Hertel 84578715 Jobber Drill Bit Letter T Hss Tin

Product Description

The HERTEL 84578715 is a jobber-length twist drill bit sized to letter T (0.3580 inches decimal), designed for general-purpose drilling in metal, wood, and plastic. Built from high speed steel (HSS) with a titanium nitride (TiN) coating, it delivers extended tool life compared to uncoated HSS by reducing heat buildup and surface friction at the cutting edge. The 118-degree standard point angle suits a wide range of common materials without requiring specialized geometry. With a 4.875-inch overall length and a 3.5-inch flute length, this bit fits standard drill chucks and drill presses used in production and maintenance environments. Machinists, millwrights, and maintenance technicians are the primary users.

This bit is suited to light-to-medium production drilling, MRO work, and general shop operations where a letter-T diameter hole is required. The straight cylindrical shank accepts standard three-jaw chucks on benchtop drill presses, floor-standing drill presses, and hand-held electric drills. The regular spiral flute geometry and tapered web configuration with web thinning promote chip evacuation and reduce thrust load during entry, making it practical for through-hole work in steel, aluminum, and similar materials.

Key Features

• Letter T size, 0.3580 inches decimal diameter, within the 0.3500 to 0.4000 inch range
• High speed steel construction with TiN coating for extended cutting life
• 118-degree standard point angle for general-purpose use across common materials
• Web-thinned tapered web reduces entry thrust and improves chip flow
• 2-flute regular spiral geometry with right-hand cut
• Straight cylindrical shank, 0.3580 inches, fits standard drill chucks without adapters

Compatibility

Designed as a general-purpose jobber-length drill bit for use in standard three-jaw drill chucks accepting straight cylindrical shanks up to 0.3580 inches in diameter.

Installation Notes

Install in a properly sized three-jaw chuck and tighten securely with a chuck key before operating. Set drill speed appropriate to the workpiece material and bit diameter — consult a speeds-and-feeds reference chart for HSS TiN-coated tooling. Secure the workpiece firmly before drilling to prevent rotation. Do not apply excessive downward pressure; let the cutting edge do the work to avoid premature coating wear or tip breakage.