Precision Twist Drill 5999426 Letter T Hss Drill Bit

Product Description

The PRECISION TWIST DRILL 5999426 is a jobber-length drill bit sized to Letter T (0.3580 inches) and designed for general-purpose drilling in a wide range of ferrous and non-ferrous materials. Ground from high speed steel with a steam oxide coating, it features a 118-degree standard point angle and a web-thinned, tapered web configuration that reduces thrust and improves chip clearance at drill entry. The two-flute regular spiral design handles drilling depths up to 3.5 inches, making it a practical choice for production and maintenance drilling on the shop floor or in the field. This bit is part of the Series R10-R15-R18 family and conforms to ANSI standards.

This drill bit is suited for drilling into steel, stainless steel, cast iron, non-ferrous metals, superalloys, and titanium. It is a right-hand cut tool with a straight-cylindrical shank, compatible with standard drill chucks in hand drills, drill presses, and milling machines. The 4.875-inch overall length fits within standard chuck clearances for both benchtop and portable setups, making it appropriate for HVAC, plumbing, electrical, and general mechanical trade work where Letter T sizing is required.

Key Features

• Letter T size: 0.3580 inches diameter, straight-cylindrical shank of equal diameter for positive chuck grip
• 118-degree standard point angle with web-thinned, tapered web for reduced entry thrust
• High speed steel construction with steam oxide coating for lubricity and light corrosion resistance during use
• Two-flute regular spiral design with a 10xD flute-to-diameter ratio supports chip evacuation in deeper holes
• Right-hand cut, compatible with standard drill chucks — no special tooling required
• ANSI-conforming dimensions for predictable sizing and interchangeability

Compatibility

Designed as a general-purpose jobber-length drill bit for use with standard three-jaw drill chucks accepting a 0.3580-inch straight-cylindrical shank. Suitable across Series R10-R15-R18 application contexts as specified by the manufacturer.

Installation Notes

Install and remove drill bits only with the drill or drill press powered off and the chuck key removed before startup. Secure the shank fully within the chuck jaws and tighten evenly to prevent runout. Use appropriate cutting fluid or coolant when drilling stainless steel, superalloys, or titanium to manage heat buildup, even though this bit does not support through-coolant. Inspect the cutting edges before use and replace the bit if chipping or excessive wear is present, as a dull bit increases thrust force and can damage the workpiece or shank.