Hertel 79892139 Solid Carbide Jobber Drill Bit No. 28

Product Description

The HERTEL 79892139 is a solid carbide jobber-length drill bit sized to wire gauge No. 28 (0.1405 inches decimal equivalent). Built from C2-grade solid carbide with a bright finish, it delivers consistent hole geometry in hard and abrasive materials where high-speed steel tooling wears prematurely. The 118-degree standard point angle suits general-purpose drilling across a broad range of workpiece materials. A web-thinned, tapered web design reduces entry thrust and improves chip evacuation. At 2.5 inches overall length with a 1.375-inch spiral flute, this bit fits standard drill chucks and CNC spindles with a straight cylindrical shank. Diameter tolerance is held at -0.0005 to 0.0000 inches for precise, repeatable hole sizing.

This bit is suited for production and maintenance drilling in metalworking, aerospace, automotive, and light manufacturing environments. The regular-spiral, two-flute geometry handles drilling in steel, cast iron, non-ferrous metals, and certain plastics. It is installed and run by machinists, tool-and-die technicians, and maintenance mechanics using benchtop drill presses, hand drills, or CNC machining centers. It is sold and packaged as a single unit.

Key Features

• C2-grade solid carbide construction resists wear in hard and abrasive workpiece materials
• Bright (uncoated) finish maintains sharp cutting edges and suits a wide material range
• 118-degree standard point angle for general-purpose drilling applications
• Web-thinned tapered web reduces thrust load and improves chip flow
• Straight cylindrical shank fits standard drill chucks and collets without modification
• Diameter tolerance of -0.0005 to 0.0000 inches ensures consistent hole size

Compatibility

Designed as a general-purpose jobber-length drill bit compatible with any standard drill chuck or collet accepting a 0.1405-inch straight cylindrical shank, including benchtop drill presses, hand drills, and CNC machining center toolholders.

Installation Notes

Secure the shank fully in the chuck or collet before operation and verify runout is within acceptable limits for the application. Solid carbide is brittle compared to high-speed steel — avoid side loading, interrupted cuts without appropriate feed reduction, and dropping or striking the flutes. Apply cutting fluid or coolant appropriate to the workpiece material to extend tool life, noting that this bit does not support through-coolant delivery. Follow applicable shop safety standards and machine guarding requirements during setup and operation.