Hertel 79892691 Solid Carbide Jobber Drill Bit Letter R

Product Description

The HERTEL 79892691 is a solid carbide jobber-length drill bit sized to Letter R (0.3390 inches) with a 118-degree standard point angle. Manufactured from C2-grade solid carbide with a bright finish, it delivers the hardness and wear resistance required for production drilling in ferrous and non-ferrous materials. The web-thinned, tapered web geometry reduces thrust and improves chip evacuation at drill entry. With a 4-inch overall length and a 2.5-inch spiral flute length, this is a standard jobber format suited to a wide range of drilling applications on the bench or under power feed.

This drill bit is intended for use in metalworking and industrial machining environments where dimensional accuracy and tool longevity are required. The straight-cylindrical shank seats directly in standard drill chucks and collet holders without adapter sleeves. Right-hand cut with regular spiral fluting, it is appropriate for use in drill presses, CNC machining centers, and hand-held power drills where the operator needs a reliable, close-tolerance hole in a single pass. Machinists, tool-and-die technicians, and maintenance mechanics are the typical end users.

Key Features

• Solid carbide construction (C2 grade) for hardness and extended tool life in demanding materials
• Letter R size — 0.3390 inches decimal equivalent — with a tight diameter tolerance of -0.0005 to 0.0000 inches
• 118-degree standard point angle with web-thinned, tapered web for reduced entry thrust
• Bright finish — no coating buildup that could alter finished hole diameter
• 2-flute, regular spiral configuration promotes chip clearance in through-hole drilling
• Straight-cylindrical shank compatible with standard drill chucks and collet systems

Compatibility

Designed as a jobber-length replacement or production drill bit for any application requiring a Letter R (0.3390-inch) hole diameter; fits standard drill chucks and collets accepting a 0.3390-inch straight shank.

Installation Notes

A licensed machinist or qualified maintenance technician should verify spindle speed and feed rate against the workpiece material before use. Secure the shank fully in the chuck or collet and confirm concentricity before initiating the cut. Carbide tooling is brittle — avoid side loading, interrupted cuts without proper support, or dropping the bit on hard surfaces. Always wear appropriate eye protection and ensure the workpiece is clamped securely before drilling.