Precision Twist Drill 5998983 Drill Bit Letter Y Hss

Product Description

The PRECISION TWIST DRILL 5998983 is a jobber length drill bit sized to Letter Y (0.4040 inches) for general-purpose drilling in metal and hard materials. Built from high speed steel with a steam oxide coating, it resists wear and handles heat generated during drilling in demanding materials. The 135-degree split point reduces walking on entry and requires less thrust than a 118-degree point. At 5.25 inches overall length with a 3.875-inch spiral flute, it covers the standard jobber reach needed for most production and maintenance drilling applications. Installation is performed by licensed machinists, maintenance technicians, and trades professionals using a standard drill press, CNC machine, or portable drill.

This drill bit is designed for right-hand cutting in steel, stainless steel, cast iron, non-ferrous metals, superalloys, and titanium. The tapered web and web-thinned geometry reduce axial load in harder workpiece materials. With a regular spiral and two-flute configuration, it evacuates chips efficiently during through-hole and blind-hole operations. The straight-cylindrical shank at 0.4040 inches diameter fits standard Jacobs-style chucks and collet holders common in shop and field use. It meets ANSI standards and carries an NAS 907 specification designation, making it suitable for aerospace and heavy industrial environments where dimensional compliance is required.

Key Features

• Letter Y size — 0.4040 inches decimal equivalent
• 135-degree standard point with web-thinned, tapered web for reduced entry thrust
• High speed steel construction with steam oxide coating for wear and heat resistance
• Two-flute regular spiral design for efficient chip evacuation
• Straight-cylindrical shank fits standard chucks and collet holders
• Meets ANSI standards and NAS 907 specification
• Rated for steel, stainless steel, cast iron, non-ferrous metals, superalloys, and titanium

Compatibility

Compatible workpiece materials include steel, stainless steel, cast iron, non-ferrous metal, superalloys, and titanium as specified by material codes P, M, K, N, and S. Fits standard drill chucks and collet systems accepting a 0.4040-inch straight-cylindrical shank. Part of the R10B, R15B, and R18B series.

Installation Notes

This bit is installed by machinists, maintenance technicians, and industrial tradespeople using a drill press, CNC spindle, or handheld drill with an appropriately sized chuck or collet. Secure the shank fully in the chuck before operation and verify runout is within acceptable limits for the application. Use cutting fluid appropriate to the workpiece material to extend tool life and improve finish quality. Do not exceed the maximum drilling depth of 3.875 inches in a single pass without clearing chips.