Precision Twist Drill 5998734 Letter a Hss Jobber Drill Bit

Product Description

The PRECISION TWIST DRILL 5998734 is a jobber-length twist drill bit sized at Letter A (15/64 inch, 0.2340 inch decimal), designed for general-purpose drilling in a wide range of materials including steel, stainless steel, cast iron, non-ferrous metals, superalloys, and titanium. The 135-degree split-point geometry reduces walking at startup and cuts through hard materials with less feed pressure than a standard 118-degree point. A steam oxide coating provides light corrosion resistance and improves surface lubricity. The bit is ground from high speed steel (HSS) and is built to heavy-duty grade standards, making it a reliable choice for machinists, maintenance technicians, fabricators, and pipefitters doing production or field drilling work.

This drill bit is suited for drilling steel and hard metals in both shop and field environments. The straight-cylindrical shank fits standard three-jaw chucks on drill presses, handheld drills, and CNC drill stations. The regular spiral flute and tapered web configuration promote efficient chip evacuation, which matters when drilling deeper holes in interrupted cuts or tough alloys. At 3.875 inches overall length with a 2.625-inch flute length, it handles depth-to-diameter ratios up to approximately 11xD without extension. Two flutes and a web-thinned point complete the geometry for reduced thrust and cleaner entry.

Key Features

• Letter A size: 0.2340 inch diameter, equivalent to 15/64 inch
• 135-degree split point reduces bit walking and lowers required feed pressure on hard materials
• Steam oxide coating improves lubricity and provides light rust resistance
• High speed steel construction rated for steel, stainless steel, cast iron, non-ferrous metals, superalloys, and titanium
• Web-thinned tapered web reduces thrust and extends tool life in heavy-duty applications
• Straight-cylindrical shank fits standard drill chucks without adapters
• Meets ANSI and NAS 907 standards; Series R10B-R15B-R18B

Compatibility

Designed as a direct-fit replacement or standard jobber-length drill bit for any application requiring a Letter A (0.2340 inch) straight-shank twist drill. Fits standard three-jaw drill chucks and is compatible with drill presses, hand drills, and CNC drilling equipment accepting straight-cylindrical shanks of 15/64 inch diameter.

Installation Notes

Installation and use should be performed by a qualified machinist or technician familiar with rotating cutting tools. Secure the shank fully in the chuck and verify concentricity before drilling. Always wear appropriate eye protection and secure the workpiece before starting the spindle. Do not exceed the recommended cutting speed for the workpiece material, and use cutting fluid when drilling stainless steel, superalloys, or titanium to extend tool life and maintain hole quality.