product Description

The PRECISION TWIST DRILL 5998917 is a taper length drill bit in the R51FS series, designed for accurate hole drilling in soft to medium metals and non-ferrous materials. Built from high-speed steel (HSS) with a bright uncoated finish, this bit features a 118-degree standard point angle and a fast spiral flute configuration. The 5/64 inch (0.0781 inch decimal) diameter suits applications where close-tolerance, smaller-diameter holes are required. The web-thinned, tapered web construction reduces thrust during entry, making it a reliable choice for production and maintenance drilling tasks performed by machinists, millwrights, and general metalworking tradespeople.

This taper length bit is suited for drilling aluminum, aluminum alloy, copper, magnesium, and magnesium alloy workpieces. Its taper length body — longer than a jobber bit but shorter than an extra-long series — provides added reach and rigidity for applications where standard jobber length falls short. The cylindrical shank fits conventional three-jaw drill chucks on bench drills, drill presses, and hand drills. Right-hand cut spiral flutes clear chips efficiently during through-hole drilling operations. The R51FS series is built to ANSI standards, making it a general-purpose workhorse for shop and field use alike.

Key Features

• High-speed steel construction for durability across a range of non-ferrous and soft metal materials
• 118-degree standard point angle for reliable self-centering on flat and curved surfaces
• Web-thinned, tapered web reduces cutting thrust and improves penetration efficiency
• Fast spiral flute design promotes aggressive chip evacuation during drilling
• Bright uncoated finish — no coating buildup to affect dimensional accuracy on small-diameter work
• ANSI-standard geometry ensures compatibility with standard tooling and fixture setups

Compatibility

Designed for use in standard three-jaw drill chucks accepting a cylindrical shank diameter of 0.0781 inches. Rated for drilling aluminum, aluminum alloy, copper, magnesium, and magnesium alloy per supplier material application data. Part of the PRECISION TWIST DRILL R51FS series.

Installation Notes

Machinists and maintenance technicians should secure the workpiece firmly before drilling to prevent walking on entry. Power down and de-energize all equipment before mounting or changing bits. Use appropriate cutting fluid or lubricant when drilling copper or aluminum alloys to extend bit life and improve hole finish. Inspect the cutting edges before use and discard bits with visible chipping or excessive wear to maintain hole-diameter accuracy.